The Amsterdam criteria are used to help identify families who may have Hereditary Non-Polyposis Colorectal Cancer (HNPCC), also known as Lynch syndrome. Familial adenomatous polyposis (FAP) must be excluded from the diagnosis when applying these criteria.
Here's a breakdown of the Amsterdam I criteria, which is also sometimes referred to as the "classic" Amsterdam criteria:
Amsterdam I Criteria (Classic ICG–HNPCC Criteria)
To meet the Amsterdam I criteria, all of the following conditions must be met:
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At least three relatives must have a confirmed diagnosis of colorectal cancer (CRC) or an HNPCC-associated cancer. HNPCC-associated cancers include cancers of the endometrium, stomach, ovary, ureter, renal pelvis, brain, small bowel, and sebaceous gland tumors.
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One affected individual should be a first-degree relative of the other two. This means that they should be parent, sibling, or child of one of the other affected relatives.
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At least two successive generations should be affected. This demonstrates a clear inherited pattern of cancer.
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At least one CRC tumor should be diagnosed before the age of 50 years. This early onset is a characteristic feature of HNPCC.
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Familial adenomatous polyposis (FAP) should be excluded. This is crucial, as FAP is a separate genetic condition that also causes colorectal cancer but through a different mechanism (numerous polyps). Exclusion typically involves pathology review or genetic testing to confirm the absence of an APC gene mutation, the gene responsible for FAP.
It's important to note that the Amsterdam criteria are highly specific but not very sensitive, meaning that while they are good at identifying true cases of HNPCC, they may miss some families who do have the syndrome but don't meet all the criteria. Therefore, the Bethesda guidelines were developed to broaden the criteria for HNPCC screening and further molecular testing.
