Why have ovarian cancer mortality rates declined? Part II. Case-fatality.

In the United States, the age-adjusted mortality rate from ovarian cancer declined by 8% from 1975 to 1991 and by 18% from 1992 to 2011. A decline in the incidence rate of ovarian cancer paralleled the decline in mortality (described in Part I). The decline in mortality might also be due to a reduced proportion of ovarian cancer patients who die from their cancer (case-fatality). Here, we examine rates of ovarian cancer case-fatality from the Surveillance Epidemiology and End Results (SEER) registry database, and we consider to what extent advances in treatment also contribute to the observed decline in mortality. From 1973 to 1999, the five-year case-fatality rate for women with ovarian cancer fell by 7.5%, whereas the 12-year case-fatality rate fell by only 1.2%. The declines in five-year case-fatality corresponded in time with the introduction and expansion in use of cis-platinum and paclitaxel in clinical practice. However, modest declines in 12-year case-fatality indicate that the introduction of chemotherapy has not contributed to the decline in mortality. Developments in the last two decades include targeted therapies, aggressive surgical techniques, the use of neoadjuvant chemotherapy and intraperitoneal chemotherapy. The impact of these treatment modalities on ovarian cancer mortality still needs to be evaluated.