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Background Postmastectomy radiotherapy (PMRT) with TomoHelical™ (TH) or TomoDirect™ (TD) allows a uniform target coverage. In this study, we compare treatment plans using TD and TH in the setting of hypofractionated PMRT and immediate breast reconstruction. Material and methods The TD-treatment plans of breast cancer patients treated between May 2016 and August 2019 were retrospectively selected. All the TD plans were re-planned on TH with the same prescription dose (40.05 Gy/15 fractions) and according to our dose/volume constraints. Data about the 2 treatment plans were compared with a focus on PTV coverage and all the organs at risk (OARs) constraints. Results Fifty patients for a total number of 100 treatment plans (50 with TD and 50 re-planned with TH) were analyzed. All the median value in the TD PTV CHEST WALL plans fulfilled the predefined planning objectives, even though TH emerged as best for target coverage with statistically significant difference for V90%. TD provided the lowest V95% for the PTV SVC, but the median value was near to the recommended value of 90% (89.8 % vs 98.6% for TD and TH, respectively). Overall, TD reached the best OARs sparing. The main statistically significant differences with TH were for contralateral breast, ipsilateral and contralateral lung. All the other dose values for TH were higher than TD, but they fulfilled the recommended/acceptable predefined planning objectives. Conclusions In the setting of PMRT, TD compared to TH reached an acceptable target volume coverage, with an optimal sparing of OARs.

Aims: To report toxicity of a hypofractionated scheme of whole-breast (WB) intensity-modulated radiotherapy (IMRT) with simultaneous integrated boost (SIB) to the tumor bed (TB) using Tomotherapy® with Direct modality. Methods: Patients with early breast cancer, undergoing radiotherapy (RT) in 15 daily fractions to WB (prescription dose 40.05 Gy) and SIB to the TB (48 Gy), between 2013 and 2017, was analyzed. Primary endpoint was acute and intermediate toxicity assessed at the end and within 6 months from RT, according to Radiation Therapy Oncology Group (RTOG) scale. Secondary endpoints included early chronic toxicity at 12-months follow-up, using the Late Effects Normal Tissue Task Subjective, Objective, Management, and Analytic (LENT-SOMA) scale, and cosmesis using Harvard criteria. Results: The study population was of 287 patients. Acute and intermediate toxicity was collected among 183 patients with data available at the end of RT and within 6 months, 85 (46%) experienced G2 toxicity and 84 (46%) G1 toxicity, while 14 (8%) did not report toxicity at any time. A significant reduction of any grade toxicity was observed between the two time points, with the majority of patients reporting no clinically relevant toxicity at 6 months. At univariate analysis, age < 40 years, breast volume > 1000 cm3 and Dmax ≤ 115% of prescription dose were predictive factors of clinically relevant acute toxicity (G ≥ 2) at any time. At multivariable analysis, only age and breast volume were confirmed as predictive factors, with Relative Risks (95% Confidence Intervals): 2.02 (1.13–3.63) and 1.84 (1.26–2.67), respectively. At 12-month follow-up, 113 patients had complete information on any toxicity with 53% of toxicity G < 2, while cosmetic evaluation, available for 102 patients, reported a good–excellent result for 86% of patients. Conclusions: Hypofractionated WB IMRT with a SIB to the TB, delivered with TomoDirect modality, is safe and well-tolerated. Most patients reported no toxicity after 6 months and good–excellent cosmesis. Predictive factors of clinically relevant toxicity might be considered during treatment planning in order to further reduce side effects.

