Ovaries are the organs on either side of the uterus that produce eggs and female hormones, and regulate the menstrual cycle. Ovarian cancer occurs when cells begin dividing abnormally, and invade surrounding organs and spread or metastasize throughout the body.
Ovarian cancer, if caught early, has an excellent cure rate. Patients whose ovarian cancer has not spread beyond the ovary at the time it is detected have a 90 to 95% chance of living 5 years or longer after treatment. Unfortunately ovarian cancer is very difficult to catch at this early stage, because symptoms are very subtle, and often attributed to other conditions. As a result, most ovarian cancer does not become evident until it has spread throughout other organs, and at that point, is much more difficult to cure. About 20% of ovarian cancer is detected early, and 80% at an advanced stage.
How Common is Ovarian Cancer?
About 3% of all new cancers detected in women each year are ovarian cancers. The lifetime risk of developing an ovarian cancer used to be about 1/70, and now appears to be about 1/50. It is uncommon in women under 40 years of age.
Risk Factors for Developing Ovarian Cancer
Age: Most women who develop ovarian cancer are between 50 and 75 years of age. Risk increases with age.
Ovulation: Women who ovulate less are at lower risk of ovarian cancer. For this reason, childbearing and breastfeeding appear to be protective. The oral contraceptive pill decreases the risk for ovarian cancer. Women who have either never been pregnant, or have become pregnant for the first time after age 30 are at higher risk. Late menopause, after age 52, seems to increase the risk as well.
Fertility Drugs: Use of fertility medications, especially for a cumulative period of more than a year, seems to increase risk of ovarian cancer.
Breast Cancer: A personal history of breast cancer appears to be a risk factor.
HRT Use: Use of postmenopausal equine estrogen and synthetic progestin seems to increase the risk of ovarian cancer.
Family History of Breast, Ovarian or Colon Cancer: A family history of these cancers seems to increase personal history of ovarian cancer. About 10% of ovarian cancers are genetic, possibly slightly more per some studies, and the rest are sporadic and random.
BRCA 1 or 2 gene: About 5% (some studies as much as 10%) of ovarian cancers occur in women who have inherited the BRCA 1 or 2 gene. Presence of this gene can be detected by blood test. Carrying this gene means that an individual’s risk of ovarian cancer is about 40% (range 10 to 80%, depending on the exact mutation). Genetic counseling is important if you carry the BRCA gene, since you are at risk for some other cancers as well, including breast cancer.
It is important to realize that many women with these risk factors do not develop ovarian cancer. It is also important to realize that many women who develop ovarian cancer have none of these risk factors.
Screening for Ovarian Cancer
There is unfortunately not a good screen for ovarian cancer although there has been much study in this area. CA-125 has too many false positives and false negatives to be a good screen, and is often misleading. Ultrasound would be a good screen but would cost billions if every woman ages 40 to 60 were screened annually. However if you have symptoms (see list below), which many women do, because they are vague and non-specific) then a screen is a good idea.
Symptoms
The problem with ovarian cancer is that it doesn't cause severe symptoms until it developed into an advanced stage. It does seem to cause severe symptoms at earlier stages although there may be subtle symptoms.
- bloating
- abdominal or pelvic pain
- difficulty eating or feeling full quickly
- urinary urgency and frequency
These symptoms are common, and are more significant if they are new or persistent. Other symptoms might include abnormal vaginal bleeding, fatigue, weight loss, and increase in abdominal girth, although these are later signs.
Investigations
Investigations usually start with a history and physical exam, and imaging the abdomen and pelvis, usually with pelvic ultrasound, +/- CT +/- MRI.
Treatment
Ovarian cancer must be treated surgically, usually by a subspecialist known as a "gynecologic oncologist". The cancer is staged at the time of surgery. Usually the surgery involves removing the uterus including the cervix, both ovaries, sampling lymph nodes, removing the omentum (the fatty apron that covers the bowel) and doing multiple biopsies. If the cancer is small, detected early and limited to one ovary, and further childbearing ability is desired, it is possible to just remove one ovary.
Further treatment involves chemotherapy if the cancer is advanced. Ovarian cancer is usually not treated with radiation.
Follow-up
After ovarian cancer, your disease is usually followed at regular intervals by physical exam, imaging and blood tests.
Summary
It is important to know if you are at risk for ovarian cancer. The birth control pill is often helpful in preventing ovarian cancer if you are. If you are at particularly high risk (ie carry a BRCA genetic mutation), then a surgery to remove the ovaries once childbearing is complete is sometimes recommended. Be sure to tell your provider if you have any of the signs and symptoms that might be early warning signs of ovarian cancer, such as bloating, difficulty eating, urinary urgency and frequency, or abdominal and pelvic pain.
More information is available through the ACOG Patient Brochure on Ovarian Cancer and through a very well written ACOG guide called Protect and Detect.
