Standard Adjuvant Chemo Trumps Capecitabine in Older Women With Breast Cancer
In a recent clinical trial of older patients with breast cancer, standard adjuvant chemotherapy resulted in superior long-term recurrence-free survival (RFS) compared with capecitabine, especially among those with hormone receptor–negative disease (J Clin Oncol. 2019 Jul 24. Epub ahead of print).
Evaluating Breast Cancer in Older Age
Citing and underrepresentation of older women with breast cancer in clinical trials, Hyman B. Muss, MD, University of North Carolina Lineberger Comprehensive Cancer Center, Chapel Hill, and colleagues created the Cancer and Leukemia Group B 49907 clinical trial to focus on women aged ≥65 years with early breast cancer.
A total of 633 women were enrolled and randomized to receive standard adjuvant chemotherapy (physician's choice of cyclophosphamide, methotrexate, and fluorouracil or cyclophosphamide and doxorubicin) or capecitabine. The primary end point of the trial was RFS, and an adaptive Bayesian design was used to evaluate the noninferiority of capecitabine.
“We previously reported the primary analysis after a median follow-up of 2.4 years,” Dr Muss et al said. They also showed that standard adjuvant chemotherapy led to significant improvements in RFS and overall survival versus capecitabine.
The data presented here reflect a longer median follow-up of 11.4 years.
RFS Maintained Over Extended Follow-Up
According to the long-term findings, RFS was maintained significantly longer for patients treated with standard chemotherapy versus capecitabine.
Among patients treated with standard chemotherapy versus capecitabine, the 10-year RFS rates were 56% and 50%, respectively (hazard ratio [HR], 0.80; P = .03). The overall survival rates were 62% and 56%, respectively (HR, 0.84; P = .16), and breast cancer–specific survival rates were 88% and 82%, respectively (HR, 0.62; P = .03).
Of note, standard chemotherapy maintained its superiority over capecitabine with longer follow-up in patients with hormone receptor–negative (HR, 0.66; P = .02) but not hormone receptor–positive disease (HR, 0.89; P = .43).
Across the total study population, 43.9% of patients have died, including 13.1% who died because of breast cancer, 16.4% due to other causes, and 14.1% from unknown causes. Approximately 14% of patients had second nonbreast cancers.
“With longer follow-up, RFS remains superior for standard adjuvant chemotherapy versus capecitabine, especially in patients with hormone receptor-negative disease,” Dr Muss and colleagues said.
“Competing risks in this older population dilute overall survival benefits,” they concluded.—Hina Khaliq