Ten-Year Update on Standard Adjuvant Chemotherapy vs Capecitabine in Older Women With Early Breast Cancer
As reported in the Journal of Clinical Oncology by Muss et al, long-term findings from the phase III CALGB 49907 trial support the finding from the primary analysis—that standard adjuvant chemotherapy improved recurrence-free survival vs capecitabine in women aged 65 years or older with early breast cancer. The primary analysis, reported after median follow-up of 2.4 years, showed significant benefit of standard adjuvant therapy vs capecitabine in recurrence-free survival, the primary endpoint, and overall survival.
In the trial, 633 women aged 65 years or older were randomly assigned to standard adjuvant chemotherapy (n = 326)—consisting of physician’s choice of cyclophosphamide/methotrexate/fluorouracil for six 28-day cycles (n = 133) or cyclophosphamide/doxorubicin for four 21-day cycles (n = 184)—or capecitabine for six 21-day cycles (n = 307).
Long-Term Outcomes
The current report provides findings after a median follow-up of 11.4 years. At 10 years, recurrence-free survival was 56% in the standard-therapy group vs 50% in the capecitabine group (hazard ratio [HR] = 0.80, P = .03), breast cancer–specific survival was 88% vs 82% (HR = 0.62, P = .03), and overall survival was 62% vs 56% (HR = 0.84, P = .16).
At the time of analysis, the standard chemotherapy group had significantly improved recurrence-free survival among women with hormone receptor–negative disease (HR = 0.66, 95% confidence interval [CI] = 0.46–0.95) but not among hormone receptor–positive patients (HR = 0.89, 95% CI = 0.68–1.18).
Hazard ratios were 0.62 (95% CI = 0.32–1.22) for breast cancer–specific survival and 0.74 (95% CI = 0.50–08) for overall survival among hormone receptor–negative patients, and 0.58 (95% CI = 0.32–1.03) for breast cancer–specific survival and 0.91 (95% CI = 0.68–1.23) for overall survival among hormone receptor–positive patients.
Overall, 43.9% of patients had died at time of analysis (13.1% from breast cancer, 16.4% from causes other than breast cancer, and 14.1% from unknown causes). Second new cancers occurred in 14.7% of patients, including 16.9% of patients in the standard therapy group and 12.4% of patients in the capecitabine group. Breast cancer accounted for 10% vs 16% of all deaths in patients in the standard-therapy vs capecitabine groups (P = .045); deaths not attributable to breast cancer were reported for 17% vs 16% of patients.
The investigators concluded, “With longer follow-up, [recurrence-free survival] remains superior for standard adjuvant chemotherapy vs capecitabine, especially in patients with hormone receptor–negative disease. Competing risks in this older population dilute overall survival benefits.”
Hyman B. Muss, MD, of the University of North Carolina at Chapel Hill, is the corresponding author for the Journal of Clinical Oncology article.
Disclosure: The study was supported by grants from the National Cancer Institute and by Roche. For full disclosures of the study authors, visit jco.ascopubs.org.
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