Hypofractionated radiotherapy for breast cancer including risk-adapted boost: Update on tolerance and efficacy of an accelerated START a regime

Aim: To present an update of a prospective study evaluating an accelerated hypofractionated whole breast irradiation (WBI) schedule of the START A trial plus hypofractionated boost in breast cancer patients. Patients and Methods: One hundred and forty consecutive patients ≥55 years were included in this study. Patients received postoperative WBI with 13×3.2 Gy to 41.6 Gy plus a boost of 3.0 Gy/fraction to 9-12 Gy applied in <3.5 weeks, depending on the resection margin. Prospectively planned follow-up (FU) visits, including objective and subjective assessment of treatment tolerance, were performed at 0 and 8 weeks, as well as one, two, four or more years following radiotherapy (RT). Results: The 3-year rates of local control, nodal control, disease-free and overall survival were 99%, 100%, 96% and 91%, respectively. Cosmetic outcome was very good with 99% (n=110/111), 98% (n=99/101) and 100% (n=59/59) of the patients being satisfied or very satisfied one, two and four years after RT, respectively. Conclusion: Acceleration of the START A regime with 41.6 Gy WBI plus additional boost of 9-12 Gy remained effective and well-tolerated.