Hypofractionated Radiation Therapy (HFRT) of Breast/Chest Wall and Regional Nodes in Locally Advanced Breast Cancer: Toxicity Profile and Survival Outcomes in Retrospective Monoistitutional Study.

Aim: To evaluate the efficacy and safety of hypofractionated radiation therapy (HFRT) of the breast/chest wall and regional nodes in patients with locally advanced breast cancer and positive lymph nodes.

Materials And Methods: One hundred and twenty-two patients treated between October 2016 and March 2020 with HFRT were retrospectively reviewed. A total dose of 42.4 Gy was delivered to the chest wall and lymph nodes in 16 fractions of 2.65 Gy each, using the IMRT technique. Patients treated with breast-conserving surgery received an overdose (concomitant boost of 3 Gy daily) with the SIB (Simultaneous Integrated Boost) technique.

Results: Median age at diagnosis was 58 years (range 34-86 years) and median follow-up was 22 months (range 6-48 months). Overall survival (OS) at 1, 2 and 3 years was 100%, 97.3% and 90%, respectively. Disease-free survival (DFS) at 1, 2, and 3 years was 91.4%, 87%, and 84.8%, respectively. Distant metastasis-free survival (MFS) at 1, 2 and 3 years was 93.1%, 88% and 85.7%, respectively. Two patients (1.6%) experienced local recurrence on the chest wall during FUP. Twenty-one patients (17%) showed a grade 2 dermal toxicity, no grade 3 acute skin toxicity was found. Sixteen patients (13%) showed early-stage arm lymphedema (grade ≤ 2). Twenty-three patients (19%) showed a grade 2 late skin toxicity. Twenty patients (16%) had grade ≤ 2 late arm lymphedema.

Conclusion: Given the excellent local control, survival rates and the low toxicity profile demonstrated, HFRT could be considered a valid therapeutic option in patients with locally advanced breast cancer.