Doctor, what are the risk factors for ovarian cancer and what are the latest recommendations for screening?

It is estimated that in the United States, 22,430 new cases of ovarian cancer will be diagnosed every year and 15,280 women will die as a result of the disease. The lifetime risk of ovarian cancer, if a woman reaches 90 years of age, is 1 per 70; for breast cancer it is 1 out of 8. This relatively low risk of death from breast cancer compared to ovarian cancer is attributed to early diagnoses with the help of mammography and improved modalities of treatment available for breast cancer. Sadly, this has not been the case for ovarian cancer because it is often diagnosed too late.

Age is the most important risk factor. Ovarian cancers are rare before the age of 40 and peak at the ages of 65 to 75. Another risk factor is uninterrupted ovulatory cycles. This means the more you allow the ovary to function, the greater the risk of ovarian cancer. Pregnancy, lactation and birth control pills all stop ovulation and decrease the risk of ovarian cancer.

Family history of ovarian cancer is also important. The lifetime risk of ovarian cancer is approximately 5 percent for a woman with one first-degree relative with ovarian cancer and 7 percent in women with two or more relatives with ovarian cancer. Three familial ovarian cancer syndromes have been discovered, but those are beyond the scope of this article.

We have two main modalities to screen for ovarian cancer: vaginal sonography and serum Ca125.

Vaginal sonography is used to diagnose an ovarian mass. If there is suspicion of cancer, we need to remove the ovary and send it to pathology. This will result in 10 invasive surgeries (e.g. removal of the ovary) to diagnose one early ovarian cancer.

Serum Ca125 is a glycoprotein recognized by monoclonal antibodies. It is present in high concentrations on the surface of an ovarian tumor. Ca125 is elevated in 80 percent of all patients with advanced ovarian cancer, allowing a diagnosis in a later stage and only 25 to 50 percent of the time in early stages of ovarian cancer. Ca125 has been shown to increase in non-gynecological cancers, such as pancreatic, colon and lung cancer. More importantly, Ca125 can be increased in many benign conditions including fibroid tumors, endometriosis, pelvic infection, ascites of any etiology, inflammatory conditions (such as lupus) and inflammatory bowel disease (including diverticulitis).

This knowledge led the U.S. Preventive Service Task Force to conclude that the potential harm of screening for ovarian cancer outweighs the potential benefit because of the low prevalence of ovarian cancer and the invasive nature of the diagnostic testing. In breast cancer, we use mostly needle biopsies and ultrasounds. However, in ovarian cancer, we need to remove the entire ovary. The new trend has shifted from screening asymptomatic women to early diagnosis using a thorough history to identify women with symptoms significantly associated with ovarian cancer.

The four symptoms are pelvic pain, abdominal pain, increased abdominal size and abdominal bloating.

Any of the four symptoms occurring at least 12 days of a month for less than one year (e.g. recent onset) should prompt the physician to perform a good physical exam, ordering Ca125 and vaginal sonography. Two additional symptoms have been described: rapid feeling of fullness when eating and difficulty eating for prolonged periods of time. It is obvious from this discussion that recognizing early symptoms of the disease is better than random screening of the population.