Risk Factors:

Ovarian cancer is the fifth most common malignancy in British Columbia women with a crude incidence rate of 17.1 per 100,000. The majority of the cases (about 90%) are of epithelial origin. The incidence rate has remained relatively stable over the past 30 years as has the 5-year relative survival, which is about 35% (Weiss et al, 1996).

Established risk factors for epithelial malignancies are reproductive and genetic in nature; an excellent review is given by Kelsey and Whittemore (1994). Higher risks have been observed in women with no children or with low numbers of live births. An increased risk of developing ovarian cancer has been seen with the use of fertility drugs, although not all studies have found this. A family history of breast cancer or ovarian cancer is also a risk factor. In addition, a diet with high levels of saturated fat may increase risk. There is also evidence that exposure to asbestos increases risk of ovarian cancer.

There appears to be an inverse relationship between the use of oral contraceptives and risk of ovarian cancer, even after controlling for parity. Women with tubal ligation or hysterectomy (without oophorectomy) may also have lower risk.

Prevention:

At present time, most risk factors for ovarian cancer are not well enough understood so that primary prevention approaches can be considered. Although screening approaches have been proposed, including ultrasound and serum CA125, their benefits for population screening have not been demonstrated.

References:

1. Weiss NS, Cook,LS, Farrow DC, Rosenblatt KA. Ovarian cancer. In Schottenfeld D, Fraumeni JF Jr. (Eds) Cancer Epidemiology and Prevention 2^nd Ed. 1996. Oxford University Press, Oxford. Pp1040-1057.
2. Kelsey JL, Whittemore AS. Epidemiology and primary prevention of cancers of the breast, endometrium and ovary: a brief overview. Ann Epidemiol 1994;4:89-95.

Screening/ Early Detection

As yet there is no effective screening program. The studies performed using a combination of pelvic examination, CA125 and ultrasound have found an unacceptably high rate of false positives.