Background Tellurium is a rare metalloid that exerts high toxicity on cells, especially on bacteria, partly due to reactive oxygen species (ROS) generation. Moreover, it has also been observed that tellurite can target free cell thiols groups (RSH) (i.e. reduced glutathione (GSH)), enhancing the cellular redox imbalance. Additionally, in vitro experiments have suggested that several enzymes can reduce tellurite (IV) to its elemental form (0); where RSH present on their active sites may be responsible for the process. Nevertheless, the mechanisms implemented by bacteria for tellurite reduction and its role in resistance have not been evaluated in vivo. Results This work shows that tellurite reduction to elemental tellurium is increased under anaerobic conditions in E. coli cells. The in vivo tellurite reduction is related to the intracellular concentration of total RSH, in the presence and absence of oxygen. This metabolization of tellurite directly contributes to the resistance of the bacteria to the oxyanion. Conclusions We demonstrated that in vivo tellurite reduction is related to the intracellular thiol concentration, i.e. large availability of cellular RSH groups, results in a more significant reduction of tellurite. Furthermore, we observed that, when the bacterium exhibits less resistance to the oxyanion, a decreased tellurite reduction was seen, affecting the growth fitness. Together, these results let us propose that tellurite reduction and the intracellular RSH content are related to the oxyanion bacterial resistance, this tripartite mechanism in an oxygen-independent anaerobic process.

Objectives: To determine interobserver variability in axillary nodal contouring in breast cancer (BC) radiotherapy (RT) by comparing the clinical target volume of participating single centres (SC-CTV) with a gold-standard CTV (GS-CTV). Methods: The GS-CTV of three patients (P1, P2, P3) with increasing complexity was created in DICOM format from the median contour of axillary CTVs drawn by BC experts, validated using the simultaneous truth and performance-level estimation and peer-reviewed. GS-CTVs were compared with the correspondent SC-CTVs drawn by radiation oncologists, using validated metrics and a total score (TS) integrating all of them. Results: Eighteen RT centres participated in the study. Comparative analyses revealed that, on average, the SC-CTVs were smaller than GS-CTV for P1 and P2 (by −29.25% and −27.83%, respectively) and larger for P3 (by +12.53%). The mean Jaccard index was greater for P1 and P2 compared to P3, but the overlap extent value was around 0.50 or less. Regarding nodal levels, L4 showed the highest concordance with the GS. In the intra-patient comparison, L2 and L3 achieved lower TS than L4. Nodal levels showed discrepancy with GS, which was not statistically significant for P1, and negligible for P2, while P3 had the worst agreement. DICE similarity coefficient did not exceed the minimum threshold for agreement of 0.70 in all the measurements. Conclusions: Substantial differences were observed between SC- and GS-CTV, especially for P3 with altered arm setup. L2 and L3 were the most critical levels. The study highlighted these key points to address. Advances in knowledge The present study compares, by means of validated geometric indexes, manual segmentations of axillary lymph nodes in breast cancer from different observers and different institutions made on radiotherapy planning CT images. Assessing such variability is of paramount importance, as geometric uncertainties might lead to incorrect dosimetry and compromise oncological outcome.

Aim To evaluate reconstruction failure (RF) rate in patients receiving implant-based immediate breast reconstruction (IBR) and hypofractionated (HF) postmastectomy radiation therapy (PMRT). Materials and methods Stage II–III breast cancer patients, treated with HF-PMRT using intensity modulated radiotherapy were stratified in two groups according to IBR: single-stage direct-to-implant (DTI-group) and two-stage expander and implant (TE/I-group). Irradiated patients were matched with non-irradiated ones who underwent the same IBR during the same period. Prescription dose was 40.05 Gy/15 fractions to chest wall and infra/supraclavicular nodal region. Primary endpoint was RF defined as the need of major revisional surgery (MaRS) for implant removal or conversion to autologous reconstruction. Secondary endpoint was the rate of minor revisional surgeries (MiRS) including implant repositioning or substitution with another implant. Results One hundred and seven irradiated patients (62 in TE/I-group, 45 in DTI-group) were matched with 107 non-irradiated subjects. Median follow-up was 4.2 years (0.1–6.1) In the TE/I setting, MaRS was performed in 8/62 irradiated patients (12.9%) of the irradiated TE/I group compared to 1/62 (1.6%) non-irradiated subjects (p = 0.015). In the DTI setting, MaRs occurred in 3/45 irradiated patients (6.7%) compared to 1/45 non-irradiated ones (2.2%) (p = 0.35). Overall MaRS rate was 10.3% in the irradiated group. MiRS was performed in 35.6% and 31.1% of the irradiated and non-irradiated DTI-groups (p = 0.65), respectively, and in 12.9% and 8.1% of the irradiated and non-irradiated TE/I groups (p = 0.38), respectively. Conclusions Compared to the non-irradiated counterparts, the TE/I group showed higher rate of RF, while no statistically significant difference was observed for the DTI group. The use of hypofractionation and IMRT to implant-based IBR did not seem to increase the risk of RF which appeared to be in line with the literature

