Use of adjuvant capecitabine in older patients with early-stage triple-negative breast cancer

Patients with triple-negative breast cancer (TNBC) who have residual disease after neoadjuvant chemotherapy (NACT) benefit from adjuvant capecitabine. Older patients are not always treated according to guidelines, likely due to concerns regarding tolerance. We examined the use of adjuvant capecitabine, its association with outcomes, and subsequent emergency room visits (ER) and hospitalizations (HSP) among older patients with early-stage TNBC.

Retrospective, observational study using data in the SEER-Medicare database. Older patients (≥ 66 years) with early-stage TNBC, diagnosed in 2010-2019, who received NACT, underwent surgery, and were prescribed adjuvant capecitabine were included. We analyzed capecitabine use, its association with overall survival and breast-cancer specific survival, and time to first ER/HSP. Logistic regression, Kaplan-Meier estimates, and Cox regression models with propensity score adjustments were used.

239 of 1,799 older patients with TNBC received adjuvant capecitabine. Capecitabine use increased from 1.3% in 2010 to 29.6% in 2019. Older age, ≥ 71 years, (OR = 0.54, 95%CI 0.32-0.92) and ≥ 2 comorbidities (OR = 0.42, 95%CI 0.2-0.9) were associated with decreased odds of receiving ≥ 6 cycles of capecitabine. Increasing number of cycles of capecitabine was associated with decreased risks of death (HR = 0.74, 95%CI 0.66-0.83) and breast cancer-specific death (HR = 0.73, 95%CI 0.61-0.89). 55 patients (23%) treated with capecitabine experienced ER/HSP.

In recent years, adjuvant capecitabine is increasingly used for patients with early-stage TNBC. Patients with older age and more comorbidities received fewer cycles of capecitabine. While one-fourth of patients had ER/HSP, receipt of more cycles was associated with better survival.