Ovarian Cancer Risk Factors


It remains unknown why one woman develops ovarian cancer while another woman does not. Research has shown that certain risk factors increase the likelihood a woman may get ovarian cancer. Other factors may actually decrease a woman’s probability of getting the disease.Having risk factors does not predict you will get ovarian cancer. Some women who get the disease have no known risk factors, and most women with the risk factors will not get ovarian cancer. However, if you think you may be at risk for ovarian cancer, you should speak with your doctor.

Factors that may increase the risk of ovarian cancer:

  • Family history of cancer:Women with a grandmother, mother, daughter or sister with ovarian cancer are at higher risk for the disease. Women with a family history of cancer of the breast, uterus, colon or rectum may also have an increased risk of the disease.
  • Strong family history of cancer of the ovary or breast: Several women in a family having ovarian or breast cancer, especially if it occurs at a young age, is deemed a strong family history for cancer. In such cases, a doctor may recommend a genetic test that can show the presence of specific gene changes or mutations in genes called BRCA1 or BRCA2 genes. Having these changes in the genes greatly increase the risk ovarian cancer and breast cancer. Approximately 10-15 percent of epithelial ovarian cancers are caused by the inheritance of mutations in BRCA1, BRCA2 and a few other identified genes (including MLH1, MSH2, or MSH6, called Lynch Syndrome) . What is responsible for the remaining 90 percent of ovarian cancer is unknown. OCRF supports research to find out why cancer occurs in certain women and not others.
  • Personal history of cancer or endometriosis: Women who have had cancer of the breast, uterus, colon or rectum have a higher risk of ovarian cancer. Having endometriosis increases the risk of clear cell and endometrioid ovarian cancers by 2-3 fold
  • Age over 55: Most women are over age 55 when diagnosed with ovarian cancer
  • No pregnancies: Older women who have never been pregnant are at increased risk
  • Menopausal hormone therapy: Women who take estrogen by itself, without progesterone, for 10 years or more may have an increased risk of ovarian cancer, studies suggest.

Factors that may decrease the risk of ovarian cancer:

  • Oral contraceptive use: Use of oral contraceptives for 5 or more years can reduce risk by approximately 50 percent or more.
  • Pregnancy: Multiple pregnancies or having first full-term pregnancy before the age of 25 decreases risk.
  • Breast feeding reduces the risk of ovarian cancer.
  • Hysterectomy/Tubal Ligation: Having a hysterectomy, or removal of the uterus while leaving the ovaries, may decrease the risk of ovarian cancer by 33 percent, according to the American Cancer Society. Having fallopian tubes tied (tubal ligation) may reduce risk by up to 67 percent, the American Cancer Society says, though researchers aren’t sure why this is the case.
  • Removal of the ovaries and fallopian tubes, or salpingo-oophorectomy, dramatically reduces the risk of ovarian cancer. Primary peritoneal cancer, which is microscopically almost identical to ovarian cancer, can still occur, but is infrequent. Women who test positive for the mutations in the BRCA1 or BRCA2 genes often elect to have prophylactic oophorectomy–removal of the ovaries–to considerably reduce their risk of ovarian cancer and potentially of breast cancer.

More information about understanding your risk of ovarian cancer is available here.

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