As reported in the The New England Journal of Medicine by Kunkler et al, the phase III SUPREMO trial showed no significant difference in 10-year overall survival in women with breast cancer receiving vs not receiving postmastectomy chest-wall irradiation.
Study Details
In the international trial (approximately three-quarters of patients from the United Kingdom), 1,607 patients treated with mastectomy, an axillary procedure, and systemic therapy were randomly assigned to receive chest wall irradiation at 40 Gy in 15 fractions to 50 Gy in 25 fractions (n = 808) or no chest wall irradiation (n = 799). The primary endpoint was overall survival, with 10 years of follow-up in the intention-to-treat population.
Key Findings
Median follow-up was 9.6 years. Kaplan-Meier estimates of 10-year overall survival were 81.4% in the irradiation group vs 81.9% in the no-irradiation group (hazard ratio [HR] = 1.04, 95% confidence interval [CI] = 0.82–1.30, P = .80).
Chest wall recurrence was observed in 9 patients (1.1%) in the irradiation group vs 20 (2.5%) in the no-irradiation group (between-group difference = < 2 percentage points, HR = 0.45, 95% CI = 0.20–0.99). Disease-free survival estimates at 10 years were 76.2% in the irradiation group vs 75.5% in the no-irradiation group (HR = 0.97, 95% CI = 0.79–1.18), and distant metastasis–free survival estimates were 78.2% and 79.2%, respectively (HR = 1.06, 95% CI = 0.86–1.31).
Lung-related adverse events of grade 2 or higher occurred in 13 patients in the irradiation group vs 5 in the no-irradiation group (odds ratio = 2.59, 95% CI = 0.97–8.12). Smaller differences in heart-related and bone-related adverse events were observed between the two groups. Death from lung cancer occurred in seven patients (0.9%) in each group.
The investigators concluded: “In this trial, chest wall irradiation did not result in higher overall survival than no chest wall irradiation among patients with intermediate-risk early breast cancer treated with mastectomy and contemporary adjuvant systemic therapy.”
Ian H. Kunkler, FRCR, of Institute of Genetics and Cancer, University of Edinburgh, Edinburgh, UK, is the corresponding author for the New England Journal of Medicine article.
Disclosure: The study was funded by the UK Medical Research Council and others. For full disclosures of all study authors, visit nejm.org.
