Three versus six cycles of adjuvant platinum-based chemotherapy in early stage clear cell ovarian carcinoma – A multi-institutional cohort

Abstract Objectives To determine if 6 versus 3 cycles of adjuvant platinum-based chemotherapy with or without taxane impacts survival in early stage ovarian clear cell carcinoma (OCCC). Methods We retrospectively identified all cases of stage I and II OCCC treated at 5 institutions from January 1994 through December 2011. Patients were divided into 2 groups: those who received 3 versus 6 cycles of adjuvant chemotherapy. Our cohort consisted of 210 patients with stage IA-II disease, 116 of whom underwent full surgical staging. Cox proportional hazards regression and Kaplan-Meier analyses were performed to evaluate progression-free (PFS) and overall survival (OS) between groups. Results Among 210 eligible patients, the median age was 53 years (range 30–88). The majority of patients were Caucasian (83.8%). All patients received adjuvant chemotherapy with 90% receiving carboplatin and paclitaxel. Thirty-eight (18.1%) patients received 3 cycles, and 172 (81.9%) patients received 6 cycles of adjuvant treatment. Recurrence rate was comparable between groups (18.4% vs. 27.3% for 3 vs. 6 cycles, p = 0.4). There was no impact of 3 versus 6 cycles of chemotherapy on PFS (hazard ratio [HR] 1.4; 95% confidence interval [CI] 0.63–3.12, p = 0.4) or OS (HR 1.65; 95% CI 0.59–4.65, p = 0.3) on univariate analysis. There was no benefit to more chemotherapy in stratified analysis by stage nor on multivariate analysis adjusting for the impact of stage. Subgroup analysis of surgically staged patients also showed no difference in survival between 3 versus 6 cycles of chemotherapy. Conclusions Three cycles of platinum with or without taxane adjuvant chemotherapy were comparable to 6 cycles with respect to recurrence and survival in patients diagnosed with early stage ovarian clear cell carcinoma in this retrospective multi-institutional cohort. Condensation Three cycles of platinum with or without taxane adjuvant chemotherapy are comparable to 6 cycles with respect to recurrence and survival in patients diagnosed with early stage ovarian clear cell carcinoma in this retrospective multi-institutional cohort.