Genetics of Colorectal Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Psychosocial Issues in Hereditary Colon Cancer Syndromes
Table 14. Summary of Studies Evaluating Interest in or Intention to Have Genetic Counseling and Testing for Lynch Syndrome (LS)a
|Study Population||Nb||Interest or Intention in GC or GTc|
|CRC = colorectal cancer; FDR = first-degree relative; GC = genetic counseling; GT = genetic testing; HCCR = hereditary colon cancer registry.|
|a All studies used a cross-sectional design, with the exception of one study, which used focus groups.All studies were conducted in the United States, with the exception of one German study.|
|b Indicates number of participants older than 18 y, unless otherwise specified.|
|c Type of genetic test not specified.|
|d Unaffected = no previous diagnosis of CRC.|
|Unaffectedd FDRs of CRC patients undergoing treatment||45||51% definite GT intention; 31% probable|
|CRC patients and unaffected individuals undergoing LS GC||31 CRCs; 34 unaffected||Precounseling: 100% (29). GT intention among CRCs who were aware of GT. 92% (30) GT intention among unaffected who were aware of GT|
|Postcounseling: no one decided against testing, but 5 unaffected (18%); 1 CRC undecided|
|CRC patients, unaffected FDRs, and age/gender-matched controls recruited from HCCR and driver's license/Medicare records||105||If relative is a carrier: GT intention for 67% of CRCs; 75% of FDRs; 60% of controls|
|If insurance covers cost: GT intention for 17% of CRCs; 75% of FDRs; 40% of controls|
In several studies, higher perceived risk and worry of developing colorectal cancer were correlated with interest in or intention to have testing.[7,8,11] Other correlates found in several studies included higher perceived risk and worry of developing colorectal cancer, higher education, greater family support, preference for making one's own decision about testing, less advanced colorectal cancer, more frequent worries about colorectal cancer, belief that 50% or fewer of all colorectal cancers are hereditary, female gender, younger age, and ethnicity.[7,8,11,12,13,14,16] Participants in these studies cited many reasons for and against undergoing genetic testing. Perceived advantages of having information as a result of genetic testing included the ability to help other family members, especially children; engage in more informed health decision-making, particularly in regard to screening; plan for the future; and gain reassurance. Disadvantages included the possibility of insurance discrimination if one is found to carry a cancer-predisposing mutation, adverse psychological outcomes, and costs associated with testing.
Interest in genetic testing for children
A key difference between genetic testing for CRC and FAP concerns the appropriateness of testing persons younger than 18 years. Genetic testing for adult-onset hereditary cancers is not recommended for minors because the medical and psychosocial benefits of such testing are not realized until adulthood. Genetic testing for FAP, however, is presently offered to children with affected parents, often at the age of 10 to 12 years, when endoscopic screening is recommended. Because it is often necessary to diagnose FAP before age 18 years to prevent colorectal cancer and because screening and possibly surgery are warranted at the time an individual is identified as an APC mutation carrier, genetic testing of minors is justified in this instance.