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Introduction: Intraoperative radiotherapy (IORT) with electrons has revealed to have higher rates of ipsilateral breast tumor recurrence (IBTR) than external beam radiotherapy in updated large-scale, randomized controlled trials in 2021. This study details the oncological outcomes of IORT with electron beams using our strict IORT policies. We have found new and important observations regarding the location of recurrence. Methods and materials: This is a single institution registry of early-stage breast cancer patients who underwent lumpectomy and electron beam IORT with appropriate cone size. All patients met our pre-excision requirements. The primary endpoint was 5-year IBTR rate, with secondary endpoints being 5-year locoregional failure rate, 5-year distant metastasis rate, 5-year overall survival and, importantly, the failure patterns. Results: Between January 2011 and December 2022, 124 patients were recruited. The median follow-up was 6.7 years. The 5-year IBTR rate was 1.87% (95% CI 0.47–7.29%), which is much lower than the ELIOT trial and comparable with other accelerated partial breast irradiation (APBI) techniques. The 5-year locoregional failure rate was 3.68% (95% CI 1.40–9.52%), and the 5-year distant metastasis rate was 0.88% (95% CI 0.13–6.12%), while the 5-year overall survival rate was 97.52% (95% CI 92.44–99.19%). Six patients experienced IBTR. All recurrences were in surgical area, occurring superficial to the tumor bed and within 1 cm of the skin dermis. This failure pattern is very unique and might be explained by our hypothesis of the non-irradiated area beneath the skin. Conclusions: IORT with electron beams with strict patient selection criteria and strict large cone size is still an acceptable treatment for select patients with early-stage breast cancer. However, our new findings support extreme caution in the non-irradiated area beneath the skin around the tumor cavity. Given the constraints of our sample size, these findings should be interpreted cautiously and warrant further investigation in larger, more comprehensive studies. [ABSTRACT FROM AUTHOR]

Background: Accelerated partial breast irradiation (APBI) is an alternative breast-conserving therapy approach where radiation is delivered in less time compared to whole breast irradiation (WBI), resulting in improved patient convenience, less toxicity, and cost savings. This prospective randomized study compares the external beam APBI with commonly used moderate hypofractionated WBI in terms of feasibility, safety, tolerance, and cosmetic effects. Methods: Early breast cancer patients after partial mastectomy were equally randomized into two arms– external APBI and moderate hypofractionated WBI. External beam technique using available technical innovations commonly used in targeted hypofractionated radiotherapy to minimize irradiated volumes was used (cone beam computed tomography navigation to clips in the tumor bed, deep inspiration breath hold technique, volumetric modulated arc therapy dose application, using flattening filter free beams and the six degrees of freedom robotic treatment couch). Cosmetics results and toxicity were evaluated using questionnaires, CTCAE criteria, and photo documentation. Results: The analysis of 84 patients with a median age of 64 years showed significantly fewer acute adverse events in the APBI arm regarding skin reactions, local and general symptoms during a median follow-up of 37 months (range 21–45 months). A significant difference in favor of the APBI arm in grade ≥ 2 late skin toxicity was observed (p = 0.026). Late toxicity in the breast area (deformation, edema, fibrosis, and pain), affecting the quality of life and cosmetic effect, occurred in 61% and 17% of patients in WBI and APBI arms, respectively. The cosmetic effect was more favorable in the APBI arm, especially 6 to 12 months after the radiotherapy. Conclusion: External APBI demonstrated better feasibility and less toxicity than the standard regimen in the adjuvant setting for treating early breast cancer patients. The presented study confirmed the level of evidence for establishing the external APBI in daily clinical practice. Trial registration: NCT06007118. [ABSTRACT FROM AUTHOR]

Purpose: We investigated the long-term oncological outcome of high-dose-rate (HDR) multicatheter interstitial brachytherapy (MIB) for adjuvant accelerated partial breast irradiation (APBI) after breast conserving surgery in Japanese patients. Material and methods: Between June 2002 and October 2011, 86 breast cancer patients were treated at National Hospital Organization Osaka National Hospital (trial number of the local institutional review board, 0329). Median age was 48 years (range, 26-73 years). Eighty patients had invasive and 6 patients non-invasive ductal carcinoma. Tumor stage distribution was pT0 in 2, pTis in 6, pT1 in 55, pT2 in 22, and pT3 in one patient, respectively. Twenty-seven patients had close/positive resection margins. Total physical HDR dose was 36-42 Gy in 6-7 fractions. Results: At a median follow-up of 119 months (range, 13-189 months), the 10-year local control (LC) and overall survival rate was 93% and 88%, respectively. Concerning the 2009 Groupe Européen de Curiethérapie-European Society for Therapeutic Radiology and Oncology risk stratification scheme, the 10-year LC rate was 100%, 100%, and 91% for patients considered as low-risk, intermediate-risk, and high-risk, respectively. According to the 2018 American Brachytherapy Society risk stratification scheme, the 10-year LC rate was 100% and 90% for patients 'acceptable' and 'unacceptable' for APBI, respectively. Wound complications were observed in 7 patients (8%). Risk factors for wound complications were the omission of prophylactic antibiotics during MIB, open cavity implantation, and V100 ≥ 190 cc. No grade ≥ 3 late complications (CTCVE version 4.0) were observed. Conclusions: Adjuvant APBI using MIB is associated with favorable long-term oncological outcomes in Japanese patients for low-risk, intermediate-risk, and acceptable groups of patients. [ABSTRACT FROM AUTHOR]

In selected low-risk breast cancer patients, accelerated partial breast irradiation (APBI) may represent an alternative option to the whole breast irradiation to reduce the volume of irradiated breast and total treatment duration. In the last few years, preliminary data from clinical trials showed that stereotactic partial breast radiotherapy may have the advantage to be less invasive compared to other APBI techniques, with preliminary good results in terms of local toxicity and cosmesis: the use of magnetic resonance, fiducial markers in the tumor bed, and new breast devices support both a precise definition of the target and radiation planning. [ABSTRACT FROM AUTHOR]

Simple Summary: Breast cancer is the most common cancer in the female population. Adjuvant radiotherapy has become increasingly important as conservative treatment. Muticatheter interstitial brachytherapy is a type of radiation technique wherein the radioactive sources are directly implanted into or close to the target tissue and may be considered an extremely precise, versatile, and variable radiation technique. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy, with particular focus on the implant description, limits, and advantages of the technique. Breast cancer represents the second leading cause of cancer-related death in the female population, despite continuing advances in treatment options that have significantly accelerated in recent years. Conservative treatments have radically changed the concept of healing, also focusing on the psychological aspect of oncological treatments. In this scenario, radiotherapy plays a key role. Brachytherapy is an extremely versatile radiation technique that can be used in various settings for breast cancer treatment. Although it is invasive, technically complex, and requires a long learning curve, the dosimetric advantages and sparing of organs at risk are unequivocal. Literature data support muticatheter interstitial brachytherapy as the only method with strong scientific evidence to perform partial breast irradiation and reirradiation after previous conservative surgery and external beam radiotherapy, with longer follow-up than new, emerging radiation techniques, whose effectiveness is proven by over 20 years of experience. The aim of our work is to provide a comprehensive view of the use of interstitial brachytherapy to perform breast lumpectomy boost, breast-conserving accelerated partial breast irradiation, and salvage reirradiation for ipsilateral breast recurrence, with particular focus on the implant description, limits, and advantages of the technique. [ABSTRACT FROM AUTHOR]

• APBI use is stable since 2008, but with a drop in brachytherapy and a rise in IORT. • There is a steady rise in patients considered "suitable" by ASTRO APBI guidelines. • Trends in APBI modality utilization appears to be influenced by available literature. To examine recent modality utilization trends in accelerated partial breast irradiation (APBI) in the National Cancer Database (NCDB) based on the American Society for Radiation Oncology (ASTRO) guidelines. A total of 58,194 patients treated with APBI were identified. Patients were segregated by APBI modality (brachytherapy, external beam radiotherapy [EBRT], and intraoperative radiotherapy ([IORT]). These patients were then further classified by suitability to receive APBI based on ASTRO guidelines. Temporal trends in utilization were evaluated using linear regression. Logistic regression was applied to study factors contributing to APBI modality choice and treatment within the ASTRO suitability groups. Patients treated with brachytherapy, EBRT, and IORT comprised 70.5%, 17.5%, and 12.0% of patients treated with APBI. From 2008 to 2017, total APBI cases remained relatively stable (−54.1 cases/year, p = 0.161) while brachytherapy cases decreased by 258.7 cases/year (p < 0.001). EBRT and IORT increased by 51.5 cases/year (p = 0.019) and 153.1 cases/year (p < 0.001), respectively. 40.0% of patients treated with APBI were classified as "suitable", which increased from 2010 to 2017 from 35.3% to 45.3% (slope = 1.51%/year, r 2 = 0.61, p = 0.022). In comparison, 36.0% (36.1% in 2010 to 33.1% in 2017) of patients were classified as "cautionary" (slope = −0.33%/year, r 2 = 0.63, p = 0.019) and 23.9% (28.6% in 2010 to 21.6% in 2017) of patients were classified as "unsuitable" (slope = −1.18%/year, r 2 = 0.67, p = 0.012). While overall APBI utilization has remained stable since 2008, this has been accompanied by a decline in brachytherapy and a rise in IORT. The causes of these trends should be the topic of future research. [ABSTRACT FROM AUTHOR]

