[Eribulin Administration Methods to Extend the Survival Time of Patients with Advanced or Recurrent Breast Cancer, Consideringthe Relative Dose Intensity, Time to Treatment Failure, Pretreatment Regimen Number, and Tumor Subtype].

: Eribulin is evaluated as the only agent that can extend the survival time of patients with advanced or recurrent breast cancer, when used as or after third-line chemotherapy. We retrospectively analyzed the efficacy of eribulin for the treatment of advanced or recurrent breast cancer in our hospital, considering the relative dose intensity(RDI), time to treatment failure (TTF), pretreatment regimen number, and tumor subtype. Of the 36 patients who were treated with eribulin between December 2011 and August 2016, we studied 31 patients who received eribulin as a single agent. The median RDI was 0.75 (range: 0.44-1). The response rate was 22.5%, the disease control rate was 80.6%, and the clinical benefit rate was 45.2%. Overall survival(OS)was not associated with the RDI, previous regimen number, or tumor subtype; however, OS was affected by the TTF. Eribulin is a novel drug that has a different mechanism of action compared with those of conventional anticancer drugs. Therefore, prolonging the duration of eribulin administration may be more important than maintaining the RDI.