The Amsterdam criteria for colorectal cancer (CRC) are a set of clinical guidelines used to identify families who are likely to have Lynch syndrome, the most common cause of hereditary colorectal cancer. To meet the Amsterdam criteria, the family must satisfy all of the following requirements:
- At least three relatives must have histologically verified colorectal cancer (or an associated Lynch syndrome cancer, such as endometrial, stomach, small bowel, ovarian, ureter, or renal pelvis cancer).
- One affected relative must be a first-degree relative of the other two.
- At least two successive generations must be affected.
- At least one cancer must be diagnosed before age 50 years.
- Familial adenomatous polyposis (FAP) must be excluded. If more than 100 adenomatous polyps are diagnosed, the criteria are not fulfilled.
In simpler terms, a family history that raises suspicion for Lynch syndrome based on the Amsterdam criteria involves:
- Having at least three family members with colorectal or Lynch syndrome-related cancers.
- These cancers occurring in multiple generations (parent to child, etc.).
- A close relationship between affected relatives (direct family line).
- Early onset of cancer (at least one diagnosis before age 50).
- Ruling out FAP by excluding diagnoses of more than 100 adenomatous polyps.
It's important to note that the Amsterdam criteria are highly specific but not very sensitive. This means that while they are good at identifying families with Lynch syndrome when all criteria are met, many families with Lynch syndrome do not meet these strict criteria. Therefore, modified or revised criteria (e.g., the Bethesda guidelines) have been developed to identify a broader range of individuals who should be considered for genetic testing for Lynch syndrome. These modified guidelines consider a broader range of cancers and age criteria.
