Table 1 Amsterdam criteria II and revised Bethesda guidelines.

There should be at least three relatives with colorectal cancer (CRC) or with a Lynch syndrome associated cancer: cancer of the endometrium, small bowel, ureter or renal pelvis.

- one relative should be a first-degree relative of the other two;

- at least two successive generations should be affected,

- at least one tumor should be diagnosed before the age of 50 years,

- FAP should be excluded in the CRC case if any,

- tumours should be verified by histopathological examination.

Revised Bethesda guidelines

1. CRC diagnosed in a patient aged <50 years.

2. Presence of synchronous, metachronous colorectal, or other Lynch syndrome-related tumours*, regardless of age.

3. CRC with MSI-high phenotype diagnosed in a patient aged < 60 years.

4. Patient with CRC and a first-degree relative with a Lynch syndrome-related tumor, with one of the cancers diagnosed aged <50 years.

5. Patient with CRC with two or more first-degree or second-degree relatives with a Lynch syndrome-related tumor, regardless of age.