Capecitabine is an active agent for advanced breast cancer, and is frequently selected for therapy either as a single agent or as a partner in a combination regimen, yet little is known about its efficacy as adjuvant treatment of early breast cancer. The Finland Capecitabine Trial (FinXX) evaluated whether integration of capecitabine into an adjuvant regimen that contains a taxane, an anthracycline, and cyclophosphamide improves outcome in early breast cancer.

The study involved women with axillary node–positive or high-risk node-negative breast cancer who were randomised to receive either three cycles of docetaxel and capecitabine (TX) followed by three cycles of cyclophosphamide, epirubicin, and capecitabine (CEX; n = 753) or three cycles of docetaxel (T) followed by three cycles of cyclophosphamide, epirubicin, and fluorouracil (CEF; n = 747). The primary end point was recurrence-free survival (RFS).

During a median follow-up time of 59 months:

• 214 RFS events occurred (local or distant recurrences or deaths; TX/CEX, n = 96; T/CEF, n = 118).

• RFS was not significantly different between the groups (hazard ratio [HR], 0.79; 95% CI, 0.60 to 1.04; p = 0.087; 5-year RFS, 86.6% for TX/CEX vs. 84.1% for T/CEF).

• 56 patients in TX/CEX group died during the follow-up vs. 75 patients assigned to T/CEF (HR, 0.73; 95% CI, 0.52 to 1.04; p = 0.080).

• In exploratory analyses, TX/CEX improved breast cancer–specific survival (HR, 0.64; 95% CI, 0.44 to 0.95; p= 0.027) and RFS in women with triple-negative disease and in women who had more than three metastatic axillary lymph nodes at the time of diagnosis.

• TX/CEX was associated with more capecitabine related toxicity including stomatitis, hand-foot syndrome, nail changes, and diarrhoea, whereas T/CEF was associated with more frequent neutropenia, febrile neutropenia, infection with neutropenia, myalgia, and amenorrhoea, probably as a result of the higher docetaxel dose.

• 6 patients died during chemotherapy possibly from a treatment-related cause (TX/CEX, n=4; T/CEF, n=2).

• Patients assigned to TX/CEX discontinued the scheduled treatment more often than patients assigned to T/CEF (178 [24%] vs. 23 [3%] patients, respectively; p< 0.001), most commonly as a result of adverse events.

The researchers conclude that the final results of the FinXX trial show that the addition of capecitabine to a chemotherapy regimen containing docetaxel, epirubicin, and cyclophosphamide did not significantly improve RFS or overall survival compared with docetaxel followed by CEF in early breast cancer.