Gene Tests To Identify Ovarian Cancer Have Little Clinical Value

Main Category: Ovarian Cancer
Also Included In: Cancer / Oncology;  Genetics
Article Date: 23 Oct 2006 - 0:00 PDT

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Many genomic tests that are currently used to diagnose and guide treatment of ovarian cancer are not shown to decrease the number of women who die from the disease or improve their quality of life, according to a new evidence report supported by a partnership of the Agency for Healthcare Research and Quality, the Centers for Disease Control and Prevention's Division of Cancer Prevention and Control, and CDC's National Office of Public Health Genomics.

Ovarian cancer causes more deaths than any other cancer of the female reproductive system. More than 20,000 women are diagnosed with the disease annually, and approximately 15,000 die from it. The risk for ovarian cancer increases with age and most often is diagnosed in white women over the age of 50. If diagnosed during stage I, ovarian cancer has a survival rate of over 90 percent. However, most cases are diagnosed in advanced stages, when the cancer has spread to other organs.

Physical exams, ultrasounds, and other routine screening efforts for reducing the number of women affected by the disease, and in turn the number who die from it, have been unsuccessful compared with similar efforts aimed at other causes of cancer deaths in women. Because current strategies have not proven to be effective, there is tremendous interest in identifying the disease in its earliest stages by looking at genes, gene expression levels, proteins, and tumor markers. These tests focus on (1) detecting a gene-based tumor marker, such as CA-125, or (2) identifying genetic mutations such as BRCA1 and BRCA2 that indicate increased risk for developing cancer, or (3) identifying genetic changes that predict response to therapy in women with ovarian cancer.

Researchers performed a comprehensive review of the literature and found few studies evaluated genetic tests other than CA-125 or BRCA1 and BRCA2 to diagnose ovarian cancer or identify women at risk. Among the tests evaluated in the report, the researchers found no studies showing that changing treatment based on test results reduced deaths or improved quality of life in women who were diagnosed with ovarian cancer. There are few data on the harms of gene-based tests for ovarian cancer, including the psychological impact of false-positive tests or delays in treatment that can result from a false-negative test.

A computer simulation model developed by the research team suggests that screening, even with the highly accurate tests, will not result in large reductions in deaths from ovarian cancer unless testing is very frequent (less than 1 year between tests). However, such frequent screening would also yield a large number of false-positive test results. The team stated that research aimed at improving treatment options and the discovery of treatment, lifestyle, or dietary choices that could prevent ovarian cancer would likely offer greater promise for major reductions in deaths from the disease.

"Ovarian cancer and its effects can be devastating for women diagnosed with the disease. The findings from this report will help to guide further research aimed at better treatment that may lead to fewer deaths from ovarian cancer," said Jean R. Slutsky, Director of AHRQ's Center for Outcomes and Evidence.

This report is the first of a series of five evidence reports that are part of an inter-agency collaboration between AHRQ and CDC. As part of the CDC-supported Evaluation of Genomic Applications in Practice and Prevention (EGAPP) project, the EGAPP working group will evaluate the evidence presented in the report and make recommendations in the near future about the use of these tests for screening, diagnosis, and treatment of ovarian cancer. Other evidence reports requested by EGAPP will evaluate the use of genetic tests for specific diseases or conditions, such as determining an individual patient's response to drugs used in the treatment of depression.

"This first-ever collaboration of the CDC's cancer and genomics programs with AHRQ provides important evidence-based guidance to inform both public health and medical practitioners about the appropriate use of genetic testing in cancer prevention and control," said Janet Collins, Ph.D., Director of CDC's National Center for Chronic Disease Prevention and Health Promotion.

Agency for Healthcare Research and Quality (AHRQ)
540 Gaither Rd.
Rockville, MD 20850
United States
http://www.ahrq.gov/news/vnewsix.htm

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