CA-125, transvaginal ultrasound for early detection did not reduce ovarian cancer mortality

Issue: July 10, 2011

2011 ASCO Annual Meeting

Screening with a CA-125 blood test and transvaginal ultrasound for early detection of ovarian cancer did not reduce the risk for disease-specific death, and resulted in a high number of false positives and unnecessary biopsies.

The results from the PLCO Screening trial of nearly 80,000 women showed that the available tests are ineffective and potentially dangerous, said Saundra Buys, MD, professor of medicine at the University of Utah and Huntsman Cancer Institute in Salt Lake City. Buys is scheduled to present the results at the 2011 ASCO Annual Meeting.

“It’s important to remember this was done as a screen. The test wasn’t done to evaluate symptoms in women who had abdominal pain, cramping or bloating, and it wasn’t done specifically in a high-risk population,” she told HemOnc Today. “With those caveats, we can say the screening as it was performed in the PLCO trial did not reduce the likelihood of dying from ovarian cancer. If a woman has symptoms, this may end up a useful test, but the screen as it was performed did not reduce the risk for mortality.”

From 1993 to 2001, women aged 55 to 74 were assigned to either annual screening (n=39,105) or usual care (n=39,111). Women in the screening arm were offered CA-125 testing for 6 years and transvaginal ultrasound for 4, and followed for up to 13 years.

Buy said there was no statistically significant difference in ovarian cancer incidence or mortality between the two arms. There were 212 women diagnosed with cancer in the screening arm compared with 176 in the usual care arm. Researchers recorded 118 deaths in the screening group vs. 100 in the usual care arm.

Further, there were 3.285 false positives recorded in the screening arm compared with only 212 true positives. Almost 1,100 women with a false positive result underwent biopsy and 163 had serious complications.

“In terms of screenings in general, we know that one of the really important things when screening for disease is the commonness of the population. If you have a rather uncommon disease like ovarian cancer and you have a screening test that is not perfect, the likelihood of that screening test finding cancer is lower than the likelihood of that screening test finding benign disease.” – by Jason Harris

For more information:

Buys SS. #5001. Presented at: 2011 ASCO Annual Meeting; Chicago; June 3-7, 2011.

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