Ovarian cancer is the eighth most common cancer among women (defined here as people assigned female at birth). According to the American Cancer Society, 20,890 women in the U.S. will receive a new diagnosis of ovarian cancer and 12,730 will die from it. While sobering statistics, ovarian cancer compared to breast cancer is still relatively rare in the general population. The average woman’s lifetime risk for developing ovarian cancer is less than 2% (or 1 in 90).
Despite strides made to increase awareness around the signs and symptoms of ovarian cancer, there are still no effective screening methods available for early detection. The vast majority of ovarian cancers are detected at a late stage, which leads to poorer outcomes.
Many people wonder what causes ovarian cancer, and there are several risk factors to be aware of: older age (65+), obesity, endometriosis, early menstruation, late menopause and never giving birth, among others.
Additional key risk factors include family history and/or having an inherited mutation in a gene associated with ovarian cancer, such as BRCA1 and BRCA2.
What role do genes play in cancer?
Our genes are like a set of instructions that tell our bodies how to grow and develop. Sometimes, genetic changes, or mutations, can occur in our genes. These mutations affect the genes’ ability to protect our body from diseases such as cancer. It is having a mutation in our genes (not the genes themselves) that increases the risk for cancer.
Hereditary predisposition to ovarian cancer
It is important to know that most mutations related to cancer happen at random over a person’s lifetime. Only about 5% to 10% of all cancers are associated with inherited mutations, or mutations that are passed down from a mother or father.
In regard to ovarian cancer, about 20% of cases are said to have a hereditary component. As mentioned earlier, the average lifetime risk for women to develop ovarian cancer is less than 2% (or 1 in 90). Women with inherited BRCA1 or BRCA2 mutations have risks of developing ovarian cancer up to 60% or 30%, respectively.
That’s why identifying individuals at risk for inherited mutations is critical and why understanding family history is important. Women with a family history of ovarian cancer in close blood relatives (mothers, sisters, daughters, aunts and grandmothers) may be at higher risk. Studying the family history helps identify people who could benefit from genetic testing.
Besides BRCA1/2, there are other hereditary ovarian cancer genes such as ATM, BRIP1, Lynch syndrome (MLH1, MSH2 and MSH6), PALB2, RAD51C and RAD51D. The risk of cancer for each of these genes varies, but these genes are often tested alongside BRCA1/2 when assessing inherited cancer risk.
Genetic testing and ovarian cancer
Because having a gene mutation can significantly increase a woman’s risk for ovarian cancer, identifying those who carry these mutations is important. For this reason, genetic testing has become an invaluable tool. Genetic test results provide information about cancer risks and help guide future medical management decisions.
Genetic testing can also provide information regarding risks for other cancers. Women with BRCA1 or BRCA2 mutations have an increased risk for breast and pancreatic cancer. BRCA1/2 mutations can also affect men, increasing risks for male breast cancer, prostate cancer and pancreatic cancer. Established screening and preventive guidelines exist for individuals with these mutations.
Genetic testing provides information for family members as well. If a harmful gene mutation is found, sharing this information with family members can help identify relatives who may share the same genetic risk factor.
Why perform genetic testing for ovarian cancer susceptibility?
There are several benefits to having genetic testing for ovarian cancer.
For unaffected women who have a mutation in an ovarian cancer-related gene, there are options they can consider to reduce their risk of ovarian cancer:
- Surgical: Risk-reducing salpingo-oophorectomy (a surgery to remove the ovaries and fallopian tubes). Sometimes this also includes the uterus.
- Non-surgical: Women can consider oral contraceptives (birth control) or an intrauterine device (IUD). Both methods have been shown to reduce the risk for ovarian cancer.
Each option has benefits and risks. Women should speak with a doctor before pursuing any of these methods, regardless of genetic status.
For women with ovarian cancer and BRCA mutations, there are targeted therapy options available, such as PARP inhibitors. These work by blocking the pathway cancer cells use to repair themselves and have been used in treatment for ovarian cancer patients. Research is ongoing to see if PARP inhibitors can be used in women with other gene mutations.
Next steps
If you have a personal or family history of ovarian cancer (or related cancers), you should talk to your doctor about a referral to a genetic counselor, who can assess your risk and determine whether testing is appropriate.
The Northside Hospital Cancer Institute has a dedicated team of genetic counselors trained to help individuals navigate the genetic testing process. If you have any questions about genetic counseling or testing, or would like to make an appointment, call 404-851-6284 or email genetics@northside.com.
Learn more about the Northside Hospital Cancer Institute Cancer Genetics Program.