• Prospective dosimetric outcomes for stereotactic MR-guided stereotactic APBI. • In both the 1 and 3 fraction trials, 88.53% of the dosimetric objectives were met. • SBRT-style dosimetry for APBI is feasible using MR-guidance. • Guide for other institutions for clinical implementation of MRg-SAPBI. Accelerated partial breast irradiation (APBI) seeks to reduce irradiated volumes and radiation exposure for patients while maintaining acceptable clinical outcomes. Magnetic resonance image-guided radiotherapy (MRgRT) provides excellent soft-tissue contrast for treatment localization, which can reduce setup uncertainty, thus reducing margins in the external beam setting. Additionally, stereotactic body radiotherapy (SBRT)-style regimens with high gradients can also be executed. This MR-guided stereotactic APBI (MRgS-APBI) approach can be utilized for a lower number of fractions and spare a greater volume of healthy tissues compared to conventional 3D external beam APBI. Our MRgS-APBI program was developed for two prospective non-randomized phase I/II clinical trials (20Gyx1 and 8.5Gyx3). Both breast SBRT treatment planning and MRgRT delivery techniques were described in this study. Simulation included both CT and MRI with specialized immobilization to accommodate MR-guided setup and cine-MRI treatment gating. Dosimetry data from 48 single-fraction and 19 three-fraction patients were collected and evaluated. This included planning objectives and SBRT-specific indices. During treatment, setup errors were calculated to evaluate setup reproducibility and duty cycle was calculated using cine-MRI data during gated delivery. In both the single- and three- fraction trials combined, 88.5% of the possible dosimetric objectives across all patients were met during planning. The majority of the planning objectives were easily achievable indicating the potential for stricter objectives for subsequent S-APBI treatments. The average magnitude of setup uncertainties was 1.0 cm ± 0.6 cm across all treatments. In the three-fraction trial, the average beam-on duty-cycle for the MRI-gated delivery was 83.0 ± 13.0%. There were no technical MRgS-APBI related issues that resulted in discontinuation of treatment across all patients. SBRT-style dosimetry and delivery for APBI is feasible using MR-guidance. The program development and dosimetric outcomes reported here can serve as a guide for other institutions considering the clinical implementation of MR-guided stereotactic APBI. [ABSTRACT FROM AUTHOR]

Background: angiosarcoma may rarely complicate radiotherapy of breast cancer. This so-called radiation-induced angiosarcoma (RIAS) occurs in less than 0.3% of patients that underwent breast conservation surgeries, usually years after completion of radiotherapy. Case presentation: we introduce two cases of invasive ductal carcinoma who underwent lumpectomy and accelerated partial breast irradiation (APBI) as an alternative protocol to whole breast irradiation (WBI). They received adjuvant partial breast radiotherapy on tumor cavity for a total dose of 38.5 Gy in 10 fractions in 5 days using 3D-external-beam RT. In both cases, RIAS occurred eight years after radiotherapy, in the sub-cicatricial area in one patient and outside the irradiated area in the other one. They both underwent radical surgery and chemotherapy was performed in one patient. Discussion: the underlying mechanism for development of RIAS is not well known, but its incidence seems to be increasing. RIAS after partial breast irradiation is very rare and has been reported in two cases so far. As it may be suggested in case 2, it is still a matter of debate if the risk of radiation-induced sarcoma is radiation-dose dependent. Although mastectomy is considered as a standard treatment, choice of treatment should be made according to the patient's specifications. Conclusion: there are very few studies in the literature that report RIAS after APBI. Present study is the only one reporting two cases after the external 3D technique APBI. Prognosis of RIAS remains poor. Only a careful evaluation in a multidisciplinary context can offer to the patients the best result in terms of local control and survival. [ABSTRACT FROM AUTHOR]

Purpose: The aim of this study was to compare patient-reported quality of life (QOL) scores after accelerated partial breast irradiation (APBI) using interstitial brachytherapy vs. external beam whole breast radiotherapy (WBRT) for breast cancer. Material and methods: Women with breast cancer treated with WBRT or APBI after breast conservation surgery were enrolled in this prospective study. Single cross-sectional QOL assessment was performed using EORTC QLQ-C30 and BR-23 questionnaires. Patients treated with APBI were propensity-score matched to similar cohort of patients treated with WBRT. QOL scores were analyzed for the entire unmatched cohort and compared between the two matched cohorts using Student's two-tailed t-test. P-value of < 0.05 was considered statistically significant, and a 10-point difference between mean scores was considered clinically meaningful. Results: A total of 64 APBI patients were matched with 99 WBRT patients out of the entire study cohort of 320 cases. QOL scores for functional scales of QLQ-C30 were similar between the two groups for both matched and unmatched cohorts, while symptom scores of QLQ-C30 did not show any clinically significant difference. Functional scales of BR-23 did not show any clinical or statistically significant difference. Among symptom scales of BR-23, scores were similar for APBI and WBRT groups except for a worse score of "upset by hair loss" sub-scale in the brachytherapy group of the matched cohort (51.9 vs. 22.7, p = 0.006). Conclusions: Patients undergoing APBI reported similar QOL compared to WBRT when matched for various factors. [ABSTRACT FROM AUTHOR]

The noninvasive image-guided breast brachytherapy (NIBB) technique is a novel noninvasive yet targeted method for accelerated partial breast irradiation. We established a multi-institutional registry to evaluate the toxicity and efficacy of this technique across various practice settings. Institutions using the NIBB technique were invited to participate. Data for acute/late toxicity, cosmetic outcome, and tumor recurrence were collected. Toxicity and cosmetic outcome were graded based on the Common Terminology Criteria for Adverse Events version 3.0 and NRG/Radiation Therapy Oncology Group scale, respectively. Treatment variables were analyzed for association with outcomes. A total of 252 patients from eight institutions were analyzed. The median age was 69 years. The mean tumor size was 1.1 cm (0.1–4.0 cm). Treatment was delivered 10 fractions (34–36 Gy) in 75% and five fractions (28.5 Gy) in 22%. B.i.d. fractionation was used in 9%. Acute radiation dermatitis was Grade 0–1, 2, and 3 in 77%, 19%, and 4%, respectively. One hundred ninety-one patients with a median followup of 18 months (4–72 months) were evaluable for late outcomes. Late toxicity Grades 2 and 3 were observed in 8.8% and 1%, respectively. Cosmetic outcome was excellent, good, and fair/poor in 62%, 36%, and 2%, respectively. B.i.d. fractionation was associated with higher acute and late toxicity. Second-generation applicators were associated with lower late toxicity and better cosmetic outcome. Actuarial freedom from ipsilateral breast tumor recurrence and true recurrence were 98.3% and 98.3% at 2 years and 90.9% and 95.4% at 5 years, respectively. Accelerated partial breast irradiation using NIBB was well tolerated with a low rate of acute and late toxicity across various practice settings. Ipsilateral breast tumor recurrence and cosmetic outcomes were favorable. b.i.d. fractionation was associated with higher toxicity. Longer followup is needed to confirm late endpoints. [ABSTRACT FROM AUTHOR]

Mammographically based noninvasive image-guided breast brachytherapy (NIBB) partial breast irradiation (PBI) is ideally suited for preoperative treatment. We hypothesize that delivering NIBB PBI to the preoperative tumor volume compared with the postoperative lumpectomy bed would simplify target identification and allow for a reduction in irradiated volume along each orthogonal axis. Patients with invasive breast cancer treated with NIBB PBI at our institution were identified. Preoperative NIBB treatments were modeled along orthogonal craniocaudal and mediolateral axes with an applicator encompassing the gross lesion plus a 1 cm clinical target volume margin. Preoperative treatment volumes were calculated along each axis using the selected applicator surface area multiplied by the preoperative mammogram separation. The actual applicator size and breast separation from the first fraction of postoperative treatment was used to calculate the postoperative treatment volume. Paired -test was used to compare the preoperative and postoperative treatment separation, area, and volume for each patient. Forty-eight patients with Stage I–II breast cancer had imaging and treatment data available for review. Along the axis, the mean preoperative treatment volume was significantly less than the mean postoperative treatment volume (116 cm 3 vs. 204 cm 3, respectively; p < 0.0001). Similarly, along the mediolateral axis, the mean preoperative treatment volume was significantly less than the mean postoperative treatment volume (125 cm 3 vs. 216 cm 3, respectively; p < 0001). Based on our retrospective comparison, PBI delivered using NIBB to the preoperative tumor may reduce the volume of healthy breast tissue receiving radiation as compared with NIBB to the postoperative tumor bed. [ABSTRACT FROM AUTHOR]

