Recently several new chemotherapeutic agents have been developed and indicated for treatment of recurrent breast cancer. One of them, eribulin have improved overall survival (OS) in EMBRACE trials. On the other hand, bevacizumab has improved progression-free survival (PFS) in several clinical studies, but not extended OS in them. And there are few reports estimating these agents’ effects on OS and PFS of advanced or recurrent breast cancer patients in a real world setting.
Recurrent breast cancer patients who received chemotherapies in Toyama Breast Cancer Research Group (TBCRG) group institutes from January 2013 to March 2015 were reviewed. Kaplan-Meier method was utilized to estimate OS or PFS, and log-rank test was used to compare OS or PFS. Univariate and multivariate analyses were preformed to find significant factor(s) concerning OS.
Of 208 patients who received chemotherapies in the period mentioned, there were 157 patients who received chemotherapies using both or either of eribulin (Eri), and bevacizumab (Bev). Median age of each group using Eri/Bev were 52.4/54.6. Disease status of Eri/Bev were as follows; 68.8%/79.0% ER positive, 18.8%/11.3% HER2 positive. Metastasis of each group using Eri/Bev were observed at; 51.0%/55.2% bones, 7.3%/8.1% CNS, 56.3%/47.2% lung, and 33.3%/49.6% liver. Response rates and PFS from the starting period of Eri/Bev were 21%/75%, and 387days/297days. Multivariate COX regression analysis disclosed negative HER2 status in Eri group, and liver involvement in Bev group influenced the response rates significantly. Earlier administration of Eri shows better survival durations from primary chemotherapies (1470 days), comparison with those of Bev (1076 days). Response rate/disease control rate of pre-line chemotherapies in Eri group were 32%/57%, and not significantly diffierent from 29%/65% in Bev group, but those of post-line chemotherapies were 21%/63% in Eri group and 6%/28% in Bev group.
According to our retrospective observation analyses of group data, eribulin did not reduce the effects of subsequent chemotherapies, and improved OS of advanced or recurrent breast cancer patients. We have to reassess the value of new chemotherapeutic agents continuously.
Clinical trial identification
All authors have declared no conflicts of interest.