Yield from colonoscopic screening in people with a strong family history of common colorectal cancer.

Background And Aims: People with a strong family history of common (so-called 'sporadic') colorectal cancer are generally advised to undergo colonoscopic screening, but the starting age for this is unclear. An audit was performed to study the age-related yield of screening colonoscopy in this risk group.

Methods: A prospective audit of the outcome of screening colonoscopy was performed on a cohort of 232 people with a strong family history of common colorectal cancer. All were registrants in a familial bowel cancer service solely because of their family medical history. They had no bowel symptoms and no prior endoscopic investigation of the large bowel.

Results: Neoplastic lesions were detected by using colonoscopy in 33 participants. In 27 participants, the major lesion was a small tubular adenoma, four had an advanced adenoma and two had cancer. More neoplastic (P= 0.02) and advanced neoplastic (P= 0.03) lesions were found in those patients aged > or = 50 years. Only one advanced adenoma was detected in a participant below the age of 50 years.

Conclusion: The yield from screening colonoscopy in young people (< 50 years) with a strong family history of common colorectal cancer is low, placing doubt on the need for colonoscopic screening before the age of 50 years.