The Significance of Combination Chemotherapy in Epithelial Ovarian Cancer

Objective Since the publication of International Collaborative Ovarian Neoplasm 3, various practice patterns have evolved with respect to practice patterns and survival among women with epithelial ovarian cancer in British Columbia, Canada. The objectives of this study were to evaluate different strategies for first-line chemotherapy in ovarian cancer and to determine their effect on survival at a population level. Methods and Materials This was a retrospective population-based cohort study of 854 women with epithelial ovarian cancer in British Columbia from 2005 to 2008. Details were ascertained on stage, grade, histotype, performance status, surgeon type, extent of debulking, first-line chemotherapy including type and number of cycles, and cause and date of death. A Cox regression model was used to evaluate the association of covariates on overall survival. Results Of the 817 women eligible for chemotherapy, 729 (89.2%) received treatment, including 106 (14.5%) women who received single-agent carboplatin and 623 (85.5%) women who received combination platinum-based chemotherapy. Chemotherapy was evaluated as a time-varying covariate. Median numbers of single-agent carboplatin and combination chemotherapy cycles were 5 (range, 1-11) and 6 (range, 1-12), respectively. After adjustment for demographic, disease, and treatment factors, the covariates significantly associated with survival were stage, performance status, extent of debulking, and chemotherapy type. Single-agent carboplatin had a mortality hazards ratio of 5.15 (95% confidence interval, 2.39-11.11) relative to combination chemotherapy. Conclusions In this population-based study, first-line platinum-based combination chemotherapy was associated with improved survival compared with single-agent carboplatin after adjustment for covariates in ovarian cancer. Higher rates of combination chemotherapy may improve outcomes at a population level.