Understanding Ovarian Cancer -- the Basics
What Is Ovarian Cancer?
Flanking the uterus are the two ovaries, each about the size of an almond, which produce eggs and female hormones. Ovarian cancer can occur at any age, even in childhood, but is most common after menopause. The disease accounts for about 22,000 new cases and almost 15,000 deaths annually in the U.S.
During her childbearing years, a woman's ovaries deliver eggs to the uterus through the fallopian tubes. The ovaries are susceptible to several types of growths, which are often benign cysts, but are sometimes cancerous. The cancer typically has no obvious symptoms until it is well advanced. Early growths can sometimes be detected during a routine pelvic exam.
If ovarian cancer could be readily diagnosed in its earliest stages, more women would be cured. But like many cancers, it usually has spread by the time it is diagnosed. The importance of early diagnosis is clear: About 90% of women live 5 years or more if ovarian cancer is detected early; the rate for all cases is only about 40%. Unfortunately only 15% of ovarian cancers are found at an early stage.
What Causes Ovarian Cancer?
Most women with ovarian cancer have no family history of the disease, yet a woman is more likely to get the disease if her mother or sister has had ovarian, breast, or uterine cancer; the more relatives affected, the greater the risk. Some women have an inherited gene mutation, such as BRCA, which puts them at significant risk for ovarian cancer. Women who have had few or no children, who delay childbearing until their 30s, or who have trouble conceiving, are also at greater risk for ovarian cancer. There is a link between the number of periods in a women’s life and her risk of ovarian cancer.
Some studies have also reported that long-term use of the fertility drug clomiphene citrate, especially if no pregnancy took place, may increase the risk of borderline ovarian tumors. This finding is not clear, because infertility itself is a risk factor of developing ovarian cancer. Those who have several children, who breastfeed their infants, or use birth control pills, or have a tubal ligation are at reduced risk. The difference may be linked to less frequent ovulation.
Most ovarian cancers occur after menopause, between the ages of 50 and 75. The peak incidence of ovarian cancer is between the ages of 75 and 79, so its incidence clearly increases with age.
A study from the American Cancer Society has found that the risk of death from ovarian cancer is higher in overweight women. Evidence suggests that following a low-fat diet may lower risk for ovarian cancer.
Using postmenopausal hormones for more than 10 years may also slightly increase ovarian cancer risks. However, the data are inconsistent, so it is important to discuss these risks with your health care provider.