Parity is an important risk factor. The risk for epithelial ovarian cancer is increased in women who have not had children and possibly those with early menarche or late menopause. Women who have been pregnant have a 50% decreased risk for ovarian cancer compared with nulliparous women. Multiple pregnancies offer an increasingly protective effect. Oral contraceptive use significantly decreases the risk for ovarian cancer.
These factors support the idea that risk for ovarian cancer is related to ovulation. Two theories regarding this relationship have been proposed. The incessant ovulation theory suggests that repeated ovarian epithelial trauma caused by follicular rupture and subsequent epithelial repair results in genetic alterations within the surface epithelium. The gonadotropin theory proposes that persistent stimulation of the ovaries by gonadotropins, coupled with local effects of endogenous hormones, increases surface epithelial proliferation and subsequent mitotic activity.
Family history plays an important role in the risk of developing ovarian cancer. The lifetime risk for developing ovarian cancer is 1.6% in the general population. This compares with a 4%-5% risk when one first-degree family member is affected, rising to 7% when two relatives are affected. Five percent to 10% of cases of ovarian cancer occur in an individual with a family history of the disease. Only a small percentage of these patients have an inherited genetic abnormality, and the risk for this occurrence increases with the strength of the family history. Hereditary epithelial ovarian cancer occurs at a younger age (approximately 10 years younger) than nonhereditary epithelial ovarian cancer, but the prognosis may be somewhat better.
For more on the etiology of ovarian cancer, read here.
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Any views expressed above are the author's own and do not necessarily reflect the views of WebMD or Medscape.
Cite this: Michel E. Rivlin. Fast Five Quiz: Ovarian Cancer - Medscape - Sep 27, 2018.
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