Sep 28

SS 07 - Breast Cancer 1: Redefining Radiation Schedules: Hypofractionation and APBI Across the Breast Cancer Spectrum

142 - Moderate Hypofractionated Radiotherapy for Regional Nodal Irradiation and Postmastectomy Radiation Therapy: A Systematic Review and Meta-Analysis

05:05pm - 05:15pm PT

Room 301-304

Presenter(s)

Juliane Hoerner-Rieber, MD - University Hospital Duesseldorf, Department of Radiation Oncology, Düsseldorf, Nordrhein-

J. Haussmann¹, L. M. Irschfeld², T. Sander², W. Budach¹, E. Boelke¹, C. Matuschek¹, J. Neuwahl², D. Jazmati³, and J. Hoerner-Rieber⁴; ¹Department of Radiation Oncoloy, Heinrich Heine University, Dusseldorf, Germany, ²Heinrich Heine University, Dusseldorf, Germany, ³Medical Faculty Heinrich Heine University, Dusseldorf, Germany, ⁴University of Dusseldorf, Dusseldorf, Germany

Purpose/Objective(s): Moderate hypofractionated radiotherapy (HFx) has become the standard of care following breast-conserving surgery for breast cancer. However, its extension to chest wall irradiation with or without reconstruction, as well as its inclusion for regional nodal irradiation (RNI), remains controversial. The tolerability and oncological effectiveness of HFx in these settings have not yet been conclusively determined.

Materials/Methods: A systematic literature review was conducted to identify randomized trials comparing moderate hypofractionated radiotherapy (HFx, 13-16 fractions) with conventionally fractionated radiotherapy (ConFx, 23-25 fractions) in patients receiving either RNI or postmastectomy radiation therapy (PMRT). Studies solely investigating whole-breast irradiation after breast-conserving surgery were excluded. Evaluated endpoints included locoregional control (LRC), distant metastasis (DM), disease-free survival (DFS), breast cancer-specific survival (BCSS), and overall survival (OS). Reported toxicity rates were analyzed by extracting event rates from published studies, using odds ratios (ORs). Studies were analyzed collectively as well as separately for RNI and PMRT.

Results: A total of 27 randomized trials, encompassing 7,491 patients, were identified, with a median follow-up of five years. There was no significant difference in LRC between HFx and ConFx (OR=0.88, 95% CI: 0.70-1.11, p=0.295). Similarly, no significant differences were observed in DM, DFS, BCSS, or OS. HFx was associated with significantly fewer acute skin toxicities (OR=0.41, 95% CI: 0.18-0.92, p=0.030). There was no difference in the rates of chronic lymphedema (OR=1.00, 95% CI: 0.87-1.16, p=0.961), arm mobility impairment (OR=0.97, 95% CI: 0.58-1.62, p=0.909), intramammary fibrosis, or complications after breast reconstruction.

Conclusion: Moderate hypofractionated radiotherapy for regional nodal irradiation and chest wall irradiation yields equivalent oncological outcomes and similar toxicity rates compared to conventional fractionation. Given its favorable toxicity profile and convenience, it should be considered a standard treatment option for breast cancer radiotherapy.