Background: Identification of a genetic basis underlying certain types of cancer has led to an increase in demand for genetic counseling about individual risks of the disease. We conducted a systematic review of the literature to determine the quality and strength of evidence relating to psychological outcomes of genetic counseling for familial cancer.
Methods: Six electronic databases were searched to identify controlled trials and prospective studies that examined the effect of genetic counseling on risk perception, knowledge, anxiety, cancer-specific worry, depression, and cancer surveillance. Twenty-one studies from 25 papers met inclusion criteria, including five controlled trials and 16 prospective studies. Analysis of each outcome was stratified by short-term (</=1 month) and long-term (>/=3 months) follow-up. Trial evidence was assessed with standardized differences of the means at follow-up between intervention and comparison groups, and these data were pooled by use of random-effects meta-analysis.
Results: Meta-analysis of controlled trials showed that genetic counseling improved knowledge of cancer genetics (pooled short-term difference=0.70 U, 95% confidence interval (CI)=0.15 to 1.26 U) but did not alter the level of perceived risk (pooled short-term difference=-0.10 U, 95% CI=-0.23-0.04 U). Prospective studies reported improvements in the accuracy of perceived risk. No effect was observed in controlled trials on general anxiety (pooled long-term effect=0.05 U, 95% CI=-0.21-0.31 U) or cancer-specific worry (pooled long-term difference=-0.14 U, 95% CI=-0.35-0.06 U), although several prospective studies demonstrated short-term reductions in these outcomes. Few studies examined cancer surveillance behaviors, and no studies attempted to measure informed choice.
Conclusions: Genetic counseling for familial cancer is associated with improvement in knowledge but does not have an adverse effect on affective outcomes. We urge further investigation of these findings through well-designed, well-reported, randomized controlled trials with suitable comparison groups and additional outcome measures [J Natl Cancer Inst 2004; 96:122-33].