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Although global heart dose has been associated with late cardiac toxic effects in patients who received radiation therapy for breast cancer, data detailing the clinical significance of cardiac substructure dosimetry are limited. We investigated whether dose to the left anterior descending artery (LAD) correlates with adverse cardiac events.We identified 375 consecutively treated female patients from 2012 to 2018 who received left-sided breast or chest wall irradiation (with or without regional nodal irradiation). Medical records were queried to identify cardiac events after radiation therapy. Mean and maximum LAD and heart doses (LAD DMedian follow-up time was 48 months. Thirty-six patients experienced a cardiac event, and 23 patients experienced a major cardiac event. On univariate and multivariable analyses, increased LAD DDose to the LAD correlated with adverse cardiac events in this cohort. Contouring and minimizing dose to the LAD should be considered for patients receiving radiation therapy for left-sided breast cancer.

Dose to the left anterior descending artery (LAD) may be significant in patients receiving left-sided irradiation for breast cancer. We investigated if prospective contouring and avoidance of the LAD during treatment planning were associated with lower LAD dose.We reviewed dosimetric plans for 323 patients who received left whole breast or chest wall irradiation with or without internal mammary node (IMLN) coverage between 1/2014 and 1/2019 at a single institution. The LAD was contoured prospectively for 155 cases, and techniques were utilized to minimize LAD dose. Dose-volume-histograms from these patients were compared to those of 168 patients for whom the LAD was contoured retrospectively after treatment completion. EQD2 was calculated to account for fractionation differences.Compared to cases where the LAD was contoured retrospectively (n = 126), prospective LAD contouring (n = 124) was associated with lower unadjusted median max and mean LAD doses for 250 patients receiving whole-breast irradiation (WBI) without IMLN coverage: 8.5 Gy vs 5.2 Gy (p0.0001) and 3.6 Gy vs 2.7 Gy (p0.0001), respectively. EQD2 median max and mean LAD doses were also lower with prospective LAD contouring: 5.2 Gy vs 3.0 Gy (p0.0001) and 1.9 Gy vs 1.5 Gy (p0.0001), respectively. Compared to cases where the LAD was contoured retrospectively (n = 42), prospective LAD contouring (n = 31) was associated with lower max LAD doses for 73 patients with IMLN coverage: 20.4 Gy vs 14.3 Gy (p = 0.042). There was a nonsignificant reduction in median mean LAD dose: 6.2 Gy vs 6.1 Gy (p = 0.33). LAD doses were reduced while maintaining IMLN coverage (mean V90%Prospective contouring and avoidance of the LAD were associated with lower max and mean LAD doses in patients receiving WBI and with lower max LAD doses in patients receiving IMLN treatment. Further reduction in LAD dose may require stricter optimization weighting or compromise in IMLN coverage.

Purpose/objective(s) Merkel cell carcinoma (MCC) is a rare, aggressive cutaneous neoplasm traditionally managed with surgical resection followed by radiotherapy (RT). With the recent approval of checkpoint inhibitors, chemotherapy is less commonly utilized. We analyzed the impact of RT and chemotherapy on overall survival (OS) in patients with MCC using Surveillance, Epidemiology, and End Results (SEER), a population-level database. Materials and methods We performed retrospective analyses on SEER 18 Custom Data registries for MCC (ICD-0-3 8247). Data from 1980 to 2016 was queried for analysis, and an initial list of 9,792 patients was populated (ICD: C00, C07.9, C44, C80.9). Selection for cases with chemotherapy and RT status, single primary tumor, primary tumor location and surgery treatment type yielded 5,002 cases for analysis. Baseline characteristics were compared with Chi-square or Mann-Whitney U test. Univariate and multivariable analysis using Kaplan-Meier and Cox proportional hazards regression modeling were performed. Propensity-score matched analysis with inverse probability of treatment weighting (IPTW) was used to account for indication bias. Results Median follow-up time was 178 months (68 to 217 months). Independent prognostic factors positively correlated with increased OS, for both unadjusted Multivariate analysis and IPTW adjusted MVA were age, male sex, year of diagnosis, stage, RT status, and chemotherapy status. On adjusted MVA, use of chemotherapy was associated with worse OS (hazard ratio: 1.22 [95% CI 1.1-1.35], p

Background The optimal management of patients with stage I-II squamous cell carcinoma (SCC) of the anus is controversial. The current study evaluates the efficacy of combined chemotherapy and radiation therapy (CRT) versus radiation therapy (RT) alone in the treatment of these patients using the Surveillance, Epidemiology, and End Results (SEER) registries. Methods SEER 18 Custom Data registries were queried for patients with stage I-II SCC of the anus. Univariate analysis (UVA) and multivariable analysis (MVA) using Kaplan-Meier and Cox proportional hazards regression modeling were performed. Propensity-score matched analysis with inverse probability of treatment weighting (IPTW) was used to account for indication bias. Results A total of 4,288 patients with stage I-II disease were identified, of whom 3,982 (93%) underwent CRT and 306 (7%) underwent RT. Median follow-up was 42 months. Approximately 30.8% had T1 disease and 69.2% had T2-T3 disease. The IPTW-adjusted 5-year overall survival (OS) was 76.7%, with no significant differences between the CRT and RT groups (77% vs. 73.5%, P=0.33). On multivariate IPTW-adjusted analysis, the lack of association between CRT use and OS was upheld (HR, 0.84, 95% CI, 0.65-1.08, P=0.2). On subgroup analyses, 5-year OS was 86% with CRT (n=1,216) and 84.2% with RT (n=103) (P=0.74) in stage I (T1N0) patients, while 5-year OS was 72.8% with CRT (n=2,766) and 66.4% with RT (n=203) (P=0.13) in stage II (T2-3N0) patients. CRT was associated with improved median OS in stage II patients (119 months vs. not reached, P=0.04). Conclusions The current study suggests that omission of concurrent chemotherapy is not associated with inferior OS in patients with stage I SCC of the anus. However, combined chemoradiation was superior to radiation alone in patients with stage II disease. Prospective evidence is needed to optimize clinical decision-making in this patient population.