Incidence and factors associated with synchronous ovarian and endometrial cancer: A population-based case-control study

ObjectiveTo estimate the incidence of synchronous endometrial cancer (EC) and ovarian cancer (OC) in the female population, among all women with EC, and in women under 50 years of age with EC, and to identify factors associated with synchronous EC/OC.MethodsAll cases of synchronous EC/OC and EC diagnosed in women residing in Olmsted County, Minnesota between 1/1/1945 and 12/31/2008 were identified. Incidence was estimated using the population denominator from decennial census data, corrected for hysterectomy prevalence. A case-control study using 15 identified cases (EC/OC) and 45 controls (EC alone) was performed.ResultsThe incidence of synchronous EC/OC and EC (age-adjusted to the 2000 US female total and corrected for hysterectomy prevalence) in 1945–2008 was 0.88 and 30.3 per 100,000 person-years, respectively. Among women under 50 years of age, the corrected incidence of EC/OC and EC was 0.51 and 5.1 per 100,000 person-years, respectively. Among all women with EC, 3.1% had a synchronous OC compared to 9.4% of women under 50 years of age with EC. Patients with synchronous EC/OC were more likely than those with EC alone to present with a pelvic mass (57.1% vs. 8.9%, p < 0.001). Patients with EC alone were more likely to have used oral contraceptive pills (OCPs) than synchronous EC/OC cases (22.7% vs 0%; Odds ratio, 0.10; 95% CI, < 0.01–0.87).ConclusionAlthough the incidence of synchronous EC/OC in the general population is lower than previously reported, nearly 1 in 10 women diagnosed with EC under 50 years of age will have a synchronous OC.

► The incidence of synchronous endometrial and ovarian cancer in Olmsted County is found to be smaller than that reported in other studies.
► Women with endometrial cancer under the age of 50 may have a 1 in 10 risk of developing a synchronous ovarian cancer.
► Oral contraceptive pills may be protective of synchronous endometrial and ovarian cancer development; however, larger studies are needed to investigate this further.