ASTRO 2019: Postmastectomy Radiation Therapy for HER2-Positive Breast Cancer
Posted: Friday, September 20, 2019
Postmastectomy radiation therapy appears to lower the risk of locoregional recurrence in patients with HER2-positive, node-positive breast cancer, according to an analysis of the HERA trial, which was presented at the 2019 American Society for Radiation Oncology (ASTRO) Annual Meeting (Abstract 83). However, Youssef Zeidan, MD, PhD, of the American University of Beirut Medical Center, Lebanon, and colleagues found that the magnitude of benefit from postmastectomy radiation therapy in this population is lower than in historical studies.
The analysis focused on data from the phase III, randomized HERA trial, which established the efficacy and safety of trastuzumab in HER2-positive early-stage breast cancer. A total of 1,633 patients treated with mastectomy and adjuvant trastuzumab were included; 940 patients (57.6%) received postmastectomy radiation therapy to the chest wall and regional lymphatics, and 693 patients (42.4%) did not.
After a median follow-up of 11 years, the researchers observed no significant difference in locoregional recurrence after radiation therapy in node-negative patients (hazard ratio = 1.0 [0.33–2.98], P = .99). However, patients with node-positive disease (one to three positive nodes) who received postmastectomy radiation had a locoregional recurrence rate of 2.8%, compared with 9.7% in the group that received no radiation (hazard ratio = 0.29 [0.12–0.66], P = .003). As for overall survival, again no significant differences based on receipt of postmastectomy radiation therapy were reported.
“Future randomized trials are needed to assess the role of postmastectomy radiation in HER2-positive breast cancer patients,” concluded Dr. Zeidan and colleagues.
Disclosure: The study authors reported no conflicts of interest.