HemeOnc

Hereditary Nonpolyposis Colorectal Cancer

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Hereditary Nonpolyposis Colorectal Cancer, Hereditary Non-polyposis Colorectal Cancer, Lynch Syndrome, HNPCC

  • See Also
  1. Colonic Polyp
  2. Colorectal Cancer Screening
  3. Colorectal Cancer Prevention
  4. Colorectal Cancer
  • Epidemiology
  1. Prevalence: 1 in 440 persons (U.S.)
  2. Diagnosed on average by age 45 years
  3. Lifetime Colon Cancer risk: 75-80%
  4. Autosomal Dominant condition
  • Pathophysiology
  1. Rapid progression from advanced adenoma to Colorectal Cancer
  • Associated Conditions
  1. Colon Cancer
    1. HNPCC is the most common cause of inherited Colorectal Cancer (2-4% of cases)
  2. Endometrial Cancer
  3. Gastric Cancer (subset of families)
  • Diagnosis
  1. Patient with first degree relative with Colorectal Cancer diagnosed before age 50 years OR
  2. Genetic Testing
  1. Counseling to consider Genetic Testing
  2. Early Screening
    1. Colonoscopy starting at age 25 years (or 5 years earlier than youngest Colorectal Cancer relative)
    2. Repeat Colonoscopy every 1-2 years
  3. Genetic Testing positive or No Genetic Testing
    1. Colonoscopy every 2 years until age 40
    2. Colonoscopy yearly after age 40
    3. Continue surveillance until age 75 years old
  1. Indications
    1. HNPCC patients with Family History or Genetic Testing in which Gastric Cancer is a risk
  2. Upper endoscopy protocol
    1. Start at age 50 years (or five years before the youngest case)
    2. Repeat every 2 years until age 75 years
  • References
  1. Vasen (2013) Gut 62(6):812-23 [PubMed]
  2. Wilkins (2018) Am Fam Physician 97(2): 111-6 [PubMed]