A Phase 2 Study of 2 Weeks of Adjuvant Whole Breast/Chest Wall and/or Regional Nodal Radiation Therapy for Patients With Breast Cancer.

PURPOSE: To report the results in terms of feasibility and early toxicity of hypofractionated adjuvant whole breast/chest wall and/or regional nodal radiation therapy for patients with breast cancer.

METHODS AND MATERIALS: From June 2013 to October 2014, 50 patients with breast cancer after mastectomy or after breast conservation surgery (BCS) were prospectively included. The institutional ethics committee approved the study, which was registered with ClinicalTrials.gov (ClinicalTrials.gov identifier no. NCT02460744). Treatment planning was performed using a simulator with 2 tangential fields to the breast/chest wall and an incident field to the supraclavicular fossa. The radiation dose delivered was 34 Gy in 10 fractions within 2 weeks, followed by a boost of 10 Gy in 5 fractions within 1 week for patients who underwent BCS. Acute skin toxicities were recorded during and after treatment according to the Radiation Therapy Oncology Group acute radiation toxicity scoring criteria. The primary objective was to obtain estimates of the acute toxicity rates and cosmetic outcomes that could be used to design a subsequent phase III comparative study. Acute skin and late toxicities were recorded during and after treatment. Cosmetic outcomes were assessed before and after treatment and during the regular follow-up period. A cost/benefit analysis was also performed and compared with that for standard treatment of 35 Gy in 15 fractions within 3 weeks.

RESULTS: The median follow-up was 39 months (range 14-48). The mean age was 51 years (range 26-75). A left-sided tumor was present in 25 patients (50%). Total mastectomy with axillary clearance was performed in 40 (80%) and BCS in 10 (20%) patients. Acute grade 2 and 3 skin toxicity was seen in 16 (32%) and 1 (2%) patient, respectively. In the BCS patients, grade 2 skin and subcutaneous toxicity was seen in 2 (20%) and 1 (10%) patient, respectively. Grade 2 edema was seen in 1 patient (10%). The cosmesis was excellent or good in 8 (80%) and fair or poor in 2 (20%) patients. The cost/benefit analysis revealed significantly less financial burden on the patients with 2 weeks of treatment. Disease-free and overall survival at 3 years was 94% and 96%, respectively.

CONCLUSIONS: Hypofractionated radiation therapy within 2 weeks appears to be feasible for patients with breast cancer and was associated with acute and late skin toxicity profiles similar to those observed with 3 weeks of treatment. The financial burden on the patient and family could be reduced with 2 weeks of treatment. Long-term follow-up data and a prospective comparative study are needed to strengthen these results. Hypofractionation might help radiation centers worldwide to meet the increasing need for radiation for breast cancer, especially in developing countries where resources are limited and patients must travel long distances for treatment.