For each cancer type, between 5 and 10% of cases are attributable to a hereditary form. A tumor is called hereditary when its onset is due to a genetic mutation transmitted by the parents.
Mutations in parents have a 50% chance of being passed on to their children. The latter do not inherit the tumor itself, only the predisposition to develop that tumor more easily than the general population.
Individuals carrying a genetic mutation predisposing to a specific cancer are considered to be at high risk and must undergo appropriate prevention protocols.
Identifying and treating tumors with a familial origin is a challenge that requires special resources and skills. This is why IOV created the Hereditary Tumor and OncoEndocrinology unit, which works in synergy with the Unit of Immunology and Molecular Diagnostics, specializing in the following neoplasms:
- familial colorectal cancer
- hereditary endocrine / neuroendocrine tumors
- hereditary breast and ovary cancer
- familial melanoma
- hereditary kidney cancer
Cancer genetic counseling and genetic testing
Cancer genetic counseling is available for people with suspected hereditary predisposition to develop cancer. Counseling is carried out by a multidisciplinary team that includes:
- a geneticist
- an oncologist and / or appropriate expert specialist
- a psychologist
Patients or healthy individuals who undergo oncogenetic counseling are invited to provide data on their family, on their illness and that of their relatives. After drawing the family tree and an exhaustive analysis of the medical data, the geneticist verifies the presence or absence of criteria to perform a genetic test.
The choice to undergo a genetic test must be made independently and consciously after receiving, during consultation, all the available information on:
- the disease and / or the risk of developing it
- the genetic investigation and its limits
- the risk of illness associated with the test results
- the available preventive and / or therapeutic possibilities
Given the complexity of the topics covered and of the choice to undergo the test and / or undertake specific monitoring / risk reduction, psychological counseling is offered to ensure adequate support and to favor autonomy in decision-making.
After signing an informed consent form, the patient may decide to undergo the test, which requires a blood sample or a buccal swab. Molecular analysis of genes is performed in the Molecular Biology Laboratory of the Hereditary Tumor and Oncoendocrinology Unit.
Results of the genetic test
From the genetic test, it is possible to obtain:
- an informative result (the predisposing mutation is identified);
- a non-informative result (the predisposing mutation is not identified either because it is on a gene not yet known or because it is not identifiable by the currently available analysis);
- a doubtful result, if a gene variant of which the pathogenetic effect is not known is identified.
The result of the test will be communicated in a subsequent consultation session, in which the molecular data will be interpreted and the most appropriate surveillance program and possible risk reduction options will be illustrated. While awaiting the test result, which may take a relatively long time (even longer than 6 months), the patient and family members will be provided with an appropriate surveillance protocol.
Only if the result is informative, can the genetic test be extended to other adult members of the family who wish to do so. In families where a mutation that predisposes to cancer is identified, the family members at risk will be recommended for genetic testing by the patient or family doctor with indications to contact the Hereditary Tumor and Oncoendocrinology Unit.