The criteria for identifying a family as having Lynch syndrome (also known as Hereditary Non-Polyposis Colorectal Cancer or HNPCC) based on family history, sometimes referred to as the Amsterdam criteria or revised Amsterdam criteria, involves specific patterns of cancer occurrence within the family. These criteria help identify families who should undergo further genetic testing for Lynch syndrome. The original question likely refers to the revised Amsterdam criteria.
Revised Amsterdam Criteria for Lynch Syndrome
To meet the revised Amsterdam criteria, a family must fulfill all of the following requirements:
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Three or more relatives must have a Lynch syndrome-associated cancer. These cancers include:
- Colorectal cancer
- Endometrial cancer
- Small bowel cancer
- Ureter cancer
- Renal pelvis cancer
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At least two successive generations must be affected by one of these cancers.
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One affected relative must be a first-degree relative of the other two (e.g., parent, sibling, or child).
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At least one relative must have been diagnosed with cancer before the age of 50 years.
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Familial adenomatous polyposis (FAP) must be excluded if colorectal cancer is involved. Tumors should be tested for microsatellite instability (MSI).
Important Considerations
It's important to note that the Amsterdam criteria are primarily used to identify families at high risk who should undergo further genetic testing. Not all families who meet the Amsterdam criteria will necessarily have Lynch syndrome, and conversely, some families with Lynch syndrome may not meet these criteria. Other criteria such as the Bethesda guidelines, which are based on tumor characteristics, and prediction models like PREMM5, are also used to determine the need for genetic testing. Genetic testing of an affected individual is the gold standard for confirming a diagnosis of Lynch syndrome.
