Fifteen-year results of a randomized prospective trial of hyperfractionated chest wall irradiation versus once-daily chest wall irradiation after chemotherapy and mastectomy for patients with locally advanced noninflammatory breast cancer

Abstract

To analyze the results of a Phase III clinical trial that investigated whether a hyperfractionated radiotherapy (RT) schedule could reduce the risk of locoregional recurrence in patients with locally advanced breast cancer treated with chemotherapy and mastectomy. Between 1985 and 1989, 200 patients with clinical Stage III noninflammatory breast cancer were enrolled in a prospective study investigating neoadjuvant and adjuvant chemotherapy. Of the 179 patients treated with mastectomy after neoadjuvant chemotherapy, 108 participated in a randomized component of the trial that compared a dose-escalated, hyperfractionated (twice-daily, b.i.d.) chest wall RT schedule (72 Gy in 1.2-Gy b.i.d. fractions) with a once-daily (q.d.) schedule (60 Gy in 2-Gy q.d. fractions). In both arms of the study, the supraclavicular fossa and axillary apex were treated once daily to 50 Gy. The median follow-up period was 15 years. The 15-year actuarial locoregional recurrence rate was 7% for the q.d. arm and 12% for the b.i.d. arm (p=0.36). The rates of severe acute toxicity were similar (4% for q.d. vs. 5% for b.i.d.), but moist desquamation developed in 42% of patients in the b.i.d. arm compared with 28% of the patients in the q.d. arm (p=0.16). The 15-year actuarial rate of severe late RT complications did not differ between the two arms (6% for q.d. vs. 11% for b.i.d., p=0.54). Although the sample size of this study was small, we found no evidence that this hyperfractionation schedule of postmastectomy RT offered a clinical advantage. Therefore, we have concluded that it should not be further studied in this cohort of patients.