(HealthDay News) – Primary ovarian cancer incidence is declining in the United States, both among the general population and among breast cancer survivors, according to research published online Jan. 2 in the Journal of Clinical Oncology.
Sara J. Schonfeld, PhD, MPH, from the National Institutes of Health in Bethesda, MD, and colleagues analyzed data from the Surveillance, Epidemiology, and End Results program (1973–2008) to examine the incidence of second primary ovarian cancers among breast cancer survivors.
The researchers found that, over the entire study period, the standardized incidence ratios (SIRs) for second primary ovarian cancer were elevated (SIR, 1.24), while the absolute rates decreased by about 1% per year. Similar secular trends were observed for second ovarian cancers following estrogen receptor (ER)-positive and ER-negative breast cancers, although there were significant variations in the age-specific patterns based on ER expression. Women aged <50 years with ER-negative breast cancer had the largest SIR (SIR, 4.35).
“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,” the authors write. “Analytic studies are needed to further assess the parallel overall trends and the age-specific interaction by ER expression.”