This is a multicenter Phase I–II trial endorsed by the GEC-ESTRO Breast Working Group, to analyze if very accelerated partial breast irradiation (VAPBI) with multicatheter interstitial brachytherapy is feasible and safe compared with the standard APBI treatment in 4–5 days for early stage breast carcinomas. We have included 81 patients with pT1-2 pN0 invasive carcinomas after breast-conserving surgery. Between August 2017 and July 2019, 33 women received high-dose-rate brachytherapy, four fractions of 6.25 Gy in 2–3 days, and 48 patients received three fractions of 7.45 Gy in 2 days. Thirty-six patients were implanted perioperatively and 45 postoperatively. Mean age was 68 (51–90). Free surgical margins were of 2 mm or greater. Acute effects were 11% dermatitis, 18.5% hematoma, 3.7% infection, and 14.8% pain. At a median followup of 20 months (range 8–35), no relapse has occurred. Pigmentation changes in the entrance and exit of tubes were visible in 16%, but 1 year later, few cases remained. Patients developed G1-2 induration or fibrosis in 18.5% and 2.5%, respectively. No patient developed telangiectasia. The cosmetic outcome was good/excellent in 97.5% and fair in 2.5%. VAPBI with multicatheter interstitial brachytherapy using four fractions of 6.25 Gy or three fractions of 7.45 Gy in two or 3 days is feasible. No excess has been observed in acute effects. At a mean followup of 20 months, late side effects seem to be similar to standard fractionation. VAPBI in two to 3 days is beneficial for the patients and reduces the workload of the brachytherapy units. [ABSTRACT FROM AUTHOR]

Accelerated partial breast irradiation (APBI) for patients with ductal carcinoma in situ (DCIS) is controversial, and the suitability criteria from the American Brachytherapy Society (ABS), American Society of Therapeutic Radiology and Oncology (ASTRO), and the European Society for Radiotherapy and Oncology (GEC-ESTRO) have important differences. This is a single-institution retrospective review of 169 consecutive patients with DCIS who underwent lumpectomy followed by APBI intracavitary brachytherapy from 2003 to 2018. Outcomes, including overall survival, recurrence-free survival (RFS), ipsilateral breast tumor recurrence, and distant metastasis, were estimated with the Kaplan–Meier method. The median followup time was 62.5 months. Median age was 66 years (47–89 years). The majority of patients had estrogen receptor–positive disease (89%). Fifty patients (30%) had Grade 3 disease. Of the 142 patients with adequate pathology interpretation, 91 and 108 cases had margins ≥ 3 mm and ≥2 mm, respectively. Most patients (72%) were prescribed and started endocrine therapy. Of the patients evaluable for ABS criteria (N = 130), 97 met the suitability criteria. Of the patients evaluable for ASTRO criteria (N = 129), 42 were deemed cautionary and 33 were deemed unsuitable. Of the patients evaluable for GEC-ESTRO criteria (N = 143), 141 cases were at intermediate risk and two were at high risk. Five-year ipsilateral breast tumor recurrence, RFS, and overall survival were 0.6%, 97.7%, and 97.2%, respectively. The ABS, ASTRO, and GEC-ESTRO criteria failed to significantly predict for RFS. These results, although limited by short-term followup, indicate that expansion of the eligibility criteria of APBI for patients with DCIS should be considered. [ABSTRACT FROM AUTHOR]

Patient selection For boost treatments: Patients undergoing a lumpectomy as part of breast-conserving therapy can be eligible for a GammaPod boost treatment. This workflow consists of patient selection, daily quality assurance (QA), breast cup fitting, CT imaging, treatment planning, and treatment. [Extracted from the article]

Purpose: We sought to evaluate the feasibility and tolerability of a novel accelerated partial breast irradiation regimen delivered in a single fraction postoperatively.Methods and Materials: We enrolled 50 patients with low-risk, hormone-sensitive breast cancer from 2015 to 2018 on a prospective phase 1/2 trial to receive single-fraction, high-gradient partial-breast irradiation (SFHGPBI) 2 to 8 weeks after lumpectomy for node-negative, invasive, or in situ breast cancer. The high gradient was achieved by prescribing 20 Gy to the surgical bed and 5 Gy to the breast tissue within 1 cm of the surgical bed simultaneously in 1 fraction using external beam.Results: The median age was 65 (range, 52-84). Ten patients (20%) had small-volume ductal carcinoma in situ while the remainder had stage I disease. At a median follow-up of 25 months, we evaluated toxicity, patient- and physician-reported cosmesis, patient-reported quality of life (QOL), and initial tumor control. There was no Common Terminology Criteria for Adverse Events v4.0 grade 3+ toxicity. Only 34% of patients experienced grade 1 erythema. Good-to-excellent pretreatment cosmesis was present in 100% and 98% per physicians and patients, respectively, and did not change post-SFHGPBI. Quantitative cosmesis by percentage of breast retraction assessment significantly improved over time during the post-SFHGPBI period per mixed repeated measures modeling (P = .0026). QOL per European Organization for Research and Treatment of Cancer QOL Questionnaires C30 and BR-23 did not decline other than temporarily in the systemic therapy effects and hair loss domains, both of which returned to pretreatment values. There was 1 noninvasive in-breast recurrence in a separate untreated quadrant 18 months post-SFHGPBI and 1 isolated axillary recurrence 30 months post-SFHGPBI, both salvaged successfully. There were no distant recurrences or cancer-related deaths observed.Conclusions: Accelerated partial-breast irradiation delivered in a single fraction postoperatively using external beam techniques is a novel, feasible, well-tolerated regimen. SFHGPBI does not adversely affect cosmesis or QOL as reported by both physicians and patients. Initial tumor control rates are excellent, with longer follow-up required to confirm efficacy. [ABSTRACT FROM AUTHOR]

To report the achieved dosimetry in the ACCEL trial and compare the results to reported dosimetry from the major accelerated partial breast irradiation (APBI) phase III trials. The ACCEL trial was a single arm, phase II, prospective cohort study. A five-field, inverse-planned, IMRT strategy was employed using a class solution technique to increase planning consistency including high dose conformity and low normal tissue dose to the ipsilateral breast. Between 2016 and 2019, 283 patients were treated with 27 Gy in five fractions in consecutive days. The average PTV conformity index was 1.1. For the ipsilateral breast, the median (range) volume receiving 95% and 50% of the prescription dose was 9.7% (3.2–22.4) and 30.3% (11.1–54.6), respectively. Compared to major APBI phase III trial constraints, this reduction in irradiated volume at the 95% and 50% isodose levels represents a reduction of 209 cm3 and 265 cm3, respectively. The IMRT planning strategy employed in the ACCEL trial demonstrated consistent and superior dosimetry by comparison to conventionally used 3D CRT techniques. Future APBI trials should update dosimetric constraints. [ABSTRACT FROM AUTHOR]

The purpose of this study is to evaluate long-term clinical outcomes of women treated with accelerated partial breast irradiation (APBI) using multicatheter interstitial brachytherapy (MIB-APBI) with risk groups defined by Groupe Européen de Curie-thérapie and the European Society for Radiotherapy & Oncology (GEC-ESTRO), American Society for Radiation Oncology (ASTRO), updated ASTRO, and American Brachytherapy Society (ABS) guidelines and to elucidate the most appropriate guideline that could differentiate outcomes among its risk groups. Two hundred forty women underwent MIB-APBI during July 2000 to March 2013. Comparisons of long-term clinical outcomes (local control [LC], disease-free survival [DFS], cause-specific survival [CSS], and overall survival [OAS]) stratified by the risk groups proposed by the aforementioned patient selection guidelines were carried out on a prospectively maintained database. At a median follow-up of 114 months, 10-year LC, DFS, and OAS were 90%, 81%, and 83.5%, respectively, for the entire group. There was no statistically significant difference in the LC rates for risk groups by ESTRO, ASTRO, updated ASTRO and ABS guidelines. The 10-year DFS and OAS for GEC-ESTRO low-, intermediate-, and high-risk group was 75%, 88%, and 60% (p = 0.02) and 86%, 93%, and 62% (p = 0.001), respectively. Ten-year DFS and OAS in the ABS 2018–acceptable and ABS 2018–unacceptable group were 78% and 67% (p = 0.01) and 88% and 69% (p = 0.001), respectively. No significant difference in any of the outcomes was observed with risk groups suggested by ASTRO or updated ASTRO consensus guidelines. None of the current patient selection guidelines for APBI could differentiate LC (main APBI endpoint) among its risk groups, whereas GEC-ESTRO and ABS guideline could differentiate DFS and OAS. [ABSTRACT FROM AUTHOR]

