Purpose: Individuals and families dealing with the possibility of hereditary cancer risk face numerous decisions, including whether to obtain genetic testing. The purpose of this article is to determine what is known about the rate at which people obtain cancer genetic testing. Methods: Using MEDLINE, CINAHL, and PSYCHINFO plus reviewing reference lists of relevant articles, we identified 40 studies in May 2002 that addressed breast cancer-related decisions, enrolled adult participants, were published in 1990 or more recently, were peer-reviewed primary clinical studies, addressed genetic testing either alone or in combination with genetic counseling, and reported rates at which participants showed interest in and/or underwent cancer genetic testing. Information regarding study design, participants, and genetic testing uptake rates was recorded. Each article was reviewed for methodologic quality using a flexible quality review system applicable to all study types. Results: Of the 40 studies, 25 provided information about hypothetical genetic testing decisions, 14 about real decisions, and 1 about both. Mean hypothetical uptake was 66% (range, 20-96%) and real uptake was 59% (range, 25-96%). Multivariate logistic regression analyses found that decision type (real/hypothetical), personal and family history of breast cancer, and variability in sampling strategy, recruitment setting, and criteria for real and hypothetical uptake were independently associated with uptake. Our systematic review identified additional explanations for uptake variability (investigator influences, small sample sizes, variability in target populations, lack of clearly described sampling strategies, sampling methods open to bias, and variability in reporting associated risk factors). Conclusion: In addition to clinical characteristics, research methodologic issues are likely to be major determinants of variability in published breast cancer genetic testing uptake rates. An understanding of these issues will clarify to clinicians why their clinical experience may not be congruent with published rates and help guide future research.
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