With good reason, ovarian cancer is the most feared gynecologic malignancy. Hardly a clinic day goes by without one of my patients asking if we've figured out how to screen for cancer of the ovary.
Most often discovered after it has spread from the ovary, ovarian cancer is the leading cause of death from gyn cancers and the fifth-leading cause of cancer deaths in women. Yet, an effective screening test for ovarian cancer, comparable to a pap smear or a mammogram, remains an elusive goal.
Why is it so hard to screen for cancer of the ovary?
The foremost reason (fortunately) is that ovarian cancer is not among the most common cancers — it affects 1.4% of US women. It is easier to develop effective screening tests for more common conditions, especially if we are trying to screen everyone potentially at risk.
Secondly, the ovaries are relatively small organs that are deep in the pelvis. Only with surgery can the ovaries be visualized directly. And, as part of their normal function prior to menopause, they change size and create cysts that come and go. A normal ovary can at times feel concerning on pelvic exam and look concerning on ultrasound, especially in the second half of the menstrual cycle. Even postmenopausal women can have cysts on their ovaries that are completely innocent.
During my residency in the 1980's, there was great hope that regular pelvic ultrasounds and blood tests for a serum marker, CA-125, would prove to be effective screening tests. Unfortunately, these tests did not pan out.
Compared to control groups, women regularly screened with ultrasounds and CA-125 blood tests had more surgery for benign conditions that didn't actually threaten their health. And they did not have a reduced risk of dying from ovarian cancer. The ovarian cancers that were found in the screened group were often in advanced stages. The goal of finding ovarian cancer early was not met.
There have been ongoing efforts to identify women with ovarian cancer based on family history, genetic testing and a constellation of symptoms involving the pelvic organs. There have also been attempts to create more accurate ultrasound criteria for early diagnosis.
In future posts, I will discuss recent studies involving these approaches. But be forewarned — diagnosing ovarian cancer early enough to save lives remains a formidable challenge.
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