Purpose: We investigate the feasibility of surface guided radiation therapy (SGRT) for accelerated partial breast irradiation (APBI) by comparing it with in‐room, fan beam kV computed tomography on rails (CTOR) imaging of the targeted region. The uniqueness of our study is that all patients have multiple daily CTOR scans to compare corresponding SGRT AlignRT (VisionRT, United Kingdom) images to. Methods/materials: Twelve patients receiving APBI were enrolled in this study. Before each treatment fraction, after patients were setup on tattoos, SGRT was performed using AlignRT, and then target matching was performance using CTOR. The average and maximum difference in shifts between SGRT and CTOR were calculated and analyzed for each patient, so as the correlation between surgical cavity size and shift difference. Results: Our study showed that SGRT agreed well with CTOR for patients with small surgical cavity volume changes (<10%). There were nine patients who had a ≥5 mm maximum shift difference between SGRT and CTOR along any direction, and in two patients the difference was more than 10 mm (one patient with surgical cavity change 44.3% and one patient with 27 cc cavity volume decrease). All patients, except one, had a mean shift difference < 5 mm along any direction. Conclusion: For the patients studied here, SGRT appears to be a reasonable and potentially valuable image guidance approach for APBI for patients who experience small changes in surgical cavity volume (<10%) between CT simulation and treatment. However, there is potential for larger alignment errors (up to 11 mm) when using SGRT for patients who experience larger surgical cavity changes. [ABSTRACT FROM AUTHOR]

To report the recurrence rates after single-fraction intraoperative electron radiotherapy (IOERT) in patients with early-stage breast cancer treated on a single institution prospective Phase I/II protocol at a community hospital. Results were retrospectively analyzed according to suitability criteria from the updated American Society for Radiation Oncology (ASTRO) consensus statement for accelerated partial breast irradiation (APBI). Patients over 40 years with early-stage invasive or in situ breast cancer (<2.5 cm and node negative) were enrolled. IOERT 2100 cGy was delivered during breast conservation surgery, and patients were followed up for a median of 3 years (0.8–6.5 years) to determine toxicity and recurrence rates. Single-fraction IOERT was performed in 215 cases (6 bilateral treatments, 196 patients) with 13 patients receiving whole-breast radiation (WBR) after IOERT for adverse pathologic features. Of 202 cases of IOERT without WBR, 89 patients experienced an ipsilateral breast tumor recurrence (IBTR) giving a cumulative incidence of 3.96%. When the ASTRO APBI suitability criteria were applied, the IBTR rate was significantly lower for suitable patients vs. cautionary or unsuitable patients (1.6% vs. 3.4% vs. 21.0%, p = 0.0002). 3-year progression-free survival after IOERT alone was 93.4%. For patients who received standard WBR (4500–5040 cGy) after IOERT, no Grade 3 or 4 toxicities (acute or late) occurred and all patients are disease-free. Single-fraction IOERT results in a low rate of IBTR when strictly adhering to ASTRO criteria for APBI suitability. Standard dose WBR for unfavorable pathologic results after 2100 cGy IOERT is well tolerated. [ABSTRACT FROM AUTHOR]

Purpose: We evaluated agreement between subjective and objective methods of cosmesis scoring in an accelerated partial breast irradiation (APBI) cohort. Material and methods: Consecutive women treated with APBI using interstitial brachytherapy reported for clinical follow-up every 6 months. Single cross-sectional assessment of the breast cosmesis was done by a radiation oncologist (subjective method) using Harvard scale and by photographic assessment using BCCT.core (Breast Cancer Conservative Treatment. Cosmetic results, version 3.1) software (objective method) at 18-36 months post-APBI. The agreement between subjective and objective methods for the overall score as well as individual subjective/objective subdomains was computed using kappa statistics. ANOVA was used to test the correlation between objective indices and subjective subdomains. Results: The agreement between the subjective (physician) and objective assessment was good with a kappa of 0.673. Overall, 77 (98.7%) patients were satisfied with the overall outcomes of breast conservation therapy. The kappa agreement between physician and patient scoring was 0.457 (95% CI: 0.240-0.674). Among the subjective subdomains, location of the nipple areola complex (NAC) had good agreement with both the overall subjective and objective score, with the kappa of 0.778 and 0.547, respectively. In the objective indices, BCE (breast compliance evaluation), LBC (lower breast contour), and UNR (unilateral nipple retraction) correlated significantly with the subjective subdomains: location of the NAC, breast size, and shape (p < 0.05 for all indices). Conclusions: Good agreement exists for overall cosmetic outcomes measured by subjective and objective methods. Location of the NAC, breast size and shape are the most important parameters determining cosmetic outcomes irrespective of the method of assessment. [ABSTRACT FROM AUTHOR]

Abstract Aim This systematic review was conducted to compare the effectiveness of different accelerated partial breast irradiation (APBI) techniques for the treatment of breast cancer patients. Background Numerous (APBI) techniques are available for clinical practice. Methods and materials Systematic review of randomized controlled trials of APBI versus whole breast irradiation (WBI). The data from APBI studies were extracted for the analyses. Indirect comparisons were used to compare different APBI techniques. Results Ten studies fulfilled the inclusion criteria. A total of 4343 patients were included, most of them with tumor stage T1-T2 and N0. Regarding APBI techniques, six trials used external beam radiation therapy; one intraoperative electrons; one intraoperative low-energy photons; one brachytherapy; and one external beam radiation therapy or brachytherapy. The indirect comparisons related to 5-years local control and 5-years overall survival were not significantly different between APBI techniques. Conclusions Based on indirect comparisons, no differences in clinical outcomes were observed among diverse APBI techniques in published clinical trials that formally compared WBI to APBI. However wide confidence intervals and high risk of inconsistency precluded a sound conclusion. Further head-to-head clinical trials comparing different APBI techniques are required to confirm our findings. Studies comparing different techniques using individual participant data and/or real-life data from population-based studies/registries could also provide more robust results. [ABSTRACT FROM AUTHOR]

• The APBI is associated with a lower average cost compared to the WBI. • There is no difference in outcome measured by QALYs at three years. • The APBI is a good option to face an increasing demand for treatments. This economic evaluation reports the incremental cost-utility ratio and national budget impact in France of accelerated partial breast irradiation (APBI) vs standard or hypofractionated whole breast irradiation (WBI) in breast cancer patients at low risk of local recurrence. We compared 490 women randomized to the APBI (ten fractions delivered twice daily over one week) with 488 women in the WBI arm (one fraction per day delivered five days per week over three or six weeks). We took the perspective of the French national health insurance with a three-year time horizon. The outcome was quality-adjusted life years (QALYs). The incremental cost-effectiveness ratio was estimated and uncertainty was explored by probabilistic bootstrapping. Transportation and sick leave costs were added in a sensitivity analysis and a national budget impact analysis based on the incidence of breast cancer estimates in France performed. At three years, the average cost per patient was €2,549 (±1,954) in the APBI arm and €4,468 (±1,586) in the WBI arm (p-value < 0.001), radiotherapy was the main driver of the difference between the two arms. No significant difference was found in QALYs. For an average of 60,000 new cases of breast cancer diagnosed annually in France, 28,000 would be eligible for treatment with APBI. A 100% uptake of APBI would result in a yearly30 million€ cost saving. APBI for the treatment of postmenopausal women with early-stage breast cancer is cost saving, with no difference in outcome measured by QALYs. [ABSTRACT FROM AUTHOR]

Purpose To improve efficiency, convenience, and cost, a prospective phase II trial was initiated to evaluate accelerated partial breast irradiation delivered with noninvasive image-guided breast brachytherapy (NIBB) via five once-daily fractions. Methods and Materials Women ≥50 years old with early-stage breast cancer undergoing breast conserving surgery were enrolled. Eligibility criteria included invasive carcinoma ≤2.0 cm or ductal carcinoma in situ ≤3.0 cm, ER positive (if invasive), lymph node negative, LVI absent, and margins negative by 2 mm. Patients received a total dose of 28.5 Gy in five daily fractions. NIBB was delivered using two orthogonal axes for each fraction. Applicators were selected to encompass the lumpectomy cavity with a 1.0 cm clinical target volume margin and 0 to 0.5 cm planning target volume margin. Acute and late toxicity was assessed based on CTCAE v3.0. Results Forty patients with a mean age of 67 years underwent protocol treatment. Mean tumor size was 1.0 cm (0.3–2.0 cm). Eighty percent had invasive carcinoma and the remainder had ductal carcinoma in situ. Mean tumor bed volume was 21 cc (5–79 cc) and mean breast volume was 1319 cc (499–3044 cc). Mean breast separation with compression was 6.7 cm (3.5–8.9 cm). All patients tolerated well. Median discomfort with compression was 1 (range: 0–7) on a 10-point pain scale. Acute skin reaction was Grade 0–1 in 70%, Grade 2 in 28%, and Grade 3 in 3%. Acute skin toxicity was not associated with breast size but was associated with larger breast separation with compression ( p < 0.01) and larger applicator size ( p < 0.01). No Grade 3+ late toxicity or local recurrences have been observed at a median followup of 14 months. Conclusions Accelerated partial breast irradiation delivered using NIBB over five daily fractions is a convenient treatment option that is feasible and well tolerated. [ABSTRACT FROM AUTHOR]

