Is cancer hereditary, and when should a family consider genetic counselling?
Cancer involves genetic changes, but most arise during life rather than being inherited. A minority are linked to inherited susceptibility. Certain family patterns or unusually early diagnoses may justify counselling, but a family history alone does not prove a hereditary syndrome.
Details
Useful family information
Record cancer types and ages at diagnosis on both sides of the family, together with documented genetic results. Multiple cancers or patterns such as breast and ovarian cancer or early colorectal cancer may raise suspicion, but require contextual assessment.
Before buying a test
Counselling helps select the right test and person to test; starting with an affected relative may be more informative. Tumour testing does not automatically replace inherited-risk testing. Some findings are uncertain, and a negative result may not remove all familial risk.
What a positive result means
A pathogenic inherited variant can increase risk without making cancer inevitable. It may change screening or prevention and guide testing for appropriate relatives. Uncertain results should not alone drive preventive surgery or reassurance.
Related reading: What is tumour next-generation sequencing, and does every cancer patient need it?.