The Impact of Treatment Preferences in Second-Line Chemotherapy on the Prognosis of HER2-Negative Metastatic Breast Cancer.

OBJECTIVE

We assessed the impact of treatment preferences in second-line chemotherapy on breast cancer prognosis using the SELECT BC study.

METHODS

The SELECT BC study was performed in patients with HER2-negative metastatic breast cancer treated with initial chemotherapy. From these patients, 618 were assigned to 2 groups (S-1 group, 309; taxane group, 309). The S-1 and taxane groups were each subdivided into 3 groups: crossover group, protocol-recommended group, and other group, and the analysis of overall survival (OS) was performed using Cox regression with inverse probability weighting, to adjust for postrandomization confounding.

RESULTS

In the taxane group, the OS of the crossover group (39.6 months) was better than that of the protocol-recommended group (35.7 months) and the other chemotherapy group (36.9 months) (vs. the protocol-recommended group, HR 0.72 [95% CI 0.52-0.98], p = 0.037; vs. the other chemotherapy group, HR 0.71 [95% CI 0.43-1.18], p = 0.183). In the S-1 group, there was no statistically significant difference in OS between the 3 groups.

CONCLUSION

The study of the combination of first-line chemotherapy and second-line chemotherapy showed that S-1 might be recommended as a second-line chemotherapy in patients in whom taxane was the primary chemotherapy.