Each year, about 22,000 women in the United States are diagnosed with ovarian cancer. While it is the ninth most common cancer (other than skin cancer) in women, ovarian cancer ranks fifth in cancer deaths among women. Most women who develop ovarian cancer are over the age of 60, and it is found more often in white women than in African-American women.
Ovarian cancer starts in the ovaries, which are part of a woman’s reproductive system. One ovary is on each side of the uterus (womb). They are oval and produce eggs (ova) that travel through the Fallopian tubes to the uterus. The eggs may be fertilized by sperm and grow into a fetus. Ovaries also make the hormones estrogen and progesterone.
Over the past 20 years, the five-year survival rate for ovarian cancer has improved steadily. Progress continues to be made, and MD Anderson is leading research into early detection, prevention and treatment.
Ovarian Cancer Types
Some tumors found in the ovaries are benign (not cancer) and do not spread beyond the ovary. Others are malignant (cancer) and can spread to other parts of the body.
There are many types of ovarian cancer. Some types of ovarian cancer are extremely rare and require specialized treatment.
The main types, which are listed below, are named for the cells where they start.
Epithelial: About 90% of ovarian cancers start in the epithelium tissue, which is the lining on the outside of the ovary. This type of ovarian cancer is divided into serous, mucinous, endometrioid, clear cell, transitional and undifferentiated types. The risk of epithelial ovarian cancer increases with age, especially after the age of 50.
Germ cell: Germ cell tumors account for about 5% of ovarian cancers. They begin in the egg-producing cells. This type of ovarian cancer can occur in women of any age, but about 80% are found in women under the age of 30. The main subtypes are teratoma, dysgerminoma, endodermal sinus tumor and choriocarcinoma.
Sex cord stromal: These tumors, about 5% of ovarian cancers, grow in the connective tissue that holds the ovary together and makes estrogen and progesterone. Most are found in older women, but sometimes they occur in girls.
Sex cord stromal tumors usually do not spread as fast as other ovarian tumors. Sub-types include granulosa, granulosa-theca and Sertoli-Leydig cell tumors.
Primary peritoneal cancer is a rare cancer. It has cells like those on the outside of the ovaries, but it starts in the lining of the pelvis and abdomen. Women can get this type of cancer even after their ovaries have been removed. Symptoms and treatment are similar to epithelial ovarian cancer. Fallopian tube cancer is also a rare cancer. It starts in the fallopian tube and acts like epithelial ovarian cancer. Symptoms and treatment are similar to ovarian cancer.
Ovarian Cancer Risk Factors
Anything that increases your chance of getting ovarian cancer is a risk factor. These include:
- Age: The risk of ovarian cancer increases with age. About half of ovarian cancers are in women over 60.
- Family history of ovarian cancer
- Genetic factors: Approximately 10% to 15% of ovarian cancers are due to genes that make you more likely to develop cancer.
- Never having children. The more children you have, the less likely you are to develop ovarian cancer.
Not everyone with risk factors gets ovarian cancer. However, if you have risk factors, it’s a good idea to discuss them with your health care provider.
Ovarian Cancer Screening
While no standardized screening tests have been shown to improve ovarian cancer outcomes, MD Anderson is working to change that. CA-125, a cancer biomarker being studied at MD Anderson, as well as other new biomarkers, are being evaluated as a screening test.
MD Anderson recommends that women who are at high risk for ovarian cancer be screened regularly. You are considered high risk if you have:
- BRCA1 or BRCA2 gene
- Hereditary breast ovarian cancer syndrome
- Hereditary non-polyposis colorectal cancer (HNPCC), also called Lynch syndrome
- BRIP1, RAP51C, or RAD51D gene
Some people have an elevated risk of developing ovarian cancer. Review the ovarian cancer screening guidelines to see if you need to be tested.
Some cases of ovarian cancer can be passed down from one generation to the next. Genetic counseling may be right for you. Learn more about the risk to you and your family on our genetic testing page.