Outcomes of genetic evaluation for hereditary cancer syndromes in unaffected individuals.

Gustafson SL1, Raymond VM, Marvin ML, Else T, Koeppe E, Stoffel EM, Everett JN.

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Abstract

Genetic testing (GT) for inherited cancer predisposition is most informative when initiated in individuals with cancer, thus standard practice recommends GT start in an affected individual. This strategy can be frustrating for unaffected consultands and providers. Retrospective review of cases was performed to compare outcomes of testing the unaffected consultand and recommending that testing start in an affected relative. Records from cancer-free consultands (N = 101), presenting to the University of Michigan Cancer Genetics Clinic between 6/1/2011 and 12/30/2011 were reviewed. All genetics records for these consultands were reviewed through 3/31/2013 for GT recommendations (117 total). The unaffected consultand was offered testing in 14.5 % of cases, testing was completed in 64.7 % of these with one mutation identified. Of consultands tested initially, 70.5 % received cancer-screening recommendations based on family history and test results. Testing was recommended to start in an affected family member in 30.7 % of cases. Fifty percent returned to clinic with information on an affected family member; 83.3 % documented that their family member underwent GT with one mutation identified. Consultands reported the affected family member refused testing in 22.2 % and two of these consultands subsequently pursued GT, identifying one mutation. Fifty percent of cases where testing the family member first was recommended were lost to follow-up with 66.6 % of these never given cancer-screening recommendations. Cancer genetic risk evaluation of healthy consultands should consider the option of pursuing GT in the unaffected consultand and should implement a plan for tailored risk management in the absence of informative genetic evaluation within the family.