Two for good measure: Six versus eight cycles of carboplatin and paclitaxel as adjuvant treatment for epithelial ovarian cancer

Abstract

Introduction. Although the standard of care for advanced epithelial ovarian cancer (EOC) is six cycles (6C) of platinum-taxane (PT), there have been no studies on the optimal duration of treatment in the era of adjuvant taxanes. At our center, some women receive eight cycles (8C) of PT, based on physician judgment. We were interested in evaluating the outcomes of women treated with 8C of PT for EOC as compared to a cohort who received 6C. Methods. We retrospectively identified women with Stage III or IV EOC between 1998 and 2003 who received 6C or 8C of PT. The endpoints were disease-free (DFS) and overall survival (OS). CA-125 response was defined as a decrease in CA-125 of 50% in four serial samples or of 75% over three samples. Results. One hundred and twenty-two women met criteria for inclusion; 84 received 6C, and 38 received 8C. Comparing the cohorts receiving 6C versus 8C, 71% versus 26% were optimally debulked ( P < 0.01). 79 patients were evaluable by CA-125 (52 6C/27 8C), and all responded. 88% receiving 6C and 81% receiving 8C normalized their CA-125 at end of treatment ( P = 0.20). The proportion with a normal CA-125 at Cycle 2 was 29% versus 12%, respectively ( P = 0.15) and, at Cycle 4, was 88% versus 36%, respectively ( P < 0.01). DFS was 13 months with 6C and 8 months with 8C ( P = 0.01). OS was 31 versus 23.5 months ( P = 0.02), respectively. When the survival analysis is restricted to suboptimal debulked patients only, the DFS is 12.5 versus 8 months ( P = 0.02), and OS is 32 versus 26.5 months ( P = 0.15), respectively. Conclusions. Two further cycles of PT did not improve DFS or OS for patients with advanced EOC. Patients who do not achieve remission after 6C are unlikely to benefit from additional chemotherapy using the same agents and should be considered for clinical trials involving novel agents with different mechanisms of action.