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Sadly, ovarian cancer is one of those diseases that we have no ability to detect early. The CA-125 blood test is vastly misunderstood. I receive at least one request a week to have the level checked. This misperception originates from the land of rampant testing for dollars to our south, and from misinformed Internet testimonials. Ovarian cancer affects 1 in 70 women, and when it does, it is often picked up at the metastatic stage when symptoms occur and survival chances drop. This is a frightening proposition for many women.
CA-125 is a protein found in some cells of the fallopian tubes, uterus, cervix, ovaries and linings of the lungs and abdomen. CA-125 levels can rise during normal menstruation, with pregnancy, endometriosis and even with lung infections. Similarly, these levels may not rise at all during the early stages of ovarian and peritoneal cancer. It has no value as a screening test for ovarian cancer, except in some family groups. However, it is used in monitoring cancer treatment. CA-125 levels are ordered when there is suspicion that an ovarian cancer might be present. These cancers are usually large enough to produce an elevated level. Other testing is still required to confirm the diagnosis. As treatment is administered, the levels are repeatedly measured as a way of determining response.
The most common type of ovarian cancer is an epithelial carcinoma which in time can cause CA-125 levels to rise. The ovaries function to produce eggs and some hormones. To accomplish this, the ovaries are programmed to continuously produce cystic type structures, which normally rupture or involute. There is increased risk for ovarian cancer in women whose close relatives had the disease. Interestingly, multiple pregnancies lower the risk as does using the birth control pill. The pill mimics a pregnancy type state to achieve its function.
As yet, there is no method to detect ovarian cancer at an early stage, unlike the Pap smear test which detects cervical cancer. There are no blood tests yet available which provide early warning signs for ovarian cancer. In Ontario, OHIP declines to cover a CA-125 test ordered for screening. There is an option of paying for it yourself, if this may ease any impending anxiety. During the annual Pap smear test, your doctor will attempt to assess the ovaries by feel. In some people this can pick up abnormalities. Ultrasound exams are commonly employed to evaluate abnormalities. A recent world congress meeting concluded that ultrasounds have no value as a screening tool for ovarian cancer. These "just-in-case" exams ordered for women with no symptoms have a high false-positive rate, and could lead to unnecessary surgery and anxiety. This doesn't offer much comfort for most women, but the best strategy so far is to pay attention to changes in your body and have them evaluated.
