Objective: To assess incidence during a 10-year study period and to identify and discuss clinical relevance for prognostic factors of survival within a cohort of Norwegian ovarian cancer patients.
Methods: Incidence and prognostic factors of survival within a population-based cohort of ovarian cancer patients from one health region in Norway were examined over the 10-year period 1987 through 1996. A total of 571 histologically verified cases of primary ovarian cancer originally registered either in the Cancer Registry of Norway or in the hospital's discharge registers were included in the study. Pearson chi(2) test was used in univariate analyses of cofactors by 5-year survival, and Kaplan-Meier survival curves were computed and tested statistically by the log rank test. A multivariable proportional hazard model (Cox) was applied to assess the prognostic significance of the different covariates.
Results: The incidence and crude 5-year survival remained stable over the 10-year study period. The standardized incidence rate for the time periods 1987-1991 and 1992-1996 was 11.9/100,000 and 12.5/100,000, respectively. The crude 5-year survival rate for the cohort was 39%, whereas median survival was 32 months. Cox multivariable regression analysis showed that the only independent significant prognostic factors were International Federation of Gynecology and Obstetrics stage (P <.001), size of residual tumor at the end of primary surgery (P <.001), and age at diagnosis (P <.01). Variables such as time period, histologic type and grade, treating hospital, comorbidity, or CA 125 were insignificant in predicting 5-year survival.
Conclusion: The results underline the importance of improved surgical management of ovarian cancer, as residual tumor is the only prognostic factor achievable.