Ten-year outcomes of metronomic capecitabine as extended adjuvant chemotherapy for early triple-negative breast cancer

In the phase 3 SYSUCC-001 trial at 13 centers in China patients with early triple-negative breast cancer (TNBC; T1b-3 N0-3c M0) who had completed surgery and standard adjuvant therapy were randomized 1:1 to receive oral metronomic capecitabine 650 mg/m2 twice daily for one year (n=221) or observation (n=213). Ten-year follow-up results of the trial have now been published. The median duration of follow-up was 16.0 months (IQR 96.0-134.8). The 10-year disease-free survival rate (primary endpoint) was 78.1% in the capecitabine group versus 66.6% in the observation group (HR 0.61; p=0.0074); the 10-year overall survival rate was not significantly different between the two groups (82.4% versus73.3%; HR 0.67; p=0.058); the 10-year disease-free survival rates were 78.1% versus 66.5% (HR 0.61; p=0.0075); and the 10-year locoregional recurrence-free survival rates were 81.6% versus 69.9% (HR 0.60; p=0.011). Patients with FOXC1-high tumors showed a survival advantage with capecitabine versus observation; patients with FOXC1-low tumors showed no benefit with capecitabine versus observation. The authors conclude that extended metrononic adjuvant capecitabine provided durable disease-free survival benefit in early TNBC.