[A multicenter clinical study for the comparison of S-1 versus capecitabine in the treatment of advanced breast cancer].

Objective: To investigate the safety, efficacy and prognostic factors of S-1 versus capecitabine in patients with advanced breast cancer (ABC). Methods: From January 1, 2012 to December 31, 2014, 154 ABC patients with pathological diagnosis were separated into two groups: S-1 with or without the 3rd generation chemotherapy drug (group S-1) and capecitabine with or without the 3rd generation chemotherapy drug (Group capecitabine). The efficacy, side effects and prognostic factors were compared between the two groups. Results: There were 70 patients in group S-1 and 84 patients in group capecitabine. The objective response rates (ORR) were 31.4% (22/70) in group S-1 and 28.6% (24/84) in group capecitabine. The disease control rates (DCR) were 74.3% (52/70) and 83.3% (70/84), respectively. There were no significant differences in DCR and ORR between two groups (P>0.05). The DCR of patients treated with capecitabine monotherapy was significantly higher than that of S-1 monotherapy [94.4%(17/18) and 64.0%(16/25), P=0.028]. The median PFS was 7.5 and 8.9 months for the patients in the group S-1 and group capecitabine, with no statistically significant difference (P=0.423). The 1-year survival rates of group S-1 and group capecitabine were 81.4% and 66.7%, respectively, with no significant differences(P=0.020). Univariate analysis showed that ER and/or PR status (P=0.004), T stage (P=0.041), and molecular typing (P=0.046) were associated with PFS. Multivariate analysis showed ER and/or PR status (P=0.034) was an independent prognostic factor related with PFS. The incidence of hemoglobin reduction was 14.3% (10/70) and 36.9% (31/84) in the group S-1 and group capecitabine, and the differences were statistically significant (P=0.002). There was no significant difference in the incidence of leukopenia, neutropenia, thrombocytopenia and hand-foot syndrome between the two groups(P>0.05). Conclusions: S-1 and capecitabine are both effective for advanced breast cancer. Neither ORR nor DCR were significantly different between these two groups. The incidence of gastrointestinal reactions and thrombocytopenia of S-1 was slightly lower than that of capecitabine.