Almost 2% of patients younger than 50 undergoing colonoscopy at a major Queensland hospital were diagnosed with colorectal cancer, double the rate identified in other studies of younger patients, researchers say.

Australian bowel cancer screening guidelines recommend two-yearly faecal occult blood testing from the age of 50 until 74 but Gold Coast University Hospital researchers say this advice might need review, given emerging evidence of increasing incidence at younger ages.

In their retrospective cohort study, the group reviewed 557 patients aged between 30 and 50 years who had a colonoscopy at Gold Coast Hospital and Health Service between 2013 and 2017.  

Some 45% of the patients underwent polypectomy with 11 (1.9%) being later diagnosed with colorectal cancer. All of them had experienced symptoms and most were stage 3 or 4 at the time of diagnosis.