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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Thursday, January 2, 2025
Ian Kunkler, MA, MB, BChir, of the University of Edinburgh, and colleagues suggested that the role of postmastectomy radiotherapy in influencing survival among patients with intermediate-risk, node-positive breast cancer remains unknown. During the 2024 San Antonio Breast Cancer Symposium (SABCS; Abstract GS2-03), these investigators presented the results of the BIG 2-04 MRC SUPREMO trial, which evaluated the impact of chest wall irradiation after mastectomy on 10-year overall survival in this patient population.
“This study demonstrates that chest wall irradiation after a mastectomy has no influence on 10-year overall survival for patients with intermediate-risk breast cancer,” said Dr. Kunkler in an American Association for Cancer Research press release. “The results are important considerations for shared decision-making conversations between patients and clinicians, as many patients eligible for postmastectomy chest wall irradiation may not require the treatment.”
This phase III, international, randomized controlled trial enrolled 1,607 patients with breast cancer who had one to three positive nodes and were considered at intermediate risk for locoregional recurrence. Participants were randomly assigned to receive (n = 808) or not to receive (n = 799) chest wall irradiation postmastectomy. Chest wall irradiation was administered at a total dose of 50 Gy in 25 daily fractions over 5 weeks or a radiobiologic equivalent.
The median follow-up was 9.6 years, at which time chest wall irradiation did not appear to affect overall survival in any subgroup (hazard ratio [HR] = 1.04). In addition, there was no impact of radiotherapy on overall survival between patients with and without positive lymph nodes (HR = 0.82). Chest wall recurrences were reported in 29 patients across both treatment groups, and chest wall recurrence-free survival rates were 98.8% and 97.1% in the irradiation and nonirradiation arms, respectively. Of note, chest wall irradiation reduced chest wall recurrence to some degree (HR = 0.45), but there was no demonstrable differential treatment effect across subgroups, according to the investigators.
Disclosure: For full disclosures of the study authors, visit sabcs.org.
2024 San Antonio Breast Cancer Symposium
