In an analysis reported in The Lancet Oncology, Sara M. Tolaney, MD, MPH, and colleagues described 10-year survival outcomes from the phase II APT trial assessing adjuvant paclitaxel/trastuzumab in patients with node-negative, HER2-positive breast cancer.
The U.S. multicenter trial included a total of 406 patients with small (≤ 3 cm) node-negative disease enrolled between October 2007 and September 2020. They received adjuvant treatment with weekly paclitaxel at 80 mg/m² and trastuzumab at a loading dose of 4 mg/kg followed by 2 mg/kg weekly for 12 weeks, followed by trastuzumab weekly at 2 mg/kg or once every 3 weeks at 6 mg/kg for 40 weeks to complete a full year of treatment with trastuzumab. The primary endpoint was 3-year invasive disease–free survival.
Sara M. Tolaney, MD, MPH
Median follow-up was 10.8 years (interquartile range = 7.1–11.4 years).
A total of 31 invasive disease–free survival events were observed: 6 (19.4%) were locoregional ipsilateral recurrences, 9 (29.0%) were new contralateral breast cancers, 6 (19.4%) were distant recurrences, and 10 (32.3%) were all-cause deaths.
Ten-year invasive disease–free survival was 91.3% (95% confidence interval [CI] = 88.3%–94.4%), and the 10-year recurrence-free interval (freedom from distant recurrence, death from breast cancer, and invasive locoregional recurrence) was 96.3% (95% CI = 94.3%–98.3%).
Ten-year overall survival was 94.3% (95% CI = 91.8%–96.8%), and 10-year breast cancer–specific survival was 98.8% (95% CI = 97.6%–100%).
In an exploratory analysis using the HER2DX genomic tool, the HER2DX risk score as a continuous variable was significantly associated with invasive disease–free survival (hazard ratio [HR] per 10-unit increment = 1.24, 95% CI = 1.00–1.52, P = .047) and recurrence-free interval (HR per 10-unit increment = 1.45, 95% CI = 1.09–1.93, P = .011).
The investigators concluded, “Adjuvant paclitaxel and trastuzumab is a reasonable treatment standard for patients with small, node-negative, HER2-positive breast cancer. The HER2DX genomic tool might help to refine the prognosis for this population.”
Dr. Tolaney, of the Department of Medical Oncology, Dana-Farber Cancer Institute, is the corresponding author for The Lancet Oncology article.
Disclosure: The study was funded by Genentech. For full disclosures of the study authors, visit thelancet.com.The content in this post has not been reviewed by the American Society of Clinical Oncology, Inc. (ASCO®) and does not necessarily reflect the ideas and opinions of ASCO®.