ASCO Annual Meeting
June 3, 2011
A large study evaluating ovarian cancer screening showed that using both a CA-125 blood test and transvaginal ultrasound to find early ovarian cancer did not reduce the risk of dying from the disease and resulted in unnecessary follow-up procedures. The CA-125 blood test measures the amount of a tumor marker called CA-125, which may be found in higher levels in women with ovarian cancer. A transvaginal ultrasound uses sound waves to create pictures of the ovaries. Both tests are used to evaluate the symptoms of ovarian cancer, its stage, and the effectiveness of treatment.
In this study, nearly 80,000 women ages 55 to 74 were offered annual CA-125 testing for six years and transvaginal ultrasound for four years, or they received the usual care and were not offered these screening tests. Researchers followed the women for 13 years to see whether the number of women diagnosed with ovarian cancer was different between the two groups, and whether the women who did not receive screening had an increased risk of dying from ovarian cancer.
The results showed that there was very little difference in the number of women who developed or died from ovarian cancer. It was diagnosed in 212 women who received screening compared with 176 who did not, and 118 women who received screening died from ovarian cancer compared with 100 women who did not receive screening.
Researchers also found a high number of false positive test results for the women who received screening. A false positive is when a test result indicates a person may have cancer when they do not. When screening indicates a woman may have cancer, additional procedures are needed to check for cancer, such as surgery to get a sample of the ovaries to check for cancer. These types of procedures have risks that would be considered unnecessary if a woman does not have cancer.
What this means for patients
“There hasn't been a good method for the early detection of ovarian cancer. CA-125 and transvaginal ultrasound are useful in measuring disease, so we evaluated whether these tests would identify ovarian cancer early, at a stage in which it is more likely to be cured,” said lead author Saundra Buys, MD, Professor of Medicine at the University of Utah and Huntsman Cancer Institute in Salt Lake City. “This study shows that the available screening tests are not effective and may actually cause harm because of the high number of false positives. These results point to the continued need for more precise and effective screening tools for this disease.” Screening with these tests is still appropriate for women with a strong family history of ovarian cancer or for women with symptoms or if abnormal changes are found during a physical examination.
Questions to ask your doctor
- What is my risk of ovarian cancer?
- What are the symptoms of ovarian cancer?
- If I have symptoms of ovarian cancer, what type of testing do you recommend?
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