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Types of Cancer > Gynecologic Cancers > Ovarian Cancer > Overview
Ovarian Cancer: The Basics
Christopher Dolinsky, MD and Carolyn Vachani, MSN, RN, AOCN
Affiliation:
Abramson Cancer Center of the University of Pennsylvania
Last Modified: March 6, 2008
How can I prevent ovarian cancer?
Unfortunately, there aren't very good screening methods for ovarian cancer, so preventing it is a particularly important challenge. If you are a woman without a family history/genetic syndrome, then the best way to prevent ovarian cancer is to alter whatever risk factors you have control over. Consider using methods of birth control (like oral contraceptive pills, or Depo-Provera) that stop ovulation/menstruation or think about tubal ligation/hysterectomy for permanent sterilization when the time is right. If you plan to get pregnant, try and do so before age 30 and consider breastfeeding.
Women who are carriers of one of the above mentioned genetic syndromes face different decisions. They generally need to have more rigorous screening done for ovarian cancer, they may want to take a drug, such as tamoxifen, to reduce their risk, and some may elect to have their ovaries removed when they are still healthy (called a prophylactic oophorectomy). This should only be done when a woman is finished having children, and it can drastically reduce a woman's chances for developing ovarian cancer (but not reduce the risk to zero). Before a woman decides to do this, she should have genetic testing and a significant amount of counseling from a physician who has experience with genetic diseases.
While a diet high in animal fats has been implicated in ovarian cancer, a diet rich in fruits and vegetables may have a small preventive effect. It has been suggested that supplementation with vitamins A, C, and E may decrease your risk, but further studies need to be performed before any nutritional recommendations can be made regarding ovarian cancer prevention.
What screening tests are available?
An ideal screening test for ovarian cancer could save many lives. The vast majority of ovarian cancers are found at advanced stages, because early, small ovarian cancers are asymptomatic or have vague symptoms and cannot usually be found by a physician's exam. Patients who are diagnosed with early ovarian cancers tend to respond to treatment better than patients with more advanced cancers. Currently, there are not any effective approaches to ovarian cancer screening. There are a few tests that are being studied, but we need further data before they become routine for ovarian cancer screening.
Right now, the only screening that is recommended for the general population (women without hereditary cancer syndromes) is an annual pelvic examination. Your physician can usually feel your ovaries during the bi-manual portion of the exam, and if any abnormalities are felt, you can be referred for further tests. The major limitation to this method is that early ovarian cancers aren't usually appreciated on examination, and are often missed.
There are a few other tests that are currently being studied for ovarian cancer screening. One is a blood test that looks for a protein named CA-125. CA-125 is a protein that is shed from damaged ovary cells, and is often elevated in ovarian cancer. There are a few problems with CA-125 as a screening test. It is elevated in many other diseases and conditions besides ovarian cancer, including other cancers, endometriosis, fibroids, menstruation, colitis, diverticulitis, pancreatitis, lupus, and inflammation of the lining of the lung or heart. Only 50% of early stage ovarian cancers cause an elevated CA125, and nonepithelial ovarian tumors do not produce CA125.
One possible way to use CA-125 for ovarian cancer screening is to check it and then re-check it 6 months later. If it drastically increases over this time, then it is more suggestive of ovarian cancer. The concern is that many patients without ovarian cancer will have elevated CA-125 levels and end up getting unnecessary further workup (which often means going for needless surgery). It can be dangerous to perform surgery unnecessarily, so we need a test that is more specific for ovarian cancer before it can be recommended for screening the general population.
Another investigational method for ovarian cancer screening is transvaginal ultrasonography. Ultrasound is an imaging technique that uses sound waves that bounce off of tissues and provide a picture of whatever is being investigated. By inserting an ultrasound probe into a woman's vagina, doctors can get a relatively good look at her ovaries. If the ovaries look suspicious, then further tests can be done. The biggest problem with using transvaginal ultrasound for ovarian cancer screening is the same problem as using CA-125; both tests cause too many healthy women to require unnecessary procedures because the tests are not specific enough for ovarian cancer. Doctors hope that perhaps a combination of CA-125 and transvaginal ultrasound will be an effective method for ovarian cancer screening, and large studies are currently underway examining the feasibility and usefulness of this approach. This will involve combining the two studies, followed by an algorithm of pathways defining what results need to be followed up with a surgical procedure.
Early results from one of these large studies (United States National Institute of Health Prostate, Lung, Colorectal and Ovary Study) that combined both tests found that in the 571 women who required a surgical procedure as follow up to screening, only 18 cancers were found. This is not acceptable for a general screening test, but this may improve as the trial goes on, as many of the false results were preexisting conditions that were found on initial screening. The second large, ongoing study is the UK Collaborative Trial of Ovarian Cancer Screening.
A urine screening test that identifies levels of a protein called Bcl-2 is in early clinical trials. Researchers have found that this protein was 10 times higher in women with ovarian cancer when compared to healthy individuals and those with benign ovarian disease. In early studies, the test detected 92% of ovarian cancers.
Currently, the general population should only be screened for ovarian cancer with a pelvic examination. However, women with a strong family history or those with a proven hereditary cancer syndrome may need to get more rigorous screening with serial CA-125 tests and/or transvaginal ultrasounds. Talk to your doctor about your ovarian cancer risk, and what the best way to go about screening is in your particular case.
What are the signs of ovarian cancer?
For many years, ovarian cancer has been called a “silent killer” because it was thought that symptoms did not develop until the disease was advanced. Recently, ovarian cancer experts found that this was not true, and most women had symptoms early on that were dismissed by themselves or their healthcare providers. Experts collaborated to develop the Ovarian Cancer Symptoms Consensus Statement, which describes important symptoms.
The symptoms that are more likely seen in women with ovarian cancer than healthy women include:
- Bloating
- Pelvic or abdominal pain
- Difficulty eating or feeling full quickly
- Urinary symptoms (urgency or frequency)
While these symptoms can be caused by other issues, women with ovarian cancer report that the symptoms persist and represent a change from their normal. The frequency and number of these symptoms are also key factors in the diagnosis.
Women who experience these symptoms almost daily for more than a few weeks should see a healthcare provider (preferably a gynecologist) for evaluation.