Interest in single nucleotide polymorphism (SNP) genetic testing for colon cancer risk in primary care patients

BACKGROUND: Single nucleotide polymorphisms (SNPs) are the most common genetic variations in the human genome. Whereas rare high-penetrance cancer susceptibility genes (e.g., hMSH2/hMLH1) convey large increases in cancer risk, SNPs convey much smaller risks. SNP testing is available through on-line commercial companies, although the public's understanding of genomic information and the clinical utility of such testing remain unknown.

METHODS: We conducted 4 focus groups with 24 primary care patients to investigate interest in colon cancer SNP testing. Each focus group participated in a risk communication discussion that used images, text, and graphs to convey the small amount of risk related to colon cancer SNPs. Participants completed pre- and post-discussion surveys assessing demographics and interest in colon cancer SNP testing.

RESULTS: Most participants (54%) reported being “very interested” in receiving a colon cancer SNP test that showed an increased lifetime risk from 6% to 7.5%. Fewer participants (33.3%) reported being “very interested” in SNPs that decreased risk. Interest level did not change after the risk communication discussion. Cancer survivors reported less interest in SNP testing (Χ²=7.14, p=0.028). Demographic factors and family history of cancer were unrelated to interest in SNP testing. Participants stated concerns about privacy of genomic information and expressed preferences for obtaining SNP test information from health care professionals.

CONCLUSION: Primary care patients indicated strong interest in SNP testing even after a risk communication discussion. Future work can develop SNP testing educational tools and further explore whether and how genomic information can be used by health care providers.