Additional file 1: Figure S1. HAuCl4 susceptibility of E. coli grown under anaerobic conditions. aE. coli growth anaerobically in the presence of the indicated Au3+ concentrations. b Relationship of the area under the curve (AUC) and HAuCl4 concentration.

Additional file 2: Figure S2. Viability of E. coli exposed to Au3+ with pretreatments of ROS scavengers. Cells grown to OD600 0.4 were incubated for 30 min in the absence and presence of 2,2 bipyridyl and ascorbic acid, washed and incubated with 0.2 mM Au3+ for 15 min. The letters indicate the significance of the one-way statistical analysis ANOVA Multiple comparisons. ****p

To report the dosimetric feasibility of the radiation technique HALFMOON (Helical ALtered Fractionation for iMplant partial OmissiON) for post-mastectomy radiation therapy (PMRT) in intermediate–high-risk breast cancer patients with implant-based immediate breast reconstruction, where the clinical target volume (CTV) does not include the whole implant (implant-sparing approach). In the HALFMOON technique, the CTV consisted of skin, subcutaneous tissues, and pectoralis major muscle, excluding the implant, chest wall muscles, and rib plane. The HALFMOON plans were compared with conventionally contoured CTV plans, in which the whole implant, chest wall muscles, and ribs plane were included in the CTV, in a ratio 1:3. All patients underwent hypofractionated treatment of 40.05 Gy/15 fractions, using helical Tomotherapy®. Eighteen patients undergoing HALFMOON technique were compared to 54 subjects treated with conventionally contoured CTV plans. No difference was found in the planning target volume coverage between the two groups. Conversely, a statistically relevant dose reduction in HALFMOON patients was observed for ipsilateral lung (D15%, p

To report in-vivo dosimetry in the infraclavicular region, a potential site of a cardiac implantable electronic device (CIED) and to evaluate the absorbed dose from intraoperative radiotherapy with electrons (ELIOT). 27 non-cardiopathic breast cancer (BC) patients without CIED received quadrantectomy and ELIOT as partial breast irradiation. Before delivering ELIOT, two catheters, each containing eight thermoluminescent dosimeters (TLDs), were positioned in the infraclavicular region. TLDs internal catheter was located deep in the tumor bed while the external catheter was placed on patient’s skin. Data were available for 24/27 patients. The absorbed doses were referred to the dose of 21 Gy. Values measured by the external catheter were low, although statistically significant higher doses were found close to the applicator (mean values 0.26–0.49 Gy). External TLD doses in proximity of the applicator were lower than those detected by their internal counterparts. Values measured by the internal catheter TLDs varied according to the distance from the applicator while no correlation with tumor site and beam energy was found. The distance from the applicator to deliver