Purpose: To investigate the interobserver variations in delineation of lumpectomy cavity (LC) and clinical target volume (CTV), and its impact on irradiated volume in accelerated partial breast irradiation using intraoperative multicatheter brachytherapy. Material and methods: Delineation of LC and CTV was done by five radiation oncologists on planning computed tomography (CT) scans of 20 patients with intraoperative interstitial breast implant. Cavity visualization index (CVI), four-point index ranging from (0 = poor) to (3 = excellent) was created and assigned by observers for each patient. In total, 200 contours for all observers and 100 treatment plans were evaluated. Spatial concordance (conformity index, CIcommon, and CIgen), average shift in the center of mass (COM), and ratio of maximum and minimum volumes (Vmax/ Vmin) of LC and CTV were quantified among all observers and statistically analyzed. Variation in active dwell positions (0.5 cm step) for each catheter, total reference air kerma (TRAK), volume enclosed by prescription isodose (V100%) among observers and its spatial concordance were analyzed. Results: The mean ± SD CIcommon of LC and CTV was 0.54 ± 0.09, and 0.58 ± 0.08, respectively. Conformity index tends to increase, shift in COM and Vmax/Vmin decrease significantly (p < 0.05), as CVI increased. Out of total 309 catheters, 29.8% catheters had no change, 29.8% and 17.5% catheters had variations of 1 and 2 dwell positions (0.5 cm and 1 cm), respectively. 9.3% catheters shown variations ≥ 10 dwell positions (5 cm). The mean ± SD CIcommon of V100% was 0.75 ± 0.11. The mean observed Vmax/Vmin of prescription isodose and TRAK was 1.18 (range, 1.03 to 1.56) and 1.11 (range, 1.03 to 1.35), respectively. Conclusions: Interobserver variability in delineation of target volume was found to be significantly related to CVI. Smaller variability was observed with excellent visualization of LC. Interobserver variations showed dosimetric impact on irradiation of breast tissue volume with prescription dose. [ABSTRACT FROM AUTHOR]

Purpose: To describe early results of two cohorts of patients with low and intermediate risk of early breast cancer treated with accelerated partial breast irradiation (APBI) using different schedules of multicatheter brachytherapy. Material and methods: Patients with early stage breast cancer after breast conserving surgery were enrolled for a prospective analysis. The APBI, using multicatheter brachytherapy, was delivered either eight times 4 Gy in five days with a planned total dose of 32 Gy, or seven times 5 Gy in four days with a planned total dose of 35 Gy. Primary endpoints were side effects. Results: Forty-eight patients were enrolled between 2012 and 2014. Patients characteristics were as follow: median age of patients was 55 years, early breast cancer was defined according GEC-ESTRO recommendations. With a median follow-up period of 37 months, no significant differences regarding late side effects and cosmesis between two cohorts of patients were documented. In total, cosmesis was excellent in 13/48 (27.1%) patients, good in 34/48 (70.8%) patients, and moderate in 1/48 patient (2.1%). Conclusions: Accelerated partial breast irradiation using multicatheter brachytherapy with 32 Gy/8 fractions and 35 Gy/7 fractions for early breast cancer seems to be similar in terms of late side effects. According to our findings, APBI was also feasible for intermediate-risk of early breast cancer patients. [ABSTRACT FROM AUTHOR]

Purpose This registry trial studied the long-term outcomes of women receiving accelerated partial breast irradiation (APBI) using strut-based applicators and reports on the local control, toxicity, and survival for the first 250 patients treated with this device. Methods and Materials Patients were treated using the strut-based brachytherapy device with conventional dose and fractionation of 34 Gy in 10 twice-daily fractions. Planning goals for the planning target volume were V 90 > 90%, V 150 < 50 cc, and V 200 < 20 cc. Toxicity was graded based on the Common Terminology Criteria for Adverse Events v3.0. Recurrence rates were also calculated. Results Median followup was 59.5 months for the 250 patients. Grade 2 or higher adverse events at any time for hyperpigmentation, induration, erythema, telangiectasia, breast pain, seroma, and fat necrosis were 0.4%, 3.0%, 3.0%, 3.0%, 3.9%, 4.8%, and 1.3%, respectively. The median V 90 was 97%, V 95 was 95.1%, V 150 was 28.7 cc, and V 200 was 14.2 cc. For those patients with a less than a 5-mm or 3-mm-skin bridge, the median skin max doses were 272 and 289 cGy, respectively. The 4-year actuarial recurrence rates for true recurrence/marginal miss and ipsilateral breast tumor recurrence were 2.3% and 3.6%, respectively. The 4-year actuarial rates for overall survival, cause-specific survival, and disease-free survival were 97%, 98%, and 92%, respectively. Conclusions The strut-based applicator was designed to simplify APBI compared to interstitial brachytherapy. This report confirms excellent tumor control and survival with low toxicity and supports the evidence that brachytherapy has less normal tissue toxicity than APBI with external beam irradiation. [ABSTRACT FROM AUTHOR]

Purpose: Accelerated partial breast irradiation (APBI) using a single-lumen device is associated with better cosmetic outcomes if the spacing between the applicator and skin is > 7 mm. However, there are no reports addressing the late toxicity and clinical outcomes in patients treated with single-entry multi-lumen/catheter applicators who had close skin spacing (7 mm or less). We undertook this study to report clinical outcome, acute and late toxicity as well as cosmesis of early stage breast cancer patients with close skin spacing treated with APBI using multi-lumen or multi-catheter devices. Material and methods: This is a retrospective study of all breast cancer patients who had undergone APBI using single-entry multi-lumen/catheter devices in a single institution between 2008 to 2012. The study was limited to those with ≤ 7 mm spacing between the device and skin. Results: We identified 37 patients and 38 lesions with skin spacing of ≤ 7 mm. Seven lesions (18%) had spacing of ≤ 3 mm. Median follow-up was 47.5 months. There was one case of ipsilateral breast recurrence and one ipsilateral axillary recurrence. Based on RTOG criteria, 22 treated lesions experienced grade 1 and 9 lesions experienced grade 2 toxicity. Twenty-one lesions experienced late grade 1 toxicity. One patient had to undergo mastectomy due to mastitis. Twenty-four treated breasts showed excellent and 11 had good cosmetic outcome. Overall cosmesis trended towards a significant correlation with skin spacing. However, all patients with ≤ 3 mm skin spacing experienced acute and late toxicities. Conclusions: Accelerated partial breast irradiation can be safely performed in patients with skin spacing of ≤ 7 mm using single-entry multi-lumen/catheter applicators with excellent cosmetic outcomes and an acceptable toxicity profile. However, skin spacing of ≤ 3 mm is associated with acute and late toxicity and should be avoided if possible. [ABSTRACT FROM AUTHOR]

Multiple adjuvant radiation therapy options currently exist for women following breast-conserving surgery including standard fractionated whole breast irradiation (WBI), accelerated whole breast irradiation (AWBI), and accelerated partial breast irradiation (APBI). The recent publication of several randomized trials comparing APBI to standard WBI provides Level I evidence supporting APBI. The purpose of this review is to summarize the Level I data supporting APBI in an effort to provide guidance when to offer this treatment approach vs. standard WBI, AWBI, or excision alone and to address questions related to its application. Four contemporary trials with over 2000 patients comparing APBI and WBI have been published and demonstrate no differences in the rates of local/regional recurrence or survival though long-term followup is limited to one study. In addition, reductions in the rates of acute and chronic toxicity and improvements in cosmetic outcome were noted in two of these trials (the University of Florence and the Hungarian Phase III trials, respectively). When contrasting other treatment approaches to APBI, patients treated in studies using AWBI have many comparable clinical and pathologic characteristics, whereas studies investigating endocrine therapy alone (surgery with no adjuvant radiation therapy) have much “lower risk” patients based on clinical, pathologic, and treatment-related criteria. Although significant Level I evidence now exists supporting the use of APBI as an alternative to WBI in selected patients undergoing breast-conserving therapy, additional data are needed to ( 1 ) help further refine patient selection criteria, ( 2 ) better clarify the optimal partial breast irradiation target and technique for each clinical setting, ( 3 ) determine when AWBI, standard WBI, or excision alone may be more appropriate, and ( 4 ) investigate if further reductions in fractionation schedules are possible. [ABSTRACT FROM AUTHOR]

