The effect of hospital operative volume, residual tumor and first-line chemotherapy on survival of ovarian cancer - a prospective nation-wide study in Finland.

Objective: Our recent prospective, nation-wide study indicated better surgical outcome in ovarian cancer patients operated at university hospitals compared to other hospitals. Here we report how this is reflected in 5-year cancer-specific survival (CSS).

Methods: Detailed 5-year follow-up data were obtained on 275 patients by using a special questionnaire, and the data were verified from the Finnish Cancer Registry data. The hospitals were categorized to university and other hospitals and by the number of operations performed in 1999 (<10, 10-20, or >20 operations). Data were analyzed using the Cox's proportional hazards regression analysis.

Results: The study population covered 90% of the epithelial ovarian cancer patients operated in 1999, in Finland. Eighty-two percent of the patients received platinum-based chemotherapy. The percentage of patients treated with a platinum-taxane combination was higher in university hospitals (63% vs. 49%, P=0.037). The 5-year CSS was 56% and the median disease-free survival (DFS) was 33 months. In multivariate analysis prognostic factors for CSS were stage (P=0.0027), residual tumor (P=0.0001), and primary chemotherapy (P<0.0001). Hospital operative volume was associated with residual tumor (P=0.027). When hospital operative volume increased with ten patients per year, the odds ratio for no residual disease was 1.203 (95% CI 1.022-1.417).

Conclusion: FIGO stage, residual tumor, and primary chemotherapy are significant prognostic factors for ovarian cancer. Hospital volume is associated with residual tumor. The results favor performance of ovarian cancer surgery in hospitals with higher operative volumes.