Genetic tests for hereditary cancer predisposing syndromes
Individuals with hereditary cancer predisposing syndromes are at an increased risk of developing cancer. These syndromes can be diagnosed clinically, but in many instances, genetic tests must be conducted to make or refine the diagnosis.
Genetic tests, which can be used for diagnosis or screening, are required to detect a genetic alteration in an affected person. Diagnostic molecular genetic testing comprises the spectrum of modern molecular biological techniques.
The overall effectiveness of using genetic tests to predict the likelihood of cancer is to be determined, given their limitations. The ability to detect a genetic alteration depends on many factors, including the gene, the nature of the mutation and the sensitivity and specificity of the test. The predictive power of genetic testing is also influenced by the complex interaction between genetic predisposition and environmental influences. There are unique social, ethical and legal issues related to genetic testing.
- To determine the analytical and clinical validity, availability and cost of genetic tests for the screening and diagnosis of hereditary cancer predisposing syndromes.
- To document the impact of genetic testing on the clinical management of patients with hereditary cancer predisposing syndromes.
A systematic review was conducted using a literature search strategy. Based on predetermined selection criteria for included studies, two independent reviewers identified 457 relevant articles. The molecular genetic tests available and their impact on clinical management were investigated for 20 syndromes. A list was compiled of molecular techniques used to detect the most common hereditary cancer predisposing syndromes, their analytical and clinical sensitivity, their cost and their availability. Genetic testing services and laboratories for hereditary cancers in Canada were also listed.
- Genetic testing for many types of hereditary cancers is far from satisfactory because of the relatively high costs of genetic tests; their variable analytical and clinical validity; and their limited availability.
- Given the rapid development of new molecular techniques and the demand for access, implementing genetic tests into clinical management is justified for some disorders.