Purpose Current guidelines for high-dose-rate accelerated partial breast irradiation using single-entry implants are based on the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol, which assumed a balloon implant geometry. We have developed robust plan evaluation criteria specifically for the strut-adjusted volume implant (SAVI). Methods and Materials Plan evaluation criteria were established using a “training data set” of 62 SAVI treatment plans and included the percentage volume of target receiving 90%, 95%, and 100% of the prescription dose ( V 90 , V 95 , and V 100 ), the absolute volume of target receiving 150% and 200% of prescription ( V 150 and V 200 ), and the maximum doses to skin ( D skin max ) and ribs ( D rib max ). “Ideal” and “expected” (routinely achievable) thresholds were determined for each criterion and compared to B-39 guidelines. A “test data set” collected from the next 25 patients was analyzed using the developed plan evaluation criteria. Results Ideal (expected) dosimetric thresholds established from the training data set were V 90 ≥ 98% (95%), V 95 ≥ 95% (92%), V 100 ≥ 91% (88%), D skin max < 90% (100%), and D rib max < 100%. Thresholds for V 150 and V 200 were stratified by SAVI size: V 150 ≤ 30 cc (50 cc) and V 200 ≤ 15 cc (20 cc) for 6–1 and Mini; V 150 ≤ 50 cc (50 cc) and V 200 ≤ 20 cc (20 cc) for 8–1 and 10–1. There was no significant difference between the training and test data sets in the fractions of patients meeting the criteria. Overall, 58% and 95% of 87 plans met all ideal and all expected criteria, respectively. Conclusions The plan evaluation criteria developed specifically for the SAVI device are robust, providing increased target coverage and increased skin sparing compared to B-39 guidelines. [ABSTRACT FROM AUTHOR]

Purpose: The efficacy of accelerated partial breast irradiation (APBI) utilizing brachytherapy or conventional external beam radiation has been studied in early-stage breast cancer treated with breast-conserving surgery. Data regarding stereotactic treatment approaches are emerging. The CyberKnife linear accelerator enables excellent dose conformality to target structures while adjusting for target and patient motion. We report our institutional experience on the technical feasibility and rationale for stereotactic accelerated partial breast irradiation (SAPBI) delivery using the CyberKnife radiosurgery system. Methods: Ten patients completed CyberKnife SAPBI (CK-SAPBI) in 2013 at Georgetown University Hospital. Four gold fiducials were implanted around the lumpectomy cavity prior to treatment under ultrasound guidance. The synchrony system tracked intrafraction motion of the fiducials. The clinical target volume was defined on contrast enhanced CT scans using surgical clips and post-operative changes. A 5 mm expansion was added to create the planning treatment volume (PTV). A total dose of 30 Gy was delivered to the PTV in five consecutive fractions. Target and critical structure doses were assessed as per the National Surgical Adjuvant Breast and Bowel Project B-39 study. Results: At least three fiducials were tracked in 100% of cases. The Mean treated PTV was 70 cm² and the mean prescription isodose line was 80%. Mean dose to target volumes and constraints are as follows: 100% of the PTV received the prescription dose (PTV30). The volume of the ipsilateral breast receiving 30 Gy (V30) and above 15 Gy (V > 15) was 14 and 31%, respectively. The ipsilateral lung volume receiving 9 Gy (V9) was 3%, and the contralateral lung volume receiving 1.5 Gy (V1.5) was 8%. For left-sided breast cancers, the volume of heart receiving 1.5 Gy (V1.5) was 31%. Maximum skin dose was 36 Gy. At a median follow-up of 1.3 years, all patients have experienced excellent/good breast cosmesis outcomes, and no breast events have been recorded. Conclusion: CyberKnife stereotactic accelerated partial breast irradiation is an appealing technique for partial breast irradiation offering improvements over existing APBI techniques. Our early findings indicate that CK-SAPBI delivered in five daily fractions is feasible, well tolerated, and is reliable platform for delivering APBI. [ABSTRACT FROM AUTHOR]

Purpose: The use of multicatheter interstitial brachytherapy (MIB) for accelerated partial breast irradiation (APBI) in early breast cancer (EBC) patients outside the trial setting has increased. Hence, there is a need to critically evaluate implant quality. Moreover, there is a scarcity of reports using an open cavity technique. We report the dosimetric indices of open and closed cavity MIB techniques. Material and methods: The dosimetric parameters of 60 EBC patients treated with MIB (open and closed cavity) who underwent three dimensional, computerized tomography (CT) based planning for APBI from November 2011 to July 2015 were evaluated. Coverage Index (CI), Dose Homogeneity Index (DHI), Conformity Index (COIN), Plan Quality Index (PQI), and Dose Non-uniformity Index (DNR) were assessed. Results: Forty-one patients underwent open cavity and 19 patients underwent closed cavity placement of brachytherapy catheters. The median number of planes was 4 and median number of needles was 20. Median dose was 34 Gy with dose per fraction of 3.4 Gy, given twice a day, 6 hours apart. The D90 of the cavity and clinical target volume (CTV) were 105% and 89%, respectively. The median doses to the surgical clips were greater than 100%. The median CI of the cavity and CTV was 0.96 and 0.82, respectively. The DHI and COIN index of the CTV was 0.73 and 0.67. There were no significant differences in the dosimetric parameters based on whether the technique was done open or closed. Conclusions: Critical evaluation of the dosimetric parameters of MIB-APBI is important for optimal results. While the open and closed techniques have similar dosimetry, our institutional preference is for an open technique which eases the procedure due to direct visualization of the tumor cavity. [ABSTRACT FROM AUTHOR]

Accelerated partial breast irradiation (APBI) represents an evolving technique that is a standard of care option in appropriately selected woman following breast conserving surgery. While multiple techniques now exist to deliver APBI, interstitial brachytherapy represents the technique used in several randomized trials (National Institute of Oncology, GEC-ESTRO). More recently, many centers have adopted applicator-based brachytherapy to deliver APBI due to the technical complexities of interstitial brachytherapy. The purpose of this article is to review methods to evaluate and select patients for APBI, as well as to define potential workflow mechanisms that allow for the safe and effective delivery of APBI. Multiple consensus statements have been developed to guide clinicians on determining appropriate candidates for APBI. However, recent studies have demonstrated that these guidelines fail to stratify patients according to the risk of local recurrence, and updated guidelines are expected in the years to come. Critical elements of workflow to ensure safe and effective delivery of APBI include a multidisciplinary approach and evaluation, optimization of target coverage and adherence to normal tissue guideline constraints, and proper quality assurance methods. [ABSTRACT FROM AUTHOR]

Purpose: To determine differences in patient's reported quality of life and self-reported breast cosmesis between whole breast radiation therapy (WBRT) and accelerated partial breast irradiation (APBI) via single and multi-lumen high-dose-rate (HDR) brachytherapy for women with early stage breast cancer. Material and methods: Patient information was retrospectively reviewed and survey data were prospectively collected for women treated between 2004 to 2014 (APBI) and 2012 to 2014 (WBRT). Criteria for APBI treatments were ER+ (after 2010), N0 (after 2010), T < 3 cm, and post-menopausal. All patients were given a survey with modified FACIT (Functional Assessment of Chronic Illness Therapy) breast quality of life questions to rate their amount of pain, self-consciousness, low energy, presence of lymphedema, and breast cosmesis. Results: 242 APBI patients and 59 WBRT patients were identified. In the WBRT cohort, 34 women met departmental criteria for APBI treatment (WBRT who were APBI eligible). The FACIT survey was completed by 80 women treated with APBI (33%; mean follow-up time of 14 months), and 26 women treated with WBRT who were APBI eligible (76%; mean follow-up time of 26 months). During the first year post-treatment, low energy (p = 0.009), self-consciousness (p = 0.0004), and lymphedema (p = 0.0002) scores were significantly lower in the APBI cohort when compared to women treated with WBRT who were APBI eligible. During the second year post-treatment, women treated with APBI reported significantly better breast cosmesis (p = 0.04). The single-lumen balloon (score = 6.3/10) was found to be associated with worse cosmesis compared to the multi-lumen balloons (Mammosite ML and Contura; score = 8.2/10; p = 0.002). There were no significant differences in rates of recurrence between balloons or treatments (p > 0.05). Conclusions: APBI treated patients reported higher cosmetic satisfaction than patients in the matched WBRT cohort. Quality of life scores tended to improve over time. Multi-lumen catheters provided superior cosmetic results compared to single-lumen catheters. [ABSTRACT FROM AUTHOR]