Intensity-modulated radiotherapy (IMRT) is considered the preferred option in squamous cell canal cancer (SCAC), delivering high doses to tumor volumes while minimizing dose to surrounding normal tissues. IMRT has steep dose gradients, but the technique is more demanding as deep understanding of target structures is required. To evaluate genital marginal failure in a cohort of patients with non-metastatic SCAC treated either with IMRT or 3DCRT and concurrent chemotherapy, 117 patients with SCAC were evaluated: 64 and 53 patients were treated with IMRT and 3DCRT techniques, respectively. All patients underwent clinical and radiological examination during their follow-up. Tumor response was evaluated with response evaluation criteria in solid tumors v1.1 guideline on regular basis. All patients’ data were analyzed, and patients with marginal failure were identified. Concomitant chemotherapy was administered in 97 and 77.4% of patients in the IMRT and 3DCRT groups, respectively. In the IMRT group, the median follow-up was 25 months (range 6–78). Progressive disease was registered in 15.6% of patients; infield recurrence, distant recurrence and both infield recurrence and distant recurrence were identified in 5, 4 and 1 patient, respectively. Two out of 64 patients (3.1%) had marginal failures, localized at vagina/recto-vaginal septum and left perineal region. In the 3DCRT group, the median follow-up was 71.3 months (range 6–194 months). Two out of 53 patients (3.8%) had marginal failures, localized at recto-vaginal septum and perigenital structures. The rate of marginal failures was comparable in IMRT and 3DCRT groups (χ2 test p = 0.85). In this series, the use of IMRT for the treatment of SCAC did not increase the rate of marginal failures offering improved dose conformity to the target. Dose constraints should be applied with caution—particularly in females with involvement of the vagina or the vaginal septum.

As a result of aging, the number of patients with cardiac implantable electronic device (CIED) requiring radiotherapy (RT) continues to rise. The aim of this work was to evaluate RT-related malfunctions of CIED in a cohort of patients who underwent RT in our clinic from June 2010 to December 2016. We retrospectively analyzed 93 RT treatments in 63 patients with CIEDs. Patients were treated with 3D conformal RT, intensity-modulated RT and stereotactic RT. We collected clinical characteristics of cancer, models of CIEDs, total RT dose to tumor and radiation energy. Radiation dose delivered to CIED and its dysfunctions after RT was evaluated. Subgroup analysis of 48 RT treatments (32 patients) on chest and neck plus on 13 RT treatments (12 patients) with 18 MV neutron-producing photon energy considered as high risk was performed. The number of treatments of patients with CIEDs increased from 0.3% in 2011 to 1.2% in 2016. Two patients, treated with 18 MV photon beam, with implantable cardioverter–defibrillators (ICDs) that received a maximum dose of around 2.1 Gy, experienced adverse events: a reprogramming of ICD when the patient reached a delivered dose to the tumor of 32 Gy, and an altered sensing function requiring replacement after 11 months from the end of RT. Nearly 2% of patients with CIEDs from high-risk patients subgroup had experienced a damage of the device. Close cooperation between radiation oncologists, cardiologists, medical physicists and radiation technologists is needed to achieve the best practice management in these patients.

Background: The aim of this study was to confirm our preliminary results with in vivo dosimetry in non-pregnant breast cancer patients receiving electron beam intraoperative radiotherapy (ELIOT) and to report on the first treatment in a pregnant woman. Patients and Methods: Following our previous experience, 5 non-pregnant patients receiving ELIOT to the tumor bed after breast-conserving surgery (BCS) were studied with thermoluminescent dosimeters positioned in the subdiaphragmatic region, within the uterus, and in the ovarian region. In December 2011, the first pregnant breast cancer patient underwent BCS and ELIOT (21 Gy at 90% isodose) during the 15th week of gestation. Results: The mean dose to the subdiaphragmatic external region in the 5 non-pregnant patients was 5.57 mGy, while pelvic measurements were below 1 mGy. The actual dosimetry of the pregnant patient showed a mean subdiaphragmatic dose of 4.34 mGy, a mean suprapubic dose of 1.64 mGy, and mean ovarian doses of 1.48 mGy (right-sided) and 1.44 mGy (left-sided). The expected dose to the fetus was estimated as 0.84 mGy (0.004% of the prescribed dose). Conclusion: ELIOT as an anticipated boost to the breast could be considered in pregnant women in the early second trimester, postponing whole-breast irradiation after delivery.

