Population Distribution of Lifetime Risk of Ovarian Cancer in the United States

abstract

Background: 
In U.S. women, lifetime risk of ovarian cancer is 1.37%, but some women are at a substantially lower or higher risk than this average.

Methods:
We have characterized the distribution of lifetime risk in the general population.
Published data on the relative risks and their variances for five well-accepted risk and protective factors for ovarian cancer, oral contraceptive (OC) use, parity, tubal ligation, endometriosis and first degree family history of ovarian cancer in conjunction with a genetic risk score using genome-wide significant common, low penetrance variants were used. The joint distribution of these factors (i.e., risk/protective factor profiles) were derived using control data from four US population-based studies, providing a broad representation of women in the US.

Results: A total of 214 combinations of risk/protective factors were observed and the lifetime risk estimates ranged from 0.35% (95% CI 0.29-0.42) to 8.78% (95% CI 7.10-10.9). Among women with lifetime risk ranging from 4-9%, 73% had no family history of ovarian cancer; most of these women had a self-reported history of endometriosis.

Conclusions:
Profiles including the known modifiable protective factors of OC use and tubal ligation were associated with a lower lifetime risk of ovarian cancer. OC use and tubal ligation were essentially absent among the women at 4-9% lifetime risk.

Impact:
This work demonstrates that there are women in the general population who have a much higher than average lifetime risk of ovarian cancer. Preventive strategies are available. Should effective screening become available, higher than average risk women can be identified.