Response to genetic counseling and testing for the APC I1307K mutation

Abstract

The APC I1307K gene mutation is associated with increased colorectal cancer (CRC) risk in Ashkenazi Jews. Factors predicting acceptance of this and other hereditary colon cancer mutation tests in a clinical setting are unknown. We analyzed sex, age, family history, personal history, and gene test results of patients at increased risk for cancer who sought cancer risk counseling at the Johns Hopkins (JH) CRC Risk Assessment Clinic (n = 91), and those submitting samples to the JH Pathology Molecular Diagnostic Laboratory (n = 256) for APC I1307K testing. Of patients seen at the JH Clinic, 77/91 (84.6%) elected APC I1307K testing after pretest counseling (acceptors). There were no statistically significant differences in demographic characteristics between acceptors and decliners. In comparison, only 8 of 57 (14.0%) patients offered HNPCC testing proceeded with testing (P < 0.001). Of 256 individuals tested at the JH laboratory, most were male (61.3%) and most had a personal or family history of colorectal cancer or polyps. Test positivity correlated with increasing risk of colorectal cancer. Acceptance of testing for the APC I1307K mutation is high, with more men than women pursuing counseling and testing. The reported association between the APC I1307K mutation and colon cancer risk was supported by a correlation in these data between personal or family history of CRC or polyps and a gene mutation.

Factors Influencing Uptake of Genetic Testing For Colorectal Cancer Risk in an Australian Jewish Population

“…In fact, 72% of people asked stated that they definitely would have a blood test that would tell them if they were at increased risk of developing bowel cancer. These data are in line with previously published data that documented a high level of interest in genetic testing for cancer susceptibility genes in Jewish communities overseas (Johnson et al, 2000;Lehmann et al, 2002). Lehmann et al (2002) reported that 40% of Jewish women interviewed would have a BRCA genetic test and Johnson et al (2000) observed 85% of Jewish participants at a colorectal cancer risk assessment clinic would have testing to detect the APC I1307K allele.…”

“…These data are in line with previously published data that documented a high level of interest in genetic testing for cancer susceptibility genes in Jewish communities overseas (Johnson et al, 2000;Lehmann et al, 2002). Lehmann et al (2002) reported that 40% of Jewish women interviewed would have a BRCA genetic test and Johnson et al (2000) observed 85% of Jewish participants at a colorectal cancer risk assessment clinic would have testing to detect the APC I1307K allele. However, it important to note that there is frequently a high level in hypothetical interest in undertaking genetic testing for cancer susceptibility genes that does not translate into actual testing uptake (Struewing et al, 1995;Press et al, 2001;Meijers-Heijboer et al, 2000;Botkin et al, 2003).…”

“…The most commonly cited concern when considering genetic testing for cancer predisposition appeared to be the possibility of potential discrimination by insurance companies (indicated by 54% of participants as being of concern). Similar concerns have been reported in other studies for individuals undergoing genetic testing in other countries (Hudson et al, 1995;Phillips et al, 2000;Johnson et al, 2000;Lehmann et al, 2002;. Importantly, in Australia, genetic test results do not have any impact on provision or cost of health insurance, as this type of insurance is community rated.…”

“…One study has been published looking specifically at the acceptance of APC I1307K genetic testing in an American Jewish population (Johnson et al, 2000). Even though our understanding is that this is a low penetrance allele, the results suggested a level of acceptability of this testing comparable to the high penetrance bowel cancer syndrome Hereditary Nonpolyposis Colorectal Cancer (HNPCC).…”

“…Even though our understanding is that this is a low penetrance allele, the results suggested a level of acceptability of this testing comparable to the high penetrance bowel cancer syndrome Hereditary Nonpolyposis Colorectal Cancer (HNPCC). Around 85% of participants accepted the offer of testing for the APC I1307K variant after pretest genetic counseling in individuals attending a colon cancer risk assessment clinic (Johnson et al, 2000). However, our group was interested in assessing the acceptability of such testing in a more communitybased group from a local Jewish community, using a research protocol where participants knew that they would not receive a genetic test result (to help reduce ascertainment bias).…”