While most cases of cancer are sporadic, there are subsets of cancers that can be attributed to a hereditary etiology. Family history is still the gold standard in initial assessment for heritable conditions.
In general, suspicion of a hereditary cancer syndrome should be raised if:
- There are multiple family members with cancer
- Cancers occur on the same side of family
- Cancer diagnoses occur at a younger than expected age
- Several generations are affected (demonstrating an autosomal dominant pattern – typical of most hereditary cancer syndromes)
- Clustering of certain types of cancers is present
- Multiple primary cancers are diagnosed in the same individual
5-10% of cases of colorectal cancer (CRC) are hereditary. Lynch syndrome (LS), also known as Hereditary Non-Polyposis Colorectal Cancer (HNPCC), is the most common hereditary CRC predisposition syndrome. It is an autosomal dominant condition that causes a significant increased lifetime risk of CRC and endometrial cancer in addition to other cancers. Individuals suspected of having LS should be referred for a genetic consultation and consideration of genetic testing.
Screening, surveillance and management of CRC and other cancers should be guided by genetic test results and/or family/personal history. Studies show that conversations between patients and their health care providers are the strongest drivers of screening participation.
Are you asking the right questions and identifying your patients who may be at risk of hereditary cancer? Do you know how and where to refer those patients who may benefit from referral to genetics?
Genetics Education Canada – Knowledge Organization (GEC-KO) is a genetics education program funded by the Children’s Hospital of Eastern Ontario (CHEO) with in-kind support from Mount Sinai Hospital in Toronto. GEC-KO is dedicated to the development, collection, dissemination and evaluation of genetics educational materials for health care providers, especially primary care providers.
The GEC-KO website at www.geneticseducation.ca contains educational resources and point of care tools designed for primary care providers. These are intended to facilitate integration of genomic medicine into practice. Additionally, the website helps you to identify your nearest genetics centre and find the information you need to connect with your local genetics specialist and laboratory.
Article written by: Shawna Morrison, Certified Genetic Counsellor – CHEO, Program Manager for GEC-KO