Purpose Brachytherapy-based APBI (bAPBI) shortens treatment duration and limits dose to normal tissue. While studies have demonstrated similar local control when comparing bAPBI and whole breast irradiation using intensity modulated radiotherapy (WBI-IMRT), comparison of late side effects is limited. Here, we report chronic toxicity profiles associated with these two treatment modalities. Methods 1034 patients with early stage breast cancer were treated at a single institution; 489 received standard-fractionation WBI-IMRT between 2000 and 2013 and 545 received bAPBI (interstitial 40%, applicator-based 60%) between 1993 and 2013. Chronic toxicity was evaluated ≥6 months utilizing CTCAE version 3.0; cosmesis was evaluated using the Harvard scale. Results Median follow-up was 4.6 years (range 0.1–13.4) for WBI-IMRT versus 6.7 years (range 0.1–20.1) for bAPBI (p < 0.001). Compared to WBI-IMRT, bAPBI was associated with higher rates of ≥grade 2 seroma formation (14.4% vs 2.9%, p < 0.001), telangiectasia (12.3% vs 2.1%, p = 0.002) and symptomatic fat necrosis (10.2% vs 3.6%, p < 0.001). Lower rates of hyperpigmentation were observed (5.8% vs 14.5%; p = 0.001). Infection rates were similar (3.3% vs 1.3%, p = 0.07). There was no difference between rates of fair (6.1% vs. 4.1%, p = 0.30) or poor (0.2% vs. 0.5%, p = NS) cosmesis. Mastectomy rates for local recurrence (3.1% for WBI-IMRT and 1.2% for bAPBI, p = 0.06), or for other reasons (0.8% and 0.6%, p = 0.60) were similar between groups. Conclusion With 5-year follow-up, WBI-IMRT and bAPBI are associated with similar, acceptable rates of toxicity. These data further support the utilization of bAPBI as a modality to deliver adjuvant radiation in a safe and efficacious manner. [ABSTRACT FROM AUTHOR]

Purpose Noninvasive image-guided breast brachytherapy (NIBB) is an attractive novel approach to deliver accelerated partial breast irradiation (APBI). Calculations of equivalent uniform dose (EUD) were performed to identify the appropriate APBI dose for this technique. Methods and Materials APBI plans were developed for 15 patients: five with three-dimensional conformal APBI (3D-CRT), five with multi-lumen intracavitary balloons (m-IBB), and five simulating NIBB treatment. Prescription doses of 34.0 and 38.5 Gy were delivered in 10 fractions for m-IBB and 3D-CRT, respectively. Prescription doses ranging from 34.0 to 38.5 Gy were considered for NIBB. Dose-volume histogram data from all 3D-CRT, m-IBB, and NIBB plans were used to calculate the biologically effective EUD and corresponding EUD to the PTV_eval using the following equation: EUD = EUBED/(n [1 + EUD/α/β]). An α/β value of 4.6 Gy was assumed for breast tumor. EUD for varying NIBB prescription doses were compared with EUD values for the other APBI techniques. Results Mean PTV_eval volume was largest for 3D-CRT (372.9 cm 3 ) and was similar for NIBB and m-IBB (88.7 and 87.2 cm 3 , respectively). The EUD value obtained by prescribing 38.5 Gy with 3D-CRT APBI was 38.6 Gy. The EUD value of 34.0 Gy prescribed with m-IBB was 34.4 Gy. EUD values for NIBB ranged from 33.9 to 38.2 Gy for prescription doses ranging from 34.0 to 38.5 Gy. Conclusions Using EUD calculations to compare APBI techniques and treatment doses, a prescription dose of 36.0 Gy in 10 fractions using NIBB has a comparable biologic equivalent dose to other established brachytherapy techniques. [ABSTRACT FROM AUTHOR]

Purpose In July 2009, American Society of Radiation Oncology (ASTRO) released a consensus statement (CS) to guide patient selection for accelerated partial breast irradiation (APBI). The goal of this study was to examine how practice patterns changed following the guideline's release. Methods The Surveillance, Epidemiology, and End Results database was queried from 2008 to 2010 for females aged ≥20 years receiving breast conservation via brachytherapy. Among the APBI cohort, characteristics and CS grouping (“suitable,” “cautionary,” or “unsuitable”) of patients receiving APBI in the 18 months before (January 2008 to June 2009) and after (July 2009 to December 2010) guideline publication were analyzed. Results A total of 87,528 patients undergoing breast conservation therapy were identified. Of this, 4,253 patients (4.9%) received brachytherapy-based APBI. Limiting the analysis to patients not missing data that would affect their CS classification rendered 3,828 patients. The proportion of breast conservation patients receiving brachytherapy-based APBI before and after CS release remained the same (4.9% vs. 4.8%, p = 0.36). Among patients receiving brachytherapy-based APBI, the unsuitable category decreased (15.8 vs. 11.1%, p < 0.01), whereas the suitable category increased (37.7% vs. 42.1%, p = 0.03), and the cautionary category was stable (46.5% vs. 46.7% p = 0.90) after guideline publication. Joinpoint regression analysis failed to reveal that the changes in practice patterns corresponded with the CS publication date. Conclusions The period before and after publication of the ASTRO CS was associated with a decrease in “unsuitable” patients and an increase in “suitable” patients being treated with brachytherapy-based APBI. This trend began before guideline release and thus cannot be definitively attributed to the ASTRO CS. [ABSTRACT FROM AUTHOR]

Purpose: Currently, there are two described methods of catheter insertion for women undergoing multicatheter interstitial accelerated partial breast irradiation (APBI). These are a volume based template approach (template) and a non-template ultrasound guidance freehand approach (non-template). We aim to compare dosimetric endpoints between the template and non-template approach. Material and methods: Twenty patients, who received adjuvant multicatheter interstitial APBI between August 2008 to March 2010 formed the study cohort. Dosimetric planning was based on the RTOG 04-13 protocol. For standardization, the planning target volume evaluation (PTV-Eval) and organs at risk were contoured with the assistance of the attending surgeon. Dosimetric endpoints include D90 of the PTV-Eval, Dose Homogeneity Index (DHI), V200, maximum skin dose (MSD), and maximum chest wall dose (MCD). A median of 18 catheters was used per patient. The dose prescribed was 34 Gy in 10 fractions BID over 5 days. Results: The average breast volume was 846 cm³ (526-1384) for the entire cohort and there was no difference between the two groups (p = 0.6). Insertion time was significantly longer for the non-template approach (mean 150 minutes) compared to the template approach (mean: 90 minutes) (p = 0.02). The planning time was also significantly longer for the non-template approach (mean: 240 minutes) compared to the template approach (mean: 150 minutes) (p < 0.01). The template approach yielded a higher D90 (mean: 95%) compared to the non-template approach (mean: 92%) (p < 0.01). There were no differences in DHI (p = 0.14), V200 (p = 0.21), MSD (p = 0.7), and MCD (p = 0.8). Conclusions: Compared to the non-template approach, the template approach offered significant shorter insertion and planning times with significantly improved dosimetric PTV-Eval coverage without significantly compromising organs at risk dosimetrically. [ABSTRACT FROM AUTHOR]

Breast-conserving therapy (BCT) represents the standard care in the management of early-stage breast cancer, because long-term outcomes with breast conservation are comparable with those of mastectomy. Adjuvant radiation therapy remains an essential component of BCT with standard techniques requiring 5-6½ weeks. Accelerated partial breast irradiation (APBI) is a technique developed over the past two decades that enables completion of treatment in one week or less. Review of the expanding literature reveals increasing support for APBI using several techniques, including interstitial brachytherapy, balloon-based brachytherapy, and external beam therapy. Novel treatment strategies, including intraoperative radiation therapy, hypofractionated APBI, and proton therapy, require further results before definitive conclusions can be made. Although there is currently a lack of level I evidence, with the pending publication of multiple phase III trials comparing whole-breast irradiation and APBI, modern treatment incorporating APBI should soon be developed. [ABSTRACT FROM AUTHOR]

Accelerated partial breast irradiation (APBI) is an alternative to receiving whole breast radiation in carefully selected patients. Because breast cancer local recurrence rates are low and follow-up has been short-term, the exact cause of recurrences after APBI has been difficult to evaluate. We report the first case of documented radiation balloon catheter malpositioning that resulted in local recurrence. Patients undergo CT imaging of the breast after radiation balloon catheter placement for radiotherapy treatment planning, which evaluates adequate conformance of the balloon to the surrounding breast parenchyma and confirms a >7 mm distance between the balloon surface and the skin surface. Although true local recurrences are rare in appropriately selected partial breast irradiation candidates, inadvertent malpositioning of the radiation treatment catheter can increase the risk. This case is presented to illustrate the importance of comparing CT radiation planning images, with treatment catheter in place, to the original diagnostic breast imaging studies to confirm proper catheter positioning (in addition to measuring balloon to skin distance and conformance) prior to initiating radiotherapy. [ABSTRACT FROM AUTHOR]

Abstract: Purpose: To review the initial experience of three institutions using multilumen catheters to deliver accelerated partial breast irradiation (APBI) and evaluate dosimetric improvements. Methods and Materials: Patients were eligible for this analysis if they met criteria for accelerated partial breast irradiation at their respective institution and were not enrolled on the national Phase III trial. Minimum guidelines for treatment planning from the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol were followed. Toxicities were coded using common toxicity criteria version 3.0 criteria. Results: Sixty-two patients were analyzed as part of this study. Median skin spacing was 11mm with a median skin dose of 86.9% (% of prescription dose [PD]). Median rib dose was 76.1% of the PD (range, 4.3–155.7%). The V 90, V 95, and V 100 of the PD for the planning target volume evaluation was 95.4%, 95.2%, and 80.3%, respectively. Seven patients had both skin and rib spacing <7mm, with the median skin dose and rib dose being 113.4% and 130.9% of the PD. For these cases, the median V 90, V 95, and V 100 of the PD was 99.2%, 94.3%, and 81.1%, respectively, whereas the median V 150 and V 200 were 22.5cc and 7.4cc. Overall, Grade I and II radiation dermatitis were noted in 41.9% and 6.5% of patients. Conclusion: The multilumen device led to improvements in target coverage and normal structure doses compared with traditionally accepted guidelines. Similar toxicities were seen compared with single-lumen devices, even in patients with skin and rib spacing <7mm. [Copyright &y& Elsevier]

