New Test for Ovarian Cancer Finds More Cases

In the study, more than 46,000 women ages 50 and older underwent yearly blood tests to check their levels of a protein called CA125, which is produced by most ovarian cancers. The researchers created a computer program to assess a woman's risk of ovarian cancer based on a number of factors, including how her levels of CA125 changed over the years. In contrast, current methods used to screen for ovarian cancer involve checking to see whether CA125 levels are above a certain threshold at a single point in time.

In the study, the researchers used their computer program to determine whether women were at increased risk for ovarian cancer, but if the results suggested they were, the women were then referred for an additional blood test or an ultrasound. Ultimately, the women underwent surgery if they were determined to be at very high risk for ovarian cancer.

During the 14-year study, 640 women underwent surgery for suspected cancer, and 133 of them turned out to indeed have ovarian cancer. Meanwhile, an additional 22 women in the study developed ovarian cancer that wasn't caught by the screening test.

"Our findings indicate that this can be an accurate and sensitive screening tool, when used in the context of a woman's pattern of CA125 over time," study researcher Dr. Ian Jacobs, an OB-GYN who is currently president of The University of New South Wales, Australia, said in a statement. "It is the change in levels of this protein that's important," because what's normal for one woman may not be so for another, Jacobs said.

In fact, more than half of the women in the study who were ultimately diagnosed with ovarian cancer had CA125 levels that were within the "normal" range, the study found. [5 Things Women Should Know About Ovarian Cancer]

There is currently no recommended method for routine ovarian cancer screening, because screening for CA125 alone has been found to be unreliable in detecting ovarian cancer, but the new results are encouraging, the researchers said.

However, the new study wasn't able to determine whether the new screening test caught ovarian cancers early enough to save lives — that result is expected in an upcoming study, the researchers said.

In addition, the researchers noted that about 70 percent of the women who underwent surgery for suspected ovarian cancer (441 women total) did not have ovarian cancer — their surgeries showed that the ovaries were normal, or they had a benign condition. Unnecessary surgeries are concerning, although the percentage of surgeries that were done that turned out to be unnecessary in the new study was lower than in those of earlier studies, which used different ovarian cancer screening methods, the researchers said.

Although the results of the study appear promising, the researchers "did not assess for the increased health care cost that comes with screening all low risk women," said Dr. Emese Zsiros, an assistant professor of Oncology at Roswell Park Cancer Institute in Buffalo, New York, who was not involved in the study. Some of the additional tests that follow screening may also be unnecessary and cause anxiety, Zsiros said.

In addition, because ovarian cancer is relatively uncommon, with about 50 cases per 100,000 women over age 50, "the fear is always there that screening might lead to too many surgeries on women without ovarian cancer for each case of ovarian cancer [that is found]," Zsiros said.

The new study only considered cancers of the surface of the ovary (epithelial ovarian cancer), which are the most common type of ovarian cancer.

The study, which was led by researchers at the University College London, published today (May 4) in the Journal of Clinical Oncology.

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