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Many Gene-Based Ovarian Ca Tests Don’t Lower Mortality

Many Gene-Based Ovarian Ca Tests Don’t Lower Mortality

ROCKVILLE, Maryland--Clinical studies do not validate the power of many genomic tests developed to diagnose and guide the treatment of ovarian cancer to decrease the disease's mortality or improve the quality of life of patients, according to a report released by the Agency for Healthcare Research and Quality (AHRQ). The medical-literature review evaluated tests for single-gene products, genetic variations affecting the risk of ovarian cancer, gene expression, and proteomics.

Laboratory Data
"There are reasonable data on the clinical laboratory performance of most radioimmunoassays, but the majority of the data on other genomic tests comes from research laboratories," the report said. "Although research remains promising, adaptation of genomic tests into clinical Many Gene-Based Ovarian Ca Tests Don't Lower Mortality practice must await appropriately designed and powered studies in relevant clinical settings."

Current strategies have failed to provide effective ways to prevent and screen for ovarian cancer. As a result, investigators have explored genomics and proteomics to identify potential biomarkers that could help reduce the morbidity and mortality of the often-fatal disease, which strikes more than 20,000 American women annually. Key findings from the report include:

  • Published data on clinical laboratory performance suggest that currently available radioimmunoassays for singlegene products have acceptable reproducibility and reliability, but the level of variability may have some impact on the clinical interpretation of results.
  • Insufficient evidence exists to estimate how newer technologies, such as microarrays or protein profiles, would perform in a typical clinical laboratory.
  • Other than CA-125, single-gene products have yet to show an ability to diagnose ovarian cancer in symptomatic or asymptomatic women. "Small sample sizes, lack of detail on the prediagnosis history of patients, and an unrealistically high prevalence of ovarian cancer in the majority of studies make it difficult to assess how any of these tests would perform in clinical practice," the report said. The report noted that estimating the clinical value of more complex tests, using multiple genes and/or protein markers, is even more difficult.
  • The review failed to identify any evidence that tests other than CA-125 can detect ovarian cancer in asymptomatic women.
  • Although evidence suggests that genomic tests, particularly CA-125, can indicate differential outcomes, the review found no studies showing that changes in case management based on the results of the tests lead to improved outcomes. A previous evidence report found that CA-125 can help distinguish between malignant and benign tumors in postmenopausal women.
  • Few data exist on the harm of genebased testing for ovarian cancer, including the psychological effects of receiving a false-positive finding or having treatment delayed because of a false-negative report.

Based on a computer simulation model developed by the team, the researchers concluded that even highly accurate screening tests will not result in a large drop in the ovarian cancer mortality rate unless testing is done at intervals of less than 1 year. Such frequent testing, however, would also yield a large number of false-positives results.

The study, "Genomic Tests for Ovarian Cancer Detection and Management," was conducted by Evan R. Myers, MD, and his colleagues at the Duke University Evidence-based Practice Center, which is funded by AHRQ. It is the first of five evidence reports to be issued as part of a collaboration between AHRQ and the Centers for Disease Control and Prevention.

 
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