Aim: We report on acute toxicity, which is the secondary endpoint of a phase II clinical trial specifically addressed to assess the chronic toxicity of a hypofractionated scheme including a simultaneous integrated boost, with intensity modulated radiotherapy. Materials and methods: From 2/2012 to 12/2013 194 patients with early breast cancer entered a phase II study on hypofractionated radiotherapy including a boost dose to the tumor bed. All patients were operated on conservatively. The whole breast and the tumor bed are planned to receive a dose of 45 Gy and 50 Gy, respectively, in 20 fractions, over 4 weeks. Treatment plans are generated using the TomoDirect modality,which is available on Tomotherapy Hi-Art System (Madison,WI). Acute toxicity was evaluated according to the RTOG acute toxicity scale, up to 6 months after the treatment. Afterwards, chronic toxicity is evaluated using LENT/SOMA scale. Results: 95% of the volume of the breast and boost PTVs received 99% and 100% of the planned dose, as median values, respectively and 0.1% (median value) of the entire breast volume received 100% of the boost dose. The median maximum dose to the breast and to the boost PTVs was 113% and 103.3 %, respectively. At the end of treatment, the acute toxicity, was distributed as follows. As far as erythema was concerned, at the end of treatment, 58% of the patients experienced grade 1 erythema, which dropped to 23% one month later. Grade 2 erythema affected 37% of the cases, and after one month, it decreased to 2%.Only 1 patient (0.5%) complained of Grade 3 erythema at the end of the treatment, which rapidly disappeared afterwards. With regard to breast oedema, at the end of treatment grade 1 was observed in 16% of the cases, for whom it tended to remain stable after one month, while grade 2 oedema was noted in 4% of the cases, decreasing to 1.5% on the first month- follow-up visit. Regarding desquamation, dry desquamation ( grade 1) was observed in less than 10% of cases at the end of treatment, but it tended to increase to 17% one month later. Patchy moist desquamation (grade 2) was present in 1.9% of the patients at the end of radiotherapy, and in 1% of them, one month afterwards. Confluent desquamation (grade 3) was noted only in 1 patient (0.5%), who was receiving concomitant chemotherapy with cyclophospamide, methotrexate and fluoruracil: it was still present 1 month after the radiotherapy completion, as the patient continued to be on chemotherapy. No significantly different side effects were observed between the whole breast and the boost area. No patients experienced any lung and cardiac symptoms. Conclusion: The clinical results of this SIB hypofractionated scheme showed low acute toxicity. In spite of the high dose per fraction, with the tumor bed receiving an even higher dose /per fraction, acute toxicity was within the limit acknowledged by literature for conventional fractionation. This non-rotational treatment option allows us to deliver treatment with a traditional tangent-like dose, without spreading low doses to the adjacent structures. Chronic toxicity will be assessed after 2 years. Therefore, a longer follow-up is needed to assess the effective tolerance to the SIB schedule. Citation Format: Maria Cristina Leonardi, Anna Morra, Federica Cattani, Luigi Santoro, Samantha Dicuonzo, Raffaella Cambria, Rosa Luraschi, Alessia Bazani, Roberta Lazzari, Veronica Dell'Acqua, Roberto Orecchia. Simultaneous integrated boost incorporated into a hypofractionated regimen using tomoDirect: Acute toxicity assessment [abstract]. In: Proceedings of the Thirty-Seventh Annual CTRC-AACR San Antonio Breast Cancer Symposium: 2014 Dec 9-13; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2015;75(9 Suppl):Abstract nr P1-15-07.

