Benefits of adjuvant hypofractionated radiotherapy (HFRT) over 3 weeks were similar to those of adjuvant conventional fractionated radiotherapy (CFRT) over 5 weeks in patients with high-risk breast cancer, according data presented at the 59th Annual Meeting of the American Society for Radiation Oncology (ASTRO).
Evidence from prior studies have suggested that HFRT may have similar results as CFRT in women with early stage breast after breast conservation surgery.
For this study, researchers randomly assigned 811 patients with stage II to III breast cancer after mastectomy to receive HFRT (43.5 Gy delivered in 15 fractions over 3 weeks) or CFRT (50 Gy delivered in 25 fractions over 5 weeks). All patients received chemotherapy and approximately 94% of patients received hormonal therapy. Baseline characteristics were well balanced between the treatment arms. The primary outcome was locoregional recurrence (LRR).
At the median follow-up of 52 months, the 5-year cumulative incidence of LRR was 92.8%. The 5-year rates of overall survival (OS), disease-free survival (DFS), and distant metastases (DM) were 86%, 74.9%, and 22.7%, respectively.
No significant differences were observed between the HFRT and CFRT groups, respectively, in 5-year LRR (8.4% vs 6.0%; P =.396), OS (84.9% vs 87.1%; P =.562), DFS (75.1% vs 74.6%; P =.841), and DM (21.3% vs 24.3%; P =.530).
Both treatments had similar rates of symptomatic radiation pneumonitis, shoulder disorder, and lymphedema. Patients in the HFRT arm experienced fewer instances of grade 3 acute skin toxicity (3.5%) compared with patients receiving CFRT (7.8%; P =.008).
The results of the study demonstrated that HFRT and CFRT may have similar outcomes and toxicity profiles in patients with high-breast cancer, and the authors noted that long-term follow up is needed.
1. Sun GY, Wang SL, Song YW, et al. Hypofractionated radiation therapy after mastectomy for the treatment of high-risk breast cancer: 5-year follow-up result of a randomized trial. Oral presentation at: 59th Annual Meeting of the American Society for Radiation Oncology; September 24-27, 2017; San Diego, CA. Abstract 5.