Effects of adjuvant chemotherapy in T1N0M0 triple-negative breast cancer

Patients with T1N0M0 breast cancers are considered to have an excellent prognosis, even in triple-negative breast cancer (TNBC), which is often associated with diminished recurrence-free survival (RFS) and overall survival. Chemotherapy remains the only adjuvant treatment for TNBC, but evidence that adjuvant chemotherapy is beneficial for stage T1N0M0 TNBC patients is limited. In this study, we aimed to evaluate the effect of adjuvant chemotherapy and the benefit of taxanes in T1N0M0 TNBC patients.

A cohort of 354 consecutive patients with newly diagnosed T1N0M0 TNBC between January 2008 and December 2015 were included from the Fudan University Shanghai Cancer Center. Univariate and multivariate survival analyses were performed to compare patients treated with adjuvant chemotherapy with/without taxane addition.

Median follow-up was 45 months. Chemotherapy was used in 92.4% of patients. The 5-year estimated RFS rates of patients with and without adjuvant chemotherapy were 94.5% and 83.6%, respectively. In multivariate analysis, adjuvant chemotherapy and a lack of lymphovascular invasion were associated with a significant benefit for RFS. A significant RFS benefit from adjuvant chemotherapy was observed in T1c (hazard ratio, HR = 0.24, 95% CI [0.08-0.76], P = 0.014) but not in T1b (HR = 0.32, 95% CI [0.03-3.18], P = 0.330) subgroups. Addition of taxane to an anthracycline-based regimen was not significantly associated with improved RFS in T1N0M0 TNBC patients.

Adjuvant chemotherapy improves recurrence-free survival in T1c TNBC patients but not in T1b. Anthracycline-based taxane-free regimens might be sufficient to achieve RFS benefits in T1N0M0 TNBC patients.