Sara J. Schonfeld, Amy Berrington de Gonzalez, Ruth M. Pfeiffer, and William F. Anderson, Department of Health and Human Services (DHHS), National Institutes of Health (NIH), National Cancer Institute, Bethesda; Kala Visvanathan, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD.
PURPOSE: Although ovarian cancer incidence rates have declined in the United States, less is known of ovarian cancer trends among survivors of breast cancer. Therefore, we examined second primary ovarian cancers after first primary breast cancer.
METHODS:Data were obtained from the Surveillance, Epidemiology, and End Results program (1973 to 2008). Standardized incidence ratios (SIRs) were calculated as the observed numbers of ovarian cancers among survivors of breast cancercompared with the expected numbers in the general population. Absolute rates were measured as the incidence rates for second primary ovarian cancer by year of diagnosis of the first primary breast cancer adjusted for age of breast cancerdiagnosis and years since diagnosis.
RESULTS:SIRs for second primary ovarian cancer were elevated over the entire study period (SIR, 1.24; 95% CI, 1.2 to 1.3), whereas the absolute rates declined with an estimated annual percentage change near 1% (-1.34% to -0.09% per year). Secular trends for second ovarian cancers were similar after estrogen receptor (ER) -positive and ER-negative breast cancers, whereas the age-specific patterns varied significantly by ER expression (P for interaction < .001). The largest SIR was among w
CONCLUSION:Persistently elevated SIRs along with decreasing absolute rates over the entire study period suggest that ovarian cancers in both the general population and survivors of breast cancer are declining in parallel, possibly because of common risk factor exposures. Analytic studies are needed to further assess the parallel overall trends and the age-specific interaction by ER expression.