Ovarian cancer is often called the silent killer because there is no good equivalent screening tool. For the last twenty years, doctors have known that a protein called CA-125, is much more prevalent in ovarian cancer cells than healthy cells. A blood test that looks for CA-125 is used to determine whether an ovarian cancer patient's treatment is working. However, the CA-125 test hasn't been an effective screening tool for ovarian cancer because many women who have high levels of this protein don't actually have cancer.
For eight years, researchers followed over 3,200 postmenopausal women age 50 and older who didn't have a family history of the disease. They started by testing the women's CA-125 levels. Based on the woman's age and depending on how high those levels were, the women were asked to get their next blood test one year later, to wait three months, or If their levels were high, they were immediately referred to ultrasound screening and a surgeon.
Using criteria developed by the researchers, 82 percent of the women had low CA-125 levels and were told to come back in a year. They were classified as low risk.
Over the course of the study, about 7 percent of the women were judged to be at intermediate risk based on their protein levels and were asked to get tested every three months. And less than 1 percent were at high risk and sent to get an ultrasound and see a surgeon immediately.
Five women were found to have ovarian cancer, all at an early stage. The study provides early evidence that this new method of using the CA-125 test could be a feasible strategy for screening women over 50 years of age.
Because ovarian cancer is so rare, a much larger trial is needed. Ovarian cancer strikes one in 2,500 post-menopausal women – and one in 10,000 women between the ages of 35 and 50.
This does not mean that all women at the age of 50 should be tested for C-125. Women with unidentified symptoms or a family history should be tested.