Table 2

Molecular testing strategies in hereditary colorectal cancer (CRC)

Risk categorySomatic or constitutive testingEligibilityTest
Family history of CRCSomaticModerate-risk or high-risk family historydMMR/pMMR
ConstitutiveAmsterdam criteria112 families where MMR testing is not possiblePanel testing of affected individuals or unaffected testing
CRCSomaticUniversal testingdMMR/pMMR and subsequent testing as defined by NICE DG27 guideline5 7 8 18 112
Early onset CRC (EOCRC)ConstitutiveDiagnosis of CRC at 30 years and underPanel testing determined by MMR status
Lynch-like syndromeSomaticdMMR tumours without hypermethylation/BRAF pathogenic variant and no constitutional pathogenic variant in MMR genesSomatic testing panel
Serrated polyposis syndromeConstitutive/
somatic
Diagnosis of exclusionExclude known predisposition syndromes
Multiple colorectal adenoma (MCRAs)ConstitutiveMCRAs under 60 years of age with ≥10 adenomas, or patients over 60 years of age with ≥20 adenomas, or ≥10 with a family history of multiple adenomas or CRCGene panel testing
  • dMMR, MMR proficient; MMR, mismatch repair; NICE, National Institute for Health and Care Excellence; pMMR, MMR deficient.