Efficacy of different dosing schedules of capecitabine for metastatic breast cancer: a single-institution experience.

Purpose Capecitabine is widely used as a single agent on a 21-day cycle in the management of metastatic breast cancer (MBC). Our primary objective was to compare the standard dosing of capecitabine (Arm A: days 1-14 on 21-day cycle) to biweekly dosing (Arm B: days 1-7 and 15-21 on 28-day cycle) using retrospective data analysis. Methods 166 patients with MBC treated with single agent capecitabine at The Ohio State University from 2002 to 2014 were considered eligible. Median time to treatment failure (TTF) and overall survival (OS) were estimated using Kaplan-Meier (KM) methods. KM curves were compared using log-rank tests with Holm's correction for multiplicity. Results Patients were grouped by dose schedule into one of three arms: Arm A (21-day cycle; capecitabine given at 1000 mg/m2 orally, twice daily on days 1-14 of 21-day cycle); Arm B (28-day cycle; capecitabine given at 1000 mg/m2 orally, twice daily on days 1-7 and 15-21 of 28-day cycle); and Arm C (changeover regimen where patients started on the 21-day cycle, but changed to a 28-day cycle for tolerability). No difference was found in TTF or OS for patients with MBC between those who received capecitabine on either standard dosing (Arm A) and those on a biweekly cycle (Arm B or C). Overall, 41% of patients required dose reduction. Conclusions Our single institution experience showed that alternate dosing of capecitabine (biweekly, 28-day cycle) may be a reasonable alternative to standard 21-day cycle with similar efficacy and fewer dose reductions.