Capecitabine In Operable Triple Receptor Negative Breast Cancer: A Subgroup Analysis Of A Randomized Phase Ill Trial

292 Background: Recent data suggest that patients with operable triple negative breast cancer (TNBC) may derive greater benefit from the addition of capecitabine to anthracycline-taxane regimens. Methods: We examined pathological complete response (pCR), relapse-free survival (RFS) and overall survival (OS) in patients with TNBC randomized to paclitaxel 80mg/m2 weekly (WP) x 12 followed by fluorouracil (500mg/m2), epirubicin (100mg/m2), cyclophosphamide (500mg/m2) every 3 weeks x 4 cycles (FEC) vs. docetaxel (75mg/m2) 3 weekly and capecitabine D1-14 (1500mg/m2 daily; DX) followed by FEC. Patients were stratified by timing of chemotherapy (preoperative vs. adjuvant). Results: 149 patients with TNBC comprising 25% of all patients randomized (N=601). Median age; 49 years (IQR; 41 to 55). The number and proportion of patients by stage were; I (n=32: 21.5%), IIA (n=72: 48.3%), IIB (n=34: 22.8%), IIIA (n=9: 6.0%) and IIIC (n=2; 1.3%). Preoperative therapy was administered to 58 patients (39%) and adjuvant to 91 (61%). There were 17 events (21%) in the DX arm and 10 events (15%) in the WP arm (P=0.36) including 11 distant recurrences in the DX arm and 9 in the WP arm (P=0.99). We observed a pCR in 11 patients (37%) and 10 (36%) in the DX and WP arms respectively (P=0.94). The odds ratio for pCR for patients with TNBC given DX vs. WP was 0.98 (95% CI; 0.33 to 2.80: P=0.94). At 50-months median follow-up the RFS and OS in patients with TNBC randomized to DX or WP was 77% (66 to 86%) and 83% (73 to 92%) (P=0.41) and 78% (67 to 87%) and 87% (77 to 95%) (P=0.16) respectively. RFS and OS for WP vs. DX for non-TNBC was 93% (87 to 95%) and 92% (88 to 96%) (p=0.91) and 96% (92 to 98%) and 97% (94 to 99%) for WP and DX respectively (P=0.39). Conclusions: In this unplanned subgroup analysis there was no difference in pCR, RFS or OS in patients with operable TNBC randomized to WP or DX however, power is limited and should be considered when interpreting these data.