Ovarian cancer is not a common form of cancer. However, it can be a lethal one. It accounts for only 4% of all cancers in women, but it’s the fifth leading cause of cancer death.
The ovaries are almond-sized structures that reside deep in the pelvis. They are responsible for producing estrogen and progesterone during a woman’s monthly cycle. Ovaries are susceptible to both benign and malignant (cancerous) tumors, and due to their small structure and location deep in the pelvis, malignant tumors commonly go undetected until they have spread throughout the abdomen.
The majority of ovarian cancers arise from the surface of the ovary; this is called epithelial ovarian cancer. Malignant tumors can also arise from the connective tissue of the ovaries, as well as the germ cells or eggs. Currently there are no good screening tests for ovarian cancer, like a mammogram for breast cancer or a Pap smear for cervical cancer.
There are, however, subtle warning signs and symptoms of the illness. But recognizing if you are at elevated risk to develop ovarian cancer may allow you to take a proactive approach to your medical care in order to prevent the disease.
Overall, 1 in 70 women in the United States will develop ovarian cancer, for a 1.6% lifetime risk of developing the disease. Some women may be at a higher risk based on age, personal medical history, and family history.
The greatest risk factor for ovarian cancer is age.
All cancers result from accumulated mutations in genes important for cell growth. These mutations may be inherited from our parents, but they also can result from environmental exposures. The longer we’re alive, the more gene mutations accumulate in our cells, and the more at risk we are for developing a cancer.
The average age for a woman to develop ovarian cancer is 63 years old, although some women with genetic or hereditary risk factors will develop the disease at a younger average age of 54.
Other than age, family history is the most important identifiable risk factor.
If your family has multiple cases of breast or ovarian cancer, you may be at elevated risk.
Currently there are three genetic syndromes that are associated with a significant increased risk for ovarian cancer:
- Hereditary breast and ovarian cancer. In this syndrome, breast and/or ovarian cancer are found in each generation, usually due to mutations in BRCA1 and BRCA2 genes.
- Hereditary site-specific ovarian cancer. In this syndrome, ovarian cancer is found in multiple relatives, again usually due to mutations in a BRCA1 or BRCA2 genes.
- Ovarian cancers associated with colon and endometrial cancers. This is also known as hereditary non polyposis colorectal cancer syndrome – HNPCC.
Women who inherit a BRCA1 or 2 mutation may have an up to 44% chance of developing ovarian cancer, and up to 90% chance of developing breast cancer.
Women who inherent a mutation in an HNPCC gene have an up to 10% risk of developing ovarian cancer, 60% chance of developing uterine cancer, and an 80% chance of developing colon cancer.
The risk of ovarian cancer is linked to the number of menstrual cycles that a woman has in her lifetime. This is thought to be linked to ovulation.
Women who get their periods early, enter menopause at a late age, do not have children, or do not breast feed have an elevated risk of developing ovarian cancer.
Maneuvers that decrease the number of ovulations in a woman’s lifetime, such as using oral contraceptives, lead to a decreased risk of developing the disease. Hormone replacement therapy with postmenopausal estrogen use, and a personal history of endometriosis may be associated with an elevated risk of developing ovarian cancer. So does a personal history of breast cancer.
All women should be aware of the early signs and symptoms of the disease (see my recent post on this topic), and should see their gynecologist on yearly basis. All women should carefully review their risk of ovarian cancer with their health care professional.
For some women, a complete family history analysis with a health care professional specializing in genetics, or more intensive surveillance, may be recommended. Women who may be at a significantly elevated risk to develop the disease include those with:
- Close personal family history of ovarian cancer (mother, sister, daughter, aunt)
- Personal history of breast cancer
- Close family member with breast cancer before the age of 50
- Close family member with uterine cancer before the age of 50, or multiple family members with uterine cancer
- Close family member with colon cancer before the age of 50, or multiple family members with colon cancer
- Family member who has tested positive for a BRCA1, BRCA2 or HNPCC (MLH1, MSH2 or MSH6 genes) gene mutation
Women who have any of these characteristics should carefully review their personal and family histories with a health care professional knowledgeable in cancer genetics.
It is important that you review three generations of family history, with the understanding that genes responsible for women’s cancer can travel down your father’s side of the family, too.
For some women, genetic counseling may be recommended to further determine actual risk for developing a malignancy. Some women may be recommended to undergo more intensive surveillance for ovarian cancer, including a pelvic examination every six months, with a transvaginal ultrasound and CA125 blood test.
For some women, more intensive breast surveillance—with additional tests such as a breast MRI—may be recommended. Others may be recommended to undergo colonoscopies at an earlier age, or more frequently, than average. For women at the highest risk, prophylactic removal of the ovaries and breasts may also be considered.
The take-home message: know your family history of cancer and review it carefully with your health care professional. If you think that you may be at elevated risk to develop ovarian cancer, bring this to the attention of your personal physician.
A member of the Women's Voices for Change (WVFC) Medical Advisory Board, Dr. Elizabeth Poynor is a practicing gynecologic oncologist and pelvic surgeon, with a Ph.D. in cell biology and genetics. Her private practice in New York focuses on cancer diagnosis, prevention and treatment. Dr Poynor is also a contributor to WVFC.