Effect of tumor type on response to adjuvant platinum-based chemotherapy and prognosis in patients with stage II-IV epithelial ovarian carcinoma.

Objectives: To evaluate the effect of histological subtype on oncological outcome and adjuvant platinum-based chemotherapy response in patients with epithelial ovarian cancer (EOC).

Material and methods: The study group was created with stage II-IV EOC patients. Progression-free survival (PFS) and disease-specific survival (DSS) estimates were determined by using the Kaplan-Meier method. The log-rank test and cox proportional hazards model were performed.

Results: A total 396 patients were included the study. Tumor type was serous in 332 (83.8%). Two hundred and thirty-one patients (58.3%) had maximal cytoreduction. Three hundred and twenty-seven (82.6%) patients received complete clinical response. Refractory disease was present in 69 (17.4%) patients. In patients with complete clinical response, 183 (56%) patients recurred. Five-year PFS was 32% in serous group and 31% in non-serous group (p = 0.755). Five-year DSS was 78% in serous group and 87% in non-serous group (p = 0.084). On multivariate analysis, recurrence rates 1.959 times (95% CI: 1.224-3.085; p = 0.004), death rates 2.624 times (95% CI: 1.328-5.185; p = 0.005) higher in patients with optimal cytoreduction than patients with maximal cytoreduction, respectively.

Conclusions: Although the rate of maximal cytoreduction was higher in patients with non-serous tumor type, the rate of refractory disease was higher after adjuvant chemotherapy. However, the recurrence rate was higher in serous tumor type. Survival rates were similar in serous and non-serous tumor types. Maximal cytoreduction was an independent predictor factor for survival. Maximal cytoreduction should be the main target in EOC.