OBJECTIVE: To evaluate high-precision external beam reirradiation (re-EBRT) for local relapse of prostate cancer (PCa) after radiotherapy. METHODS: This retrospective study included patients with biochemical failure and evidence of isolated local recurrence of PCa after radical/salvage EBRT or brachytherapy that received salvage stereotactic body radiation therapy (SBRT, re-EBRT). Biopsy was not mandatory if all diagnostic elements were univocal (prostate specific antigen evolution, choline-positron emission tomography or magnetic resonance imaging). Salvage SBRT (re-EBRT) was delivered with image-guided radiation therapy (RapidArc®, VERO® and CyberKnife®). RESULTS: Data of 64 patients were included, median age at salvage SBRT was 73.2 years, median pre-salvage SBRT prostate specific antigen was 3.89 ng ml(−1) . Median total dose was 30 Gy in five fractions, biologically effective dose (BED) of 150 Gy. One acute G3 genitourinary event and one late G3 genitourinary event were observed. No G ≥ 3 bowel toxicity was registered. At the median follow-up of 26.1 months, tumor progression was observed in 41 patients (64%). 18 patients (28%) experienced local relapse. 2-year local control, biochemical and clinical relapse free survival rates were 75, 40 and 53%, respectively. With BED ≥130 Gy 1-year biochemical and clinical progression-free survival rate were 85 and 90%, respectively. CONCLUSIONS: Salvage SBRT (re-EBRT) for isolated local PCa recurrence is a safe, feasible and noninvasive salvage treatment. Further investigation is warranted to define the optimal patient selection, dose and volume parameters. ADVANCES IN KNOWLEDGE: Salvage SBRT reirradiation for the locally recurrent PCa offer a satisfactory tumor control and excellent toxicity profile, if BED ≥130 Gy is administered.

To assess the dosimetric and clinical implication when applying the full bladder protocol for the treatment of the localized prostate cancer (PCA).A total of 26 consecutive patients were selected for the present study. Patients underwent two series of CT scans: the day of the simulation and after 40 Gy. Each series consisted of two consecutive scans: (1) full bladder (FB) and (2) empty bladder (EB). The contouring of clinical target volumes (CTVs) and organs at risk (OAR) were compared to evaluate organ motion. Treatment plans were compared by dose distribution and dose-volume histograms (DVH).CTV shifts were negligible in the laterolateral and superior-inferior directions (the maximum shift was 1.85 mm). Larger shifts were recorded in the anterior-posterior direction (95% CI, 0.83-4.41 mm). From the dosimetric point of view, shifts are negligible: the minimum dose to the CTV was 98.5% (median; 95%CI, 95-99%). The potential advantage for GU toxicity in applying the FB treatment protocol was measured: the ratio between full and empty bladder dose-volume points (selected from our protocol) is below 0.61, excluding the higher dose region where DVHs converge.Having a FB during radiotherapy does not affect treatment effectiveness, on the contrary it helps achieve a more favorable DVH and lower GU toxicities.

Aims and Background This study evaluates 3 different imaging modalities—ultrasound (US), stereoscopic X-ray imaging of implanted markers (Visicoils) (X-ray), and kV cone-beam computed tomography (CBCT)—to assess interfraction and intrafraction localization error during conformal radiation therapy of prostate cancer. Methods and Study Design The study population consisted of 186 consecutive prostate cancer patients treated with an image-guided radiotherapy (IGRT) hypofractionated protocol using 3 techniques: 32 with X-ray, 30 with CBCT, and 124 with US. Treatment dose of 70.2 Gy was delivered in 26 fractions with a conformal dynamic arcs technique. Interfraction prostate localization errors were determined for the 3 techniques. Moreover, interfraction and intrafraction prostate motion in terms of translations and rotations, as well as residual errors, were determined with X-ray. Results The systematic and random components of the prostate localization errors were as follows: ( 1 ) with X-ray 3.0 ± 3.4, 2.3 ± 2.7, 1.8 ± 2.3 mm in anterior-posterior (AP), superior-inferior (SI), and left-right (LR) directions and 1.8° ± 1.2°, 2.3° ± 1.5°, 2.7° ± 3.1°, for the yaw, roll, and pitch rotations; ( 2 ) with CBCT3.5 ± 4.2, 3.3 ± 3.3, 2.5 ± 3.1 mm in AP, SI, and LR directions; ( 3 ) with US 3.7 ± 4.7, 3.4 ± 4.3, 2.3 ± 3.5 mm in AP, SI, and LR directions. Residual errors with X-ray were less than 1 mm in all directions. Intrafraction prostate motion of less than 0.5 mm in LR and of the order of 1 mm in AP and SI directions was found. This led to a significant reduction of the margins, potentially important for dose escalation studies. Conclusions Daily on-line IGRT with stereoscopic X-ray imaging allowed a consistent PTV margin reduction considering residual interfraction prostate localization error and intrafraction motion. X-ray offers the best compromise among accuracy, reliability, dose to the patient, and time investment for daily IGRT treatment of prostate.

