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Genetics of Colorectal Cancer (PDQ®): Genetics - Health Professional Information [NCI] - Psychosocial Issues in Hereditary Colon Cancer Syndromes

Table 15. Summary of Studies Evaluating Attitudes Toward, Interest in, or Intention to Use Assisted Reproductive Technology (ART) for FAPa, LSb, and PJSa

Study PopulationNcInterest or Intention in ARTComments
FAP = familial adenomatous polyposis; GT = genetic testing; LS = Lynch syndrome; PGD = preimplantation genetic diagnosis; PJS = Peutz-Jeghers syndrome; PND = prenatal diagnosis.
a Studies used a cross-sectional design and were conducted in the United States,[27]and in the Netherlands.[20,30].
b Participants were invited to complete questionnaires before clinical genetic testing for LS and at 3 months and 1 year after disclosure of genetic test results.
c Indicates number of participants older than 18 y, unless otherwise specified.
d Represents the number who indicated that they were considering having children in the future, out of a total of 130 individuals who answered a questionnaire prior to genetic testing[29].
FAP-affected individuals[27]2095% would consider prenatal GT for FAP; 90% would consider PGD; 75% would consider amniocentesis or chorionic villous sampling 
FAP-affected individuals[20]34133% would consider PND for FAP; 30% would consider PGD; 15% felt terminating pregnancy for FAP was acceptable24% and 25% of patients did not respond to questions about attitudes toward PND and PGD, respectively.
Individuals undergoing genetic testing for LS[29]48d21% would consider PND and/or PGD; 19% would consider only PND; 2% would consider only PGDAt 1 year after disclosure of GT results, two out of nine mutation carriers reported that they were considering PGD for future pregnancy.
PJS-affected individualsa[30]5215% indicated that pregnancy termination was acceptable if PND identified a fetus with PJS; 52% indicated PGD was acceptable for persons with PJSTen (19%) individuals, nine of whome were female, reported that they had decided not to conceive a child because of PJS.

Issues With Informed Consent for Microsatellite Instability (MSI) and Immunohistochemical (IHC) Tumor Testing

Advocacy for universal screening of all colorectal tumors for MSI and IHC to detect the absence of MMR proteins has increased.[31,32] This protocol could lead to increased identification of LS individuals and families;[33] however, there is an ongoing discussion about best practices for the informed consent process for this tumor testing.[34] MSI alone does not definitively establish a germline mutation in an MMR gene. IHC, on the other hand, can point to a specific underlying germline genetic defect because of the absent expression of a mismatch repair (MMR) protein (if methylation has been excluded). IHC results inform subsequent gene-specific mutation testing and therefore can be a surrogate for a LS diagnosis.[33,35]

It is generally advised that identification of genetic predisposition to cancer mandates explicit informed consent because of concerns for the possibility of insurance discrimination (irrespective of the Genetic Information Nondiscrimination Act of 2008), adverse psychological outcomes, and costs associated with further testing.[36,37] The Evaluation of Genomic Applications in Practice and Prevention working group specifically recommends obtaining informed consent for MSI or IHC testing.[31] Nevertheless, debate about this issue continues, partially because of pragmatic concerns surrounding the feasibility of obtaining such consent prior to the procedure. One proposed approach suggests a preparatory conversation informing patients prior to their procedure that CRC runs in families and that if their tumor has features characteristic of a heritable type, they will be contacted by a genetic health care provider for further assessment of the genetic basis of their cancer.[34] A cross-sectional survey of U.S. cancer programs (20 National Cancer Institute–designated comprehensive cancer centers and 49 community hospital cancer programs) found that, of those that performed MSI and/or IHC testing as part of standard pathologic evaluation at the time of colon cancer diagnosis in all or select cases, none required written informed consent prior to tumor testing.[38]

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WebMD Public Information from the National Cancer Institute

Last Updated: February 25, 2014
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.
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