Clinical criteria

Patient with the Amsterdam or the Bethesda criteria

If you have been diagnosed with colorectal cancer (or other cancer from the HNPCC spectrum) and fit the Amsterdam or the Bethesda criteria, you can do a genetic test straightway if you want, without having first an MSI test.

The clinical criteria show that your family is a definite candidate for a cancer risk study by genetic testing.

Patient without Amsterdam criteria or Bethesda criteria

If you have been diagnosed with colorectal cancer (or other cancer from the HNPCC spectrum) but do not meet the Amsterdam or Bethesda criteria, screening for tumor cell mutations (by MSI or IHC) is indispensable to decide if you should have (or not) a genetic test.

What if you meet the Amsterdam criteria, but you do not have any sick relatives alive?

If you have never been diagnosed with cancer but have a high-risk family history (so you meet the Amsterdam criteria), there might be the possibility of testing, by immunohistochemistry or MSI, the tumor of a close relative. Usually, samples from all tumors removed are stored in the Hospital where the operation took place. Preferably, belonging to a family member diagnosed with cancer at young age. If the result is positive, then there is a chance that you need a genetic test.

Discuss with your doctor what to do in your, and your family’s circumstances.

CRITERIA AND TESTING FOR TUMOR 

A family history of the disease is very important when considering the possibility of doing the genetic study of a patient. In such a way, that all patients meeting the Bethesda criteria have their biopsies or surgically removed tumors routinely tested for MSI (microsatellite instability) and Kras. As evidências da história familiar de doença são muito importantes para o estudo genético. 

MSI and Kras are both prognostic markers of colorectal cancer; in fact, a positive MSI is a good indicator of colorectal cancer and, consequently, of the need to do a genetic test (if the person/family wants to). This because the disease and MSI are caused by abnormalities in the same genes.
The results of the MSI and Kras tests also contribute for a decision on the treatment itself.

It is recommended that the first to be tested should be a family member diagnosed with colorectal cancer at a younger age.