HYPofractionated Adjuvant RadioTherapy in 1 Versus 2 Weeks in High-Risk Patients With Breast Cancer (HYPART): Acute Toxicity Results.

Abstract

The HYPofractionated Adjuvant RadioTherapy study aimed to compare a 1-week adjuvant radiation therapy (RT) schedule with a 2-week schedule in high-risk patients with breast cancer. Here we present the acute toxicity data of the study. The HYPofractionated Adjuvant RadioTherapy study was approved by the institutional ethics committee and was registered with ClinicalTrials.gov ID NCT04472845 and CTRI with REF/2020/09/037050. Patients with high-risk breast cancer after mastectomy or breast conserving surgery were randomized to receive an RT dose of 26 Gy in 5 fractions over 1 week or 34 Gy in 10 fractions over 2 weeks. Patients who underwent breast conserving surgery received a sequential or simultaneous integrated boost with a dose of 8 Gy/2#/2 days. Patients were planned and treated with a 2-dimensional or 3-dimensional technique. Acute radiation toxicities were assessed according to the Radiation Therapy Oncology Group grading system. A total of 941 patients treated between October 2020 and June 2024 were included in this analysis. Acute toxicity grade 0, 1, 2, and 3 with 1 week and 2 week schedules were observed in 265 (55%) versus 248 (54%), 141 (29.3%) versus 155 (33.8%), 73 (15.1%) versus 54 (11.8%), and 3 (0.6%) versus 2 (0.4%) patients (P = .282), respectively. Dysphagia was reported as grade 0, 1, and 2 in 461 (95.6%) versus 413 (90%), 14 (2.9%) versus 41 (8.9%), and 7 (1.5%) versus 5 (1.1%) patients with a 1-week and 2-week schedule (P = .001), respectively. Grade 1 and 2 arm pain was observed in 8 (1.6%) versus 8 (1.7%) and 7 (1.5%) versus 4 (0.9%) patients with a 1-week and 2-week schedule (P = .753), respectively. Acute arm edema was grade 1 and 2 in 100 (20.8%) versus 81 (17.6%), and 20 (4.1%) versus 28 (6.1%) patients in the 1-week and 2-week schedule (P = .227), respectively. Grade 1 and 2 cough was reported in 5 (1.0%) versus 2 (0.4%) and 4 (0.8%) versus 3 (0.7%) patients in the 1-week and 2-week schedule (P = .700), respectively. Dysphagia was less with the 1-week RT schedule as compared to the 2-week schedule. The trial showed the safety and tolerability of a 1-week regional nodal irradiation course and provided toxicity rates that will help future studies in sample size calculations.