From suspicion to follow-up

The work of oncogeneticists and genetic counselors consists of determining, given a particular personal and/or family context of cancer, whether it is indeed a hereditary predisposition. First, they reconstruct the family tree and the medical history of the family members, then offer the person a genetic analysis based on a blood test and a saliva sample to look for the presence of a genetic anomaly. 

If an alteration responsible for a predisposition is identified, genetic tests targeted at this alteration can then be offered to family members who wish to determine if they are carriers of the disease or not. Appropriate follow-up is offered to all identified carriers in the family. 

The fact that the initial analysis showed no alteration – which happens 8 times out of 10 – does not mean that there is no predisposition. "Either the techniques used to date are not sensitive enough, or the gene involved has not yet been identified," specifies Dr. Chrystelle Colas, head of the Clinical Genetics Unit. "Only research will make it possible to fill these gaps and optimize the care of the patient and their relatives." The patient and their relatives are then offered monitoring adapted to their particular situation. In certain situations it is possible to propose more advanced genetic analyses, in particular as part of the France Genomic Medicine Plan. 

In recent years, there has been an increase in requests for genetic analyses because targeted treatments associated with certain genetic abnormalities have been developed and are now available. In certain situations, which are becoming more and more varied, it is therefore important for oncologists to have the results of genetic tests that can be completed, either from the tumor, or from a constitutional sample taken at the end of an oncogenetics consultation. These tests can therefore be recommended even in the absence of a personal and/or family context suggestive of predisposition. The results of these tests then make it possible to guide the treatments in addition to allowing an adapted follow-up of the patient and their family.