Abstract P4-12-12: Outcomes of exclusive radiation therapy for breast cancer in older women according to age and comorbidity status: An observational retrospective study

Introduction: This study aimed to assess the efficacy, tolerance and impact of comorbidities on outcomes in older women treated by exclusive radiation therapy (RT) for non-metastatic breast cancer (BC). Material and methods: We studied retrospectively female patients older 70 years at diagnosis, treated by exclusive RT for their BC between 2003 and 2013 in our Department. We analysed overall survival (OS), progression free survival (PFS), and specific survival (SS). Comorbidities were evaluated with the Charlson Comorbidity Index (CCI), and toxicities with the CCTCAE v3.0. Results: Between 2003 and 2013, there were 978 patients older than 70 treated for BC in our Hospital, and 817 received RT. Hypofractionated RT was delivered in 90.2% of patients. Of them, 66 patients underwent exclusive RT after refusal of surgery. The median age was 84.8 [71.3-91.7]. The median follow-up was 51.9 months [0.5- 99]. OS, SS and PFS at 5 years were 65.5% CI 95% [54.1-79.3], 86.3% CI 95% [77.2-96.4]), and 58.4% CI 95% [46.9-72.7], respectively. Five-year OS was statistically different according to age younger or older than 85 years: 72.9% CI 95% [58.4-91.1] and 57.1%, IC 95% [40.8-79.8], (p = 0.0026). Similar results were found for 5-year PFS: 64.5% CI 95% [49.5-84.1] and 51.6% CI 95% [35.8-74.5] (p = 0.014). The 5-year OS was also statistically different according to CCI score, respectively 70.8% CI 95% [57.0-87.9] and 59.8% CI 95 % [42.4-84.3] (p = 0.039) for a score of 0 or ≥ 1. Median CCI score was 1. There were 10.6% of the patients who experienced no toxicities; there were 59% who presented grade 1 and 2 radiodermatitis. Late toxicities were mainly fibrosis, observed in 39.4% of the patients, mostly of grade 1 and 2.Conclusion: Exclusive radiation therapy for non-metastatic BC in older women is feasible and well tolerated when adapted techniques are used, but the prognostic is strongly impacted by age and comorbidities. Citation Format: Lorraine Waechter, Kim Cao, Matthieu Carton, Youlia Kirova, Alain Fourquet. Outcomes of exclusive radiation therapy for breast cancer in older women according to age and comorbidity status: An observational retrospective study [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P4-12-12.