Background: Patients who have residual invasive carcinoma after the receipt of neoadjuvant chemotherapy for human epidermal growth factor receptor 2 (HER2)-negative breast cancer have poor prognoses. The benefit of adjuvant chemotherapy in these patients remains unclear.
Methods: We randomly assigned 910 patients with HER2-negative residual invasive breast cancer after neoadjuvant chemotherapy (containing anthracycline, taxane, or both) to receive standard postsurgical treatment either with capecitabine or without (control). The primary end point was disease-free survival. Secondary end points included overall survival.
Results: The result of the prespecified interim analysis met the primary end point, so this trial was terminated early. The final analysis showed that disease-free survival was longer in the capecitabine group than in the control group (74.1% vs. 67.6% of the patients were alive and free from recurrence or second cancer at 5 years; hazard ratio for recurrence, second cancer, or death, 0.70; 95% confidence interval [CI], 0.53 to 0.92; P=0.01). Overall survival was longer in the capecitabine group than in the control group (89.2% vs. 83.6% of the patients were alive at 5 years; hazard ratio for death, 0.59; 95% CI, 0.39 to 0.90; P=0.01). Among patients with triple-negative disease, the rate of disease-free survival was 69.8% in the capecitabine group versus 56.1% in the control group (hazard ratio for recurrence, second cancer, or death, 0.58; 95% CI, 0.39 to 0.87), and the overall survival rate was 78.8% versus 70.3% (hazard ratio for death, 0.52; 95% CI, 0.30 to 0.90). The hand-foot syndrome, the most common adverse reaction to capecitabine, occurred in 73.4% of the patients in the capecitabine group.
Conclusions: After standard neoadjuvant chemotherapy containing anthracycline, taxane, or both, the addition of adjuvant capecitabine therapy was safe and effective in prolonging disease-free survival and overall survival among patients with HER2-negative breast cancer who had residual invasive disease on pathological testing. (Funded by the Advanced Clinical Research Organization and the Japan Breast Cancer Research Group; CREATE-X UMIN Clinical Trials Registry number, UMIN000000843 .).