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Ovarian Cancer - Risk Factors

The following have been identified as factors that increase a woman’s risk of developing ovarian cancer. While women with one or more of these risk factors have a higher-than-average chance of developing ovarian cancer, the majority of these women will never develop the disease. Conversely, many women who develop ovarian cancer have no known risk factors for the disease. It is important that women know the risk factors and symptoms of ovarian cancer to help increase the chance that it will be detected early.

Risk factors that can not be controlled

Age: The risk of ovarian cancer increases with age. The majority of ovarian cancer diagnoses occur in women who have already reached menopause. According to the National Cancer Institute, the highest incidence of ovarian cancer occurs in women over age 60. However, ovarian cancer can also affect younger women.

Family history of ovarian cancer: Women who have a family history of ovarian cancer are at higher risk of developing the disease than those with no family history. The risk is higher if a woman’s close relatives (mother or sisters) have been diagnosed with ovarian cancer (the risk is 5% over a lifetime compared with a 1.5% risk if no relatives have been diagnosed with ovarian cancer).

Genetics: BRCA1 (breast cancer gene 1) and BRCA2 (breast cancer gene 2) are two genes that, when functioning normally, help repair damage to DNA (a process that also prevents cancer development). However, women who carry mutations of BRCA1 or BRCA2 are at higher risk of developing both ovarian and breast cancer compared to women who do not have these genetic mutations.

Approximately 9% of ovarian cancer cases are due to a genetic mutation of BRCA1 or BRCA2. The American Cancer Society estimates that between 56% and 87% of women with inherited BRCA1 or BRCA2 mutations will develop breast cancer by age 70. The lifetime ovarian cancer risk for women with BRCA1 or BRCA2 mutations is estimated to be between 17% and 44%. Women with a strong family history of ovarian or breast cancer may wish to talk to their physicians about undergoing genetic testing to determine whether they carry the BRCA gene mutations. Learn more about genetic testing.

Hereditary nonpolyposis colon cancer (HNPCC): Women with HNPCC are also at slightly higher risk of developing ovarian cancer. HNPCC is a condition caused by inherited genes and usually develops in younger women (under 40) with a strong family history of HNPCC. In addition to an increased risk of ovarian cancer, HNPCC puts women at very high risk of colon cancer and endometrial cancer (cancer of the uterine lining).

Early menstruation/late menopause: Women who begin menstruating before age 12 or those who do not reach menopause until after age 50 are at an increased risk for ovarian cancer as well as breast cancer. This may be because women who have more menstrual cycles throughout their lifetime are at higher risk of ovarian and breast cancer. Research suggests that women who become pregnant, breast-feed, or take birth control pills are at a lower risk of developing ovarian cancer.

Personal/family history of breast cancer: Women who have been diagnosed with breast cancer have an increased risk of developing ovarian cancer because many of the risk factors for breast cancer (including early menstruation, late menopause, delayed childbirth, BRCA gene mutations, etc.) also put women at risk for ovarian cancer.

The majority of women who develop ovarian cancer have no known risk factors. Also, many women who have some of the risk factors for ovarian cancer never develop the disease.