Hypofractionated radiotherapy for breast cancer: how to evaluate chronic toxicity and cosmesis?

Adjuvant irradiation constitutes an important component in the postoperative treatment of breast cancer, reaching as far as 25–30% of workload in radiotherapy departments. Some approaches to reduce delays and optimize available resources include accelerated schedules of daily doses slightly superior to standard ones (1). Several trials had utilized altered fractionations ranging from 2.5 Gy in 16 fractions to 3.3 Gy in 13 fractions (2,3), showing almost an equivalent safety and effectiveness compared to standard fractionation. These results have been confirmed in large randomized trials. In the Ontario Clinical Oncology Group published by Whelan et al. (4), 1,234 patients with T1-2N0 tumors were randomized to receive 42.5 Gy in 16 fractions compared with the standard 50 Gy in 25 fractions. After a follow-up of 10 years the local control was 93.8% and 93.3% in both groups respectively and the chronic toxicity and cosmesis was similar in both arms. In UK START A (5) and B (6) trials similar results were obtained confirming the same safety and efficacy of the hypofractionation schedule compared to the standard one, and also with a slightly less chronic toxicity and better cosmesis in the hypofractionated arms. According to these good results, daily hypofractionation is actually the preferred choice after conservative surgery in breast cancer, has been included in recommendations and clinical guidelines (7), and is considered the standard of care (8). In conclusion, moderate hypofractionation is a safe treatment modality without compromising effectiveness and has direct implications in health care systems (9)