Uptake of genetic testing by relatives of lynch syndrome probands: a systematic review

Screening of persons with newly diagnosed colorectal cancer for Lynch syndrome can yield substantial benefits at acceptable costs, presuming sufficient uptake of genetic testing by first-degree relatives of Lynch syndrome probands. We performed a systematic review of the literature to determine the frequency of and factors associated with genetic testing of first-degree relatives of Lynch syndrome probands.

We searched 4 databases (CINAHL, PsycInfo, PUBMED, and SCOPUS) for articles published through May 2011 reporting uptake of genetic testing by relatives of Lynch syndrome probands. Two investigators independently screened articles to determine whether they met inclusion criteria; data were collected on study population, genetic counseling, and genetic testing. A narrative, qualitative systematic review was performed.

We identified 1258 potentially relevant articles; 533 underwent full-text review, and 8 were included in the final analysis. Of first-degree relatives of Lynch syndrome probands, 52% or less received genetic testing. For each proband, 3.6 or fewer relatives underwent genetic testing. Demographic factors (age <50 years, female sex, parenthood, level of education, employment, participation in medical studies), psychological factors (lack of depressive symptoms), and possibly family history (greater number of relatives with cancer) were associated with uptake of genetic testing.

Genetic testing appears to be underutilized by first-degree relatives of patients with Lynch syndrome. The clinical benefit and economic feasibility of screening persons with colorectal cancer for Lynch syndrome depend on optimizing family-wide uptake of genetic testing. Future research and clinical efforts should focus on ways to overcome barriers to genetic testing.