Genetics of Colorectal Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Psychosocial Issues in Hereditary Colon Cancer Syndromes
Table 16. Summary of Prospective Studies Evaluating Participation in Genetic Counseling and Testing for Hereditary Colorectal Cancer (CRC)a,b,c continued...
In a study of cancer-affected and cancer-unaffected persons who fulfilled clinical criteria for LS, 92% reported having had a colonoscopy and/or flexible sigmoidoscopy at least once before genetic testing. Another study of unaffected individuals presenting for genetic risk assessment and possible consideration of LS, FAP, or APC I1307K genetic testing reported that 77% had undergone at least one screening exam (either colonoscopy, flexible sigmoidoscopy, or barium enema).
Three studies determined whether cancer-unaffected persons adhered to LS colonoscopy screening recommendations before genetic testing, and reported adherence rates of 10%, 28%, and 47%.
Several longitudinal studies examined the use of screening colonoscopy by cancer-unaffected persons after undergoing testing for a known LS mutation.[57,74,75,76] These studies compared colonoscopy use before LS genetic testing with colonoscopy use within 1 year after disclosure of test results. One study reported that LS mutation carriers were more likely to have a colonoscopy than were noncarriers and those who declined testing (73% vs. 16% vs. 22%) and that colonoscopy use increased among carriers (36% vs. 73%) in the year after disclosure of results. Two other studies reported that carriers' colonoscopy rates at 1 year after disclosure of results (71% and 53%) were not significantly different from rates before testing,[74,76] though noncarriers' colonoscopy rates decreased in the same time period. Factors associated with colonoscopy use at 1 year after disclosure of results included carrying a LS-predisposing mutation,[74,75,76] older age, and greater perceived control over CRC. These findings suggest that colonoscopy rates increase or are maintained among mutation carriers within the year after disclosure of results and that rates decrease among noncarriers. Data from a longitudinal study including 134 MMR mutation carriers with and without a prior LS-related cancer diagnosis found that those who did not undergo colonoscopy for surveillance within 6 months after receiving genetic test results were six times more likely to report clinically significant depressive symptoms as measured by the Center for Epidemiological Studies-Depression (CES-D) scale (odds ratio [OR], 6.06; 95% confidence interval [CI], 2.09–17.59). Higher levels of CRC worry measured prior to genetic testing also were associated with clinically significant depressive symptoms (OR, 1.53; 95% CI, 1.19–1.97).