Genetic testing beneficial for limited number of cancer disorders

December 01, 2003

OTTAWA — The use of genetic tests to identify individuals with a genetic susceptibility to develop cancer is unjustified in the clinical management of many hereditary cancer predisposing syndromes, concludes a new report by the Canadian Coordinating Office for Health Technology Assessment.

The report examines the 20 most common hereditary cancer predisposing syndromes. For each syndrome, the report outlines the genetic tests used for screening and diagnosis, the analytical and clinical validity of the tests, their cost, and the impact on the clinical management of patients with the syndrome. The report also lists genetic testing services and laboratories for hereditary cancers in Canada.

Of the 20 syndromes examined, genetic testing is helpful in the clinical management of affected families for only 6 syndromes. There is insufficient clinical benefit for genetic testing to be considered part of standard clinical management for 9 syndromes and the clinical benefit is unclear for the remaining 5 syndromes.

Typically, a genetic test is not considered part of clinical management if confirming that a person has the hereditary cancer predisposing syndrome would not impact their clinical care.

“When a test has a poor ability to predict clinical outcomes or there is no effective treatment for the cancer, testing is difficult to justify on either medical or social grounds,” said lead author Dr. Chuong Ho.

Genetic tests are used in the diagnosis or screening of hereditary cancers, and they comprise the entire spectrum of modern molecular biological techniques. However, the ability of genetic tests to predict that a patient will develop cancer is unclear as this is influenced by many factors. The tests themselves have technical limitations.

The full report is available on-line at www.ccohta.ca

CCOHTA is an independent not-for-profit organization that provides unbiased, reliable information about health technologies. CCOHTA delivers a health technology assessment program and the Common Drug Review. CCOHTA is funded by the Canadian federal, provincial and territorial governments.

For more information contact:
Kirk Fergusson: Director, Communications, CCOHTA
kirkf@ccohta.ca