Predictors of advanced colorectal neoplasia at initial and surveillance colonoscopy after positive screening immunochemical faecal occult blood test.

Background: Characteristics such as gender and lifestyle are not taken in account in colorectal cancer screening and surveillance recommendations.

Aims: To identify factors associated with advanced neoplasia at initial and surveillance colonoscopy.

Methods: In this observational study, 750 individuals with positive faecal occult blood test, aged 50-74 years, underwent a first screening colonoscopy in 2007-2009. We collected anthropometric data as well as data on physical activity, smoking and drinking habits, fruit and vegetable consumption and low-dose aspirin use through a questionnaire.

Results: At initial colonoscopy advanced neoplasia (n=399, 53.2%) was positively associated with age, male gender, smoking and alcohol drinking, and inversely associated with physical activity, fruit and vegetables consumption and long-term use of aspirin. These 7 factors were used to calculate a risk score, ranging from 0 (no unfavourable characteristics) to 7 (all unfavourable characteristics present), which was significantly associated with advanced neoplasia (odds ratio 1.55 for one point increase, P<0.01). Among the 372 adenoma patients who returned for follow-up surveillance colonoscopy, the score remained associated with advanced neoplasia (odds ratio 1.28 for one point increase, P=0.01).

Conclusion: Besides age and gender, modifiable factors such as lifestyle and aspirin use were associated with the risk of advanced neoplasia at initial and surveillance colonoscopy.