What Causes Ovarian Cancer?

Several subtypes of ovarian cancer exist. They’re based on the cells they arise from:

• Epithelial tumors form in a layer of tissue outside of your ovaries. According to the Mayo Clinic, they make up about 90 percent of ovarian cancers.
• Stromal tumors form in hormone-producing cells in your ovaries. About 7 percent of ovarian cancers are stromal tumors.
• Germ cell tumors form in ovarian cells that produce eggs. This rare type of ovarian cancer is usually diagnosed in younger women.

Your chance of developing ovarian cancer may be higher if you have a family history of:

• ovarian cancer
• breast cancer
• uterine cancer
• colorectal cancer

If you have a mother, sister, or daughter who’s had ovarian or breast cancer, you may have a high-risk mutation like BRCA. Men can also carry BRCA mutations, so your risk can also be tied to your father’s side of the family.

According to the ACS, about 5 to 10 percent of ovarian cancers result from inherited genetic mutations. Mutations in the BRCA1 and BRCA2 genes are linked to ovarian cancer, as well as:

• breast cancer
• primary peritoneal cancer
• fallopian tube cancer
• pancreatic cancer
• prostate cancer

If you have a BRCA1 mutation, your lifetime risk of developing ovarian cancer is 35 to 70 percent. If you have a BRCA2 mutation, your risk of developing ovarian cancer by age 70 is 10 to 30 percent.

Genetic mutations on the following genes can also increase your risk of ovarian cancer:

• PTEN
• MLH1, MLH3
• MSH2, MSH6
• TGFBR2
• PMS1, PMS2
• STK11
• MUTYH

You can’t do anything to change your genetic risk. If you have a family history of ovarian cancer, discuss the need for genetic testing with your doctor. According to the Ovarian Cancer National Alliance, all women diagnosed with ovarian cancer, primary peritoneal, or fallopian tube cancer should be referred for genetic counseling and consideration of genetic testing.

Your personal medical history also plays a role in your level of risk. Having a personal history of breast cancer may increase your risk even if you don’t have the BRCA mutation. If you also have a family history of breast cancer, your risk may be even higher. This may suggest the presence of hereditary breast and ovarian cancer syndrome, which is linked to the BRCA mutation.

Other conditions may be linked high-risk mutations or increase your risk of ovarian cancer, including:

• polycystic ovary syndrome, which is an endocrine system disorder
• endometriosis, which is a disease in which cells that line your uterus grow elsewhere
• hereditary nonpolyposis colon cancer, which is caused by many of the same genetic mutations that can increase your risk of ovarian cancer
• PTEN tumor hamartoma syndrome, which is a group of disorders that result from a mutation in the PTEN gene
• Peutz-Jeghers syndrome, which is caused by mutations in the STK11 gene
• MUTYH-associated polyposis, which is caused by mutations in the MUTYH gene

Tell your doctor if you’ve previously been diagnosed with any of these conditions.

According to the National Cancer Institute (NCI), using birth control pills lowers your risk of ovarian cancer. The longer you use birth control pills, the lower your risk may be. The protection it offers may last as long as 30 years after you stop taking the pill. Getting your tubes tied also lowers your risk of this type of cancer. Breast-feeding may also lower your risk of ovarian cancer.

On the other hand, taking fertility drugs may increase your risk of developing ovarian tumors with “low malignant potential,” warns the NCI. These tumors are made up of abnormal cells that can potentially become cancerous. The chances of this happening, however, are low.

According to the Ovarian Cancer National Alliance, you may also be at higher risk of ovarian cancer if you:

• started having periods before age 12
• gave birth to your first child after age 30
• haven’t given birth
• didn’t go through menopause until after age 50
• have taken hormonal replacement therapy to treat menopause

Your risk of ovarian cancer increases with age. You’re more likely to develop ovarian cancer after menopause. In fact, the ACS reports that half of all diagnoses occur in women age 63 or older. In contrast, ovarian cancer is quite rare in women under age 40.

In the United States, non-Hispanic white women have the highest risk of ovarian cancer, reports the Centers for Disease Control and Prevention. Hispanic women have the next highest risk. They’re followed by black women, Asian and Pacific Islander women, and American Indian and Alaskan Native women.

The relationship between ovarian cancer and diet is unclear. But having a body mass index of 30 or higher increases your risk. Adolescent obesity is also linked to higher risk, warns the NCI. Women who are 5 feet 8 inches or taller may also be at slightly higher risk of ovarian cancer.

Some risk factors for ovarian cancer are beyond your control, including your genetics, ethnicity, and age.

Other risk factors can be influenced by lifestyle changes. Do the following to lower your risk of ovarian cancer:

• Talk to your doctor about the potential benefits and risks of birth control pills.
• Eat a well-balanced diet.
• Get regular exercise.
• Maintain a healthy weight.

Talk to your doctor about your family history, personal medical history, and lifestyle habits. They can help you assess your risk of developing ovarian cancer. They may also recommend strategies to help lower your risk and increase your chances of enjoying a long and healthy life.