Cancer Family Clinics | A Brief Introduction July 17, 2007Posted by ramunas in cancer genetics, familial cancer, hereditary cancer.
Clinical cancer genetics is very new and rapidly expanding field – its more mainstream beginning could be dated back to 1994, when BRCA1, an early onset breast-ovarian cancer gene, was cloned. Now the demand for cancer risk assessment based on the estimation of genetic component of cancer risk for particular individual is increasing rapidly. Cancer patients now constitute more than half of all referrals to clinical geneticists.
This led to the development of cancer family clinics/familial cancer centers, specializing in the management of families at risk of hereditary cancer. The individuals at increased risk of cancer need both genetic and oncologic advice (as well as psychological support).
Since only 5-10% of all solid cancers are hereditary (and c.a. 30% could be familial) therefore a selection based on family history must be performed for individual patients cases. For example, in United Knigdom there are strict referral (and management) guidelines for familial breast cancer, so called NICE guidelines (by National Institute For Health and Clinical Excellencees).
A general guidelines for referral to clinical cancer geneticists are summarized bellow:
- Cancers should be on the one side of a family (either the mother’s or father’s side)
- Two or more rare cancers in the same individual or close relatives (e.g. sarcomas, brain tumors, leukemias, adrenal tumors – features suggestive of Li Fraumeni syndrome)
- Cancer in the context of an associated syndrome (e.g. glioma in neurofibromatosis type 1 (NF1), melanoma (skin cancer) in dysplastic naevus (Gorlin) syndrome)
- Clustering of common cancers or specific tumor pattern, suggesting particular cancer predisposition syndrome (3-2-1): a) three or more cancer of the same type/related types in close relatives (e.g. breast/ovarian/endometrium/colon/prostate); b) two cancers of the same type/related types in close relatives if diagnosed before age 50 or at any age for relatively rare cancers (e.g. ovarian or small bowel); c) one first-degree relative with one of the common cancers diagnosed before age 40 (or if prostate – before 55) (modified from Ponder et al.)
However, for some populations or regions where common founder mutations are present, these guidelines are more relaxed – it could be reasonable to test the diagnosed cancer cases unselected for a family history.Patients are referred by general practitioners (GP) from primary care sector, oncologists (secondary care) or are self-referred.
An important principle – a genetic testing is initiated for affected relative, cause the chances to detect a mutation are higher.
In conclusion: ideally cancer genetic services should be set up with stuff trained in both genetics and oncology and havea good links with molecular genetics laboratory (certified or accredited) . It should also incorporate the use of national or international management guidelines, audit and quality assurance.