Table 16. Summary of Prospective Studies Evaluating Participation in Genetic Counseling and Testing for Hereditary Colorectal Cancer (CRC)a,b,c continued...
Studies also have examined the effect of LS genetic counseling and testing on cancer risk comprehension. One study reported that nearly all mutation carriers and noncarriers could accurately recall the test result 1 year after disclosure. More noncarriers than carriers correctly identified their risk of developing CRC at both 1 month and 1 year following result disclosure. Mutation carriers who incorrectly identified their CRC risk were more likely to have had lower levels of pretest subjective risk perception compared with those who correctly identified their level of risk. Another study reported that accuracy of estimating colorectal and endometrial cancer risk improved following disclosure of mutation status in both carriers and noncarriers.
Studies evaluating psychological outcomes following genetic testing for FAP suggest that some individuals, particularly mutation carriers, may be at risk of experiencing increased distress. In a cross-sectional study of adults who had previously undergone APC genetic testing, those who were mutation carriers exhibited higher levels of state anxiety than noncarriers and were more likely to exhibit clinically significant anxiety levels. Lower optimism and lower self-esteem were associated with higher anxiety in this study, and FAP-related distress, perceived seriousness of FAP, and belief in the accuracy of genetic testing were associated with more state anxiety among carriers. However, in an earlier study that compared adults who had undergone genetic testing for FAP, Huntington disease, and hereditary breast/ovarian cancer syndrome, FAP-specific distress was somewhat elevated within 1 week after disclosure of either positive or negative test results and was lower overall than the other syndromes.
In a cross-sectional Australian study focusing on younger adults aged 18 to 35 years diagnosed with FAP (N = 88), participants most frequently reported the following FAP-related issues for which they perceived the need for moderate-to-high levels of support or assistance: anxiety regarding their children's risk of developing FAP, fear about developing cancer, and uncertainty about the impact of FAP. Seventy-five percent indicated that they would consider prenatal testing for FAP; 61% would consider PGD, and 61% would prefer that their children undergo genetic testing at birth or before age 10 years. A small proportion of respondents (16%) reported experiencing some FAP-related discrimination, primarily indicating that attending to their medical or self-care needs (e.g., time off work for screening, need for frequent toilet breaks, and physical limitations) may engender negative attitudes in colleagues and managers.
Another large cross-sectional study of FAP families conducted in the Netherlands included persons aged 16 to 84 years who either had an FAP diagnosis, were at 50% risk of having an APC mutation, or were proven APC noncarriers. Of those who had APC testing, 48% had done so at least 5 years or longer prior to this study. Of persons with an FAP diagnosis, 76% had undergone preventive colectomy, and 78% of those were at least 5 years postsurgery. The study evaluated the prevalence of generalized psychological distress, distress related specifically to FAP, and cancer-related worries. Mean scores on the Mental Health Index-5, a subscale of the SF-36 that assessed generalized distress, were comparable to the general Dutch population. Twenty percent of respondents were classified as having moderate to high levels of FAP-specific distress as measured by the Impact of Event scale (IES), with 23% of those with an FAP diagnosis, 11% of those at risk of FAP, and 17% of noncarriers reporting scores in this range. Five percent reported scores on the IES that indicated severe and clinically relevant distress; of those, the majority (78%) had an FAP diagnosis. Overall, mean scores on the Cancer Worry Scale were comparable to those found in another study of families with LS. Persons with an FAP diagnosis were more likely to report more frequent cancer worries, and the most commonly reported worries were the potential need for additional surgery (26%) and the likelihood that they (17%) or a family member (14%) will develop cancer. In multivariate analysis, factors associated with higher levels of FAP-specific distress included greater perceived risk of developing cancer, more frequent discussion about FAP with family or friends, and having no children. Factors associated with higher levels of cancer-specific worries included being female, poorer family functioning, greater actual and desired discussion about FAP with family or friends, greater perceived cancer risk, poorer general health perceptions, and having been a caregiver for a family member with cancer. The authors noted that most factors that were associated with higher levels of cancer- and FAP-specific distress or worry were psychosocial factors, rather than clinical or demographic factors.