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Background: High-level evidence is lacking to guide treatment decisions about postmastectomy radiation therapy (PMRT) in patients who have breast cancer with 1 to 3 positive lymph nodes who receive contemporary systemic therapies, leading to potential variations in PMRT delivery. The objective of this study was to examine nationwide trends in PMRT use in this group., Methods: The National Cancer Data Base (NCDB) was used to identify 93,372 women who had T1-T2N1 breast cancer diagnosed between 2003 and 2012. Patients who received neoadjuvant chemotherapy or radiation therapy (RT) and those who had bilateral breast cancers were excluded. Time trends were evaluated using the Cochrane-Armitage test and correlated the receipt of PMRT with various patient demographic, facility, clinicopathologic, and treatment variables using multivariable logistic regression. A second analysis was performed for patients who were diagnosed during 2010 and included radiation oncologist density as an additional covariate. P values < .0001 were considered statistically significant., Results: Overall, 22.5% of the study population received PMRT, representing an increase from 19.1% in 2003 to 30.3% in 2012. Factors associated with greater PMRT use included younger age, lower Charlson-Deyo comorbidity scores, shorter distance to the treating facility, treatment at a comprehensive cancer program, facility location in the New England Census division, and higher density of radiation oncologists. Increased PMRT use was associated with later year of diagnosis, receipt of chemotherapy, receipt of hormone therapy, higher grade disease, larger tumor size, greater numbers of positive lymph nodes, positive margins, and absence of immediate breast reconstruction (all P < .0001)., Conclusions: The receipt of PMRT by patients with breast cancer who have 1 to 3 positive lymph nodes has increased over time, with wide variability in practice patterns in the United States. Cancer 2018;124:482-90. © 2017 American Cancer Society., (© 2017 American Cancer Society.)

To determine if the presence of bilateral implants, in addition to other anatomic and treatment-related variables, affects coverage of the target volume and dose to the heart and lung in patients receiving postmastectomy radiation therapy (PMRT). A total of 197 consecutive women with breast cancer underwent mastectomy and immediate tissue expander (TE) placement, with or without exchange for a permanent implant (PI) before radiation therapy at our center. PMRT was delivered with 2 tangential beams + supraclavicular lymph node field (50Gy). Patients were grouped by implant number: 51% unilateral (100) and 49% bilateral (97). The planning target volume (PTV) (defined as implant + chest wall + nodes), heart, and ipsilateral lung were contoured and the following parameters were abstracted from dose-volume histogram (DVH) data: PTV D95% > 98%, Lung V20Gy > 30%, and Heart V25Gy > 5%. Univariate (UVA) and multivariate analyses (MVA) were performed to determine the association of variables with these parameters. The 2 groups were well balanced for implant type and volume, internal mammary node (IMN) treatment, and laterality. In the entire cohort, 90% had PTV D95% > 98%, indicating excellent coverage of the chest wall. Of the patients, 27% had high lung doses (V20Gy > 30%) and 16% had high heart doses (V25Gy > 5%). No significant factors were associated with suboptimal PTV coverage. On MVA, IMN treatment was found to be highly associated with high lung and heart doses (both p < 0.0001), but implant number was not (p = 0.54). In patients with bilateral implants, IMN treatment was the only predictor of dose to the contralateral implant (p = 0.001). In conclusion, bilateral implants do not compromise coverage of the target volume or increase lung and heart dose in patients receiving PMRT. The most important predictor of high lung and heart doses in patients with implant-based reconstruction, whether unilateral or bilateral, is treatment of the IMNs. Refinement of radiation techniques in reconstructed patients who require comprehensive nodal irradiation is warranted., (Copyright © 2014 American Association of Medical Dosimetrists. Published by Elsevier Inc. All rights reserved.)

