Mark M, 2015, Journal of Clinical Oncology (Link to abstract)
This retrospective cohort study from MD Anderson evaluated 193 patients with colorectal cancer who underwent genetic counselling over a 5 year period. They identified 35 % of these patients to have an identifiable hereditary cancer syndrome. Whilst patients with a cancer syndrome were more likely to present at earlier stages and have a family history of cancer, 19 % of the hereditary syndromes were found in individuals with no family history.
*Refer ALL adolescents with colorectal cancer for genetic counselling regardless of family history or phenotype!