Ovarian cancer is the leading cause of U.S. gynecologic cancer deaths, even though the disease accounts for only about 3 percent of all cancers in women. More than 22,000 women are diagnosed with ovarian cancer each year in the United States: about 15,500 die of the disease each year, according to the National Cancer Institute.
One reason for the high death rate is that ovarian cancers usually are not detected until they are at an advanced stage and have spread beyond the ovaries. This is because early symptoms are usually mild and difficult to detect.
Most ovarian cancers are either epithelial carcinomas—lesions that begin in the cells on the surface of the ovary—or malignant germ cell tumors that begin within the cells of the ova, or eggs, inside the ovary.
The average woman’s chance of developing ovarian cancer during her lifetime is about 1 in 71 and about 1 in 95 of dying from the disease. But some women are at higher risk. Known risk factors for ovarian cancer include:
The incidence of ovarian cancer increases with age, especially after menopause. In fact, half of all cases are detected in women age 65 or older, and most are diagnosed after age 60.
The presence of an ovarian mass or cyst in a post-menopausal woman should generally be evaluated with surgery, especially if her blood levels of the cancer antigen 125 (CA125) are elevated.
Ovarian cancer rates are highest in developed countries where diets are rich in fat content.
Saturated fats (the kind found in red meats, whole milk and cheese) are most often linked to ovarian cancer, although a causal relationship has been difficult to establish.
Women who have never been pregnant or have had problems with fertility are at an increased risk of ovarian cancer.
Fertility drugs such as clomiphene citrate and pergonal have been implicated as causing ovarian cancer, but more recent research suggests that while the use of these drugs is associated with both infertility and ovarian cancer, they do not cause ovarian cancer.
Ovarian cancer is also more common in women who began menstruating before age 12 or who reach menopause after age 50.
Women who take birth control pills are at lower risk for ovarian cancer. The longer a woman is on the pill, the lower the risk. Five years of birth control pill use reduces the risk of ovarian cancer by about 50 percent.
Tubal ligation has a similar protective effect against ovarian cancer, although the mechanism for this is unknown.
The incidence of ovarian cancer is highest among white women in Europe and North America and lowest among black women, regardless of their location.
The incidence of ovarian cancer is also low among Asian women.
Women with a strong family history of ovarian cancer or breast cancer appearing before age 50 have an increased risk of Breast and Ovarian Cancer Family Syndrome.
Having one first-degree relative (a mother, daughter or sister) with the disease increases the risk of ovarian cancer threefold. The more relatives who have had the disease, the greater a woman’s risk.
Experts attribute the majority of familial ovarian cancer to genetic mutations in the BRCA1 and BRCA2 genes, which normally help protect against both breast and ovarian cancer. Women who inherit mutations in BRCA1 have a 40 percent to 50 percent lifetime risk of developing ovarian cancer and an almost 80 percent chance of developing breast cancer. A mutation in the BRCA2 gene results in a 20 percent lifetime risk of ovarian cancer.
Less commonly, a mutation in the HNPCC gene that normally protects against a type of colon cancer (called hereditary nonpolyposis colon cancer) also raises the risk of ovarian cancer, but to a lesser degree than mutations in BRCA1 and BRCA2. Families carrying these genes come from all backgrounds but the mutation rate is highest among those of Ashkenazi Jewish descent (whose ancestors came from eastern and central Europe), with 2 percent of the population carrying mutations in either BRCA1 or BRCA2.
Genetic testing is available to determine if a woman is at increased genetic risk of developing ovarian cancer. Women known to be at high risk for ovarian cancer may be good candidates for prophylactic (preventative) removal of their fallopian tubes and ovaries. Prophylactic surgery almost always can be performed using a minimally invasive approach.
Among ovarian cancer patients who underwent complex surgical and medical procedures, numerous studies suggest when care was delivered by gynecologic oncology specialists at high volume centers had improved clinical and economic outcomes. Despite such data, the majority of ovarian cancer care in the United States remains decentralized.
At the Ovarian Cancer Center, we provide patient-centered care from a multidisciplinary team of specialists, including gynecologic oncologists, pathologists and oncologists.
For more information or to make an appointment, please call 714.456.8000 or email us at ovariancancer@uci.edu.