Background: Postmastectomy radiation therapy (PMRT) decreases the risk of locoregional recurrence and increases overall survival rates in patients with high-risk node positive breast cancer. While the number of breast cancer patients treated with proton-based PMRT has increased in recent years, there is limited data on the use of proton therapy in the postmastectomy with reconstruction setting. In this study, we compared acute toxicities and reconstructive complications in patients treated with proton-based and photonbased PMRT. Methods: A retrospective review of our institutional database was performed to identify breast cancer patients treated with mastectomy with implant or autologous reconstruction followed by PMRT from 2015 to 2020. Baseline clinical, disease, and treatment related factors were compared between the photon-based and proton-based PMRT groups. Early toxicity outcomes and reconstructive complications following PMRT were graded by the treating physician. Results: A total of 11 patients treated with proton-based PMRT and 26 patients treated with photon-based PMRT were included with a median follow-up of 7.4 months (range, 0.7-33 months). Six patients (55%) in the proton group had a history of breast cancer (3 ipsilateral and 3 contralateral) and received previous RT 38 months ago (median, range 7-85). There was no significant difference in mean PMRT (p = 0.064) and boost dose (p = 0.608) between the two groups. Grade 2 skin toxicity was the most common acute toxicity in both groups (55% and 73% in the proton and photon group, respectively) (p = 0.077). Three patients (27%) in the proton group developed grade 3 skin toxicity. No Grade 4 acute toxicity was reported in either group. Reconstructive complications occurred in 4 patients (36%) in the proton group and 8 patients (31%) in photon group (p = 0.946). Conclusions: Acute skin toxicity remains the most frequent adverse event in both proton- and photon-based PMRT. In our study, reconstructive complications were not significantly higher in patients treated with proton-versus photon-based PMRT. Longer follow-up is warranted to assess late toxicities. [ABSTRACT FROM AUTHOR]

Adjuvant radiation therapy is often delivered after breast cancer surgery, both in the post‐lumpectomy and post‐mastectomy settings. Standard fractionation whole breast irradiation (SF‐WBI), which is typically delivered over 5‐7 weeks, was previously considered the standard of care. More recent data has helped to establish hypofractionated whole breast irradiation (HF‐WBI), which consists of a 3‐4 week regimen, as a new standard of care. This article provides an overview of the major randomized trials that support the routine use of HF‐WBI for the majority of patients undergoing breast‐conserving surgery for early‐stage breast cancer. Newer data on the use of a hypofractionated approach in the post‐mastectomy setting, as well as ongoing randomized trials addressing this topic, are also discussed. [ABSTRACT FROM AUTHOR]

Purpose: To analyze postmastectomy radiation therapy (PMRT) usage and its association with overall survival (OS) in breast cancer patients with pathologically positive lymph nodes after neoadjuvant chemotherapy (NAC).Methods and Materials: Using the National Cancer Database, we identified women with nonmetastatic breast cancer diagnosed from 2004 to 2013 who had received NAC and undergone mastectomy with macroscopic pathologically positive lymph nodes. Joinpoint regression models were used to assess temporal trends in annual PMRT usage. Multivariable regression models were used to identify factors associated with PMRT use. A time-dependent Cox model was used to evaluate the predictors of mortality.Results: The study included 29,270 patients, of whom 62.5% received PMRT. PMRT was markedly underused among all nodal subgroups, in particular, among ypN2 (68.4%) and ypN3 (67.0%) patients. Hispanic patients and those with Medicaid or Medicare insurance were less likely to receive PMRT than were non-Hispanics and patients with other insurance carriers. The adjusted 5-year OS rates were similar in ypN1 and ypN2 patients with or without PMRT but were significantly greater in ypN3 patients receiving PMRT (66% vs 63%; P=.042). On multivariable analysis, PMRT was associated with improved survival only among ypN3 patients after adjusting for patient, facility, and tumor variables (multivariable hazard ratio 0.85; 95% confidence interval 0.74-0.97).Conclusions: A considerable portion of breast cancer patients with advanced residual nodal disease after NAC did not receive appropriate adjuvant radiation. We also found socioeconomic disparities in national PMRT practice patterns. Patients with ypN3 disease might derive a survival benefit from PMRT. [ABSTRACT FROM AUTHOR]