Abstract: Background and Purpose: To compare 12-year outcomes of accelerated partial breast irradiation (APBI) versus whole-breast irradiation (WBI) in patients treated with breast conservation. Materials and Methods: A matched-pair analysis was performed using 199 patients receiving WBI and 199 patients receiving interstitial APBI. Match criteria included tumor size, age, nodal status, ER status, and the use of adjuvant hormonal therapy. Patterns of failure and efficacy of salvage treatments were examined. Results: No differences were seen in the 12-year rates of local recurrence (3.8% vs. 5.0%, p =0.40), regional recurrence (0% vs. 1.1%, p =0.15), disease free survival (DFS) (87% vs. 91%, p =0.30), cause-specific survival (CSS) (93% vs. 95%, p =0.28), or overall survival (OS) (78% vs. 71%, p =0.06) between the WBI and APBI groups, respectively. The rate of distant metastases was lower in the APBI group (10.1% vs. 4.5%, p =.05). Following LR, no difference in outcome was seen between the two groups with 5year post-LR rates of DFS (80% vs. 86%, p =0.55), CSS (88% vs. 75%, p =0.77), and OS (88% vs. 75%, p =0.77), respectively. Conclusions: With 12-year follow-up, APBI produced outcomes equivalent to WBI. Following LR, patients treated with APBI also had similar failure patterns to those managed with WBI. [Copyright &y& Elsevier]

Purpose: This study investigated the magnitude of intrafractional motion and level of accuracy of various setup strategies in accelerated partial breast irradiation (APBI) using three-dimensional conformal external beam radiotherapy. Methods and Materials: At lumpectomy, gold fiducial markers were strategically sutured to the surrounding walls of the cavity. Weekly fluoroscopy imaging was conducted at treatment to investigate the respiration-induced target motions. Daily pre- and post-RT kV imaging was performed, and images were matched to digitally reconstructed radiographs based on bony anatomy and fiducial markers, respectively, to determine the intrafractional motion magnitudes over the course of treatment. The positioning differences of the laser tattoo- and the bony anatomy-based setups compared with those of the marker-based setup (benchmark) were also determined. The study included 21 patients. Results: Although lung exhibited significant motion, the average marker motion amplitude on the fluoroscopic image was about 1 mm. Over a typical treatment time period, average intrafractional motion magnitude was 4.2 mm and 2.6 mm based on the marker and bony anatomy matching, respectively. The bony anatomy- and laser tattoo-based interfractional setup errors, with respect to the fiducial marker-based setup, were 7.1 and 9.0 mm, respectively. Conclusions: Respiration has limited effects on the target motion during APBI. Bony anatomy-based treatment setup improves the accuracy relative to that of the laser tattoo-based setup approach. Since fiducial markers are sutured directly to the surgical cavity, the marker-based approach can further improve the interfractional setup accuracy. On average, a seroma cavity exhibits intrafractional motion of more than 4 mm, a magnitude that is larger than that which is otherwise derived based on bony anatomy matching. A seroma-specific marker-based approach has the potential to improve treatment accuracy by taking the true inter- and intrafractional motions into consideration. [Copyright &y& Elsevier]

Purpose: To evaluate with a randomized clinical trial the possibility of treating the index quadrant with external intensity-modulated radiotherapy (IMRT) in a selected group of patients with early-stage breast cancer and to analyze the acute toxicity. Methods and Materials: From September 2005, a randomized Phase III clinical trial has been conducted to compare conventional (tangential field) fractionated whole breast treatment (Arm A) with accelerated partial breast irradiation plus intensity-modulated radiotherapy (Arm B). For intensity-modulated radiotherapy, the clinical target volume was drawn with a uniform 1-cm margin around the surgical clips in three dimensions. The ipsilateral and contralateral breast, ipsilateral and contralateral lung, heart, and spinal cord were contoured as organs at risk. All the regions of interest were contoured according to the International Commission on Radiation Units and Measurements reports 50 and 62 recommendations. Results: In September 2008, 259 patients were randomized and treated. The mean clinical target volume in Arm B was 44 cm3 and the mean planning target volume was 123 cm3. The mean value of the ratio between the planning target volume and the ipsilateral breast volume was 21%. The rate of Grade 1 and Grade 2 acute skin toxicity was 22% and 19% in Arm A (Radiation Therapy Oncology Group scale), respectively. The tolerance in Arm B was excellent with only 5% Grade 1 and 0.8% Grade 2 acute skin toxicity. The planning constraints were fully satisfied in most patients. In a very few cases, this was not possible because of very unfavorable anatomy. Quality assurance procedures were performed according to our internal quality assurance protocol, with excellent results. Conclusion: In the present preliminary analysis, we have demonstrated that accelerated partial breast irradiation is feasible, with very low acute toxicity. [Copyright &y& Elsevier]

Purpose: To assess the incidence and severity of late normal tissue toxicity using three-dimensional conformal radiotherapy to deliver accelerated partial breast irradiation. Methods and Materials: A total of 60 patients were treated with three-dimensional conformal radiotherapy for accelerated partial breast irradiation. Treatment planning and delivery were in strict accordance with the technique and specified dose–volume constraints of the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol. Late toxicity was evaluated according to the Radiation Therapy Oncology Group grading schema. The cosmetic outcome was scored using the Harvard criteria. Univariate logistic regression analysis was performed to evaluate the correlation of dosimetric variables with outcome. Results: At a median follow-up of 15 months, moderate-to-severe late toxicity developed in 10% of patients. The most pronounced late toxicity was subcutaneous fibrosis: 25% Grade 2-4 and 8.3% Grade 3-4. The modified planning tumor volume/whole breast volume ratio, ratio of the volume of breast tissue receiving 5%, 20%, 50%, and 80% of the prescription dose to the whole breast volume, and maximal dose within the breast correlated with the development of fibrosis (p = .10, p = .03, p = .04, p = .06, p = .09, and p = .046, respectively). The overall cosmetic outcome was good to excellent in 81.7%, fair in 11.7%, and poor in 6.7%. The presence of subcutaneous fibrosis, modified planning tumor volume/whole breast volume ratio, ratio of the volume of breast tissue receiving 5% and 20% of the prescription dose to the whole breast volume, and pathologic specimen volume correlated with the risk of a fair/poor cosmetic outcome (p < .001, p = .02, p = .05, p = .04, p = .01, respectively). Conclusion: The three-dimensional conformal radiotherapy technique for accelerated partial breast irradiation as specified in the National Surgical Adjuvant Breast and Bowel Project B-39/Radiation Therapy Oncology Group 0413 protocol resulted in a remarkably high rate of moderate-to-severe late normal tissue effects, despite the relatively brief follow-up period. The toxic events correlated clearly with several dose–volume parameters. [Copyright &y& Elsevier]

Purpose: To report the local control and overall survival outcomes after lumpectomy followed by accelerated partial breast irradiation in high-risk patients as defined by the current inclusion criteria for the National Surgical Adjuvant Breast and Bowel B-39/Radiation Therapy Oncology Group 0413 Intergroup trial. Methods and Materials: Between 2000 and 2005, 273 women with early-stage breast cancer were treated using either multicatheter interstitial brachytherapy (n = 247) or MammoSite (n = 26). Patients received 32–34 Gy in 8–10 twice-daily fractions using high-dose-rate 192Ir brachytherapy. All patients met the initial inclusion criteria for the Intergroup trial and were separated into two groups: high-risk patients (representing the cohort that remained eligible for the Intergroup trial) who satisfied one or more of the “high-risk” criteria (age <50 years, estrogen receptor negative, and/or positive lymph nodes; n = 90), and low-risk patients who comprised the remainder of the cohort (n = 183). The outcomes of the two cohorts were analyzed and compared. Results: The median follow-up of the entire cohort was 48.5 months. No significant difference was found in outcomes at 5 years between the low- and high-risk groups, with a local control rate of 97.8% vs. 93.6%, crude local recurrence rate of 2.2% (n = 4) vs. 4.4% (n = 4), and overall survival rate of 92.1% vs. 89.5%, respectively. Conclusion: At 5 years, no statistically significant difference was found in outcomes for patients deemed to be at greater risk in the current National Surgical Adjuvant Breast and Bowel B-39/Radiation Therapy Oncology Group 0413 Intergroup trial. These clinical data support the inclusion of this “high-risk” population in this important ongoing study. [Copyright &y& Elsevier]