Standard adjuvant chemotherapy remained superior to capecitabine in older patients with early breast cancer, according to long-term follow-up results from a randomized study.
“We previously reported the primary analysis after a median follow-up of 2.4 years,” wrote Hyman B. Muss, MD, of the University of North Carolina, Chapel Hill, and his colleagues in Journal of Clinical Oncology.
“We now assess the risks and benefits of treatment after a median follow-up time of 11.4 years,” they said.
The Cancer and Leukemia Group B 49907 trial included 633 women aged 65 years and over with early breast cancer. Study patients were randomly assigned to receive either standard adjuvant chemotherapy (either cyclophosphamide and doxorubicin, methotrexate and fluorouracil, or cyclophosphamide) or capecitabine.
The study was designed to evaluate noninferiority of capecitabine versus standard chemotherapy. The primary outcome measured was recurrence-free survival (RFS); overall survival (OS) was included as a secondary endpoint.
After analysis, the researchers reported that the 10-year RFS rates were 56% with standard chemotherapy versus 50% with capecitabine (hazard ratio, 0.80; P = .03).
In addition, the breast cancer–specific survival rates were 88% and 82% in patients treated with standard chemotherapy, compared with capecitabine, respectively (hazard ratio, 0.62; P = .03). OS rates were 62% and 56% in the same groups (HR, 0.84; P = .16).
“With longer follow-up, RFS remains superior for standard adjuvant chemotherapy versus capecitabine, especially in patients with hormone receptor–negative disease,” Dr. Muss and his colleagues wrote.
The researchers acknowledged that the presence of comorbidities in this older population may diminish overall survival benefits.
“Optimally, we must increase the number of older patients in cancer clinical trials to have accurate data on outcomes, especially toxicity, for newer agents,” they concluded.
The study was funded by the National Cancer Institute of the National Institutes of Health. The authors reported financial affiliations with Boehringer Ingelheim, Celgene, Genentech, Novartis, Puma Biotechnology, Pfizer, Sanofi, Seattle Genetics, and several others.
SOURCE: Muss HB et al. J Clin Oncol. 2019 Jul 24. doi: 10.1200/JCO.19.00647.