To quantify the advantages of a 6 degrees of freedom (dof) versus the conventional 3- or 4-dof correction modality for stereotactic body radiation therapy (SBRT) treatments. Eighty-five patients were fitted with 5-7 infra-red passive markers for optical localization. Data, acquired during the treatment, were analyzed retrospectively to simulate and evaluate the best approach for correcting patient misalignments. After the implementation of each correction, the new position of the target (tumor's center of mass) was estimated by means of a dedicated stereotactic algorithm. The Euclidean distance between the corrected and the planned location of target point was calculated and compared to the initial mismatching. Initial and after correction median+/-quartile displacements affecting external control points were 3.74+/-2.55 mm (initial), 2.45+/-0.91 mm (3-dof), 2.37+/-0.95 mm (4-dof), and 2.03+/-1.47 mm (6-dof). The benefit of a six-parameter adjustment was particularly evident when evaluating the results relative to the target position before and after the re-alignment. In this context, the Euclidean distance between the planned and the current target point turned to 0.82+/-1.12 mm (median+/-quartile values) after the roto-translation versus the initial displacement of 2.98+/-2.32 mm. No statistical improvements were found after 3- and 4-dof correction (2.73+/-1.22 mm and 2.60+/-1.31 mm, respectively). Angular errors were 0.09+/-0.93 degrees (mean+/-std). Pitch rotation in abdomen site showed the most relevant deviation, being -0.46+/-1.27 degrees with a peak value of 5.46 degrees . Translational misalignments were -0.68+/-2.60 mm (mean+/-std) with the maximum value of 12 mm along the cranio-caudal direction. We conclude that positioning system platforms featuring 6-dof are preferred for high precision radiation therapy. Data are in line with previous results relative to other sites and represent a relevant record in the framework of SBRT.

This study investigated the risk of reconstruction failure after mastectomy, immediate breast reconstruction, and radiotherapy to either a temporary tissue expander or permanent implant.Records of women treated at a single institution between June of 1997 and December of 2011 were reviewed. Two patient groups were identified based on type of immediate breast reconstruction: tissue expander followed by exchange with a permanent implant and permanent implant. The study endpoint was rate of reconstruction failure, defined as a replacement, loss of the implant, or conversion to flap.The tissue expander/permanent implant and the permanent implant groups consisted of 63 and 75 patients, respectively. The groups were well balanced for clinical and treatment characteristics. With a median follow-up of 116 months, eight implant losses, 50 implant replacements, and four flap conversions were recorded. Reconstruction failure occurred in 22 of 63 patients in the expander/implant group and in 40 of 75 patients in the permanent implant group. A traditional proportional hazards model showed a higher risk of reconstruction failure for the expander/implant group (hazard ratio, 2.01) and a significantly shorter time to reconstruction failure compared with the permanent implant group (109.2 months versus 157.7 months; p = 0.03); however, according to a competing risk model, the between-groups cumulative incidences were not significantly different (hazard ratio, 1.09).Radiotherapy to either a tissue expander or a permanent implant presented a fairly large risk of reconstruction failure over time. The expander/implant group was not more likely to develop reconstruction failure compared to permanent implant group, but the timing of onset was shorter. More complex techniques should be investigated to lower the risk of reconstruction failure.Therapeutic, III.