Predicting advanced proximal colonic neoplasia with screening sigmoidoscopy

Area of Science:

• Gastroenterology
• Oncology
• Preventive Medicine

Background:

• Follow-up colonoscopy indications for distal colonic tubular adenomas (TAs) after screening sigmoidoscopy are not well-defined.
• Identifying patients at higher risk for proximal colonic neoplasia is crucial for optimizing surveillance strategies.

Purpose of the Study:

• To investigate if distal adenoma characteristics (size, number, villous histology), family history, and patient age predict advanced proximal colonic neoplasia.
• To inform personalized screening and surveillance protocols for colorectal cancer.

Main Methods:

• Cross-sectional analysis of 2972 asymptomatic subjects aged 50+ undergoing colonoscopy.
• Data collected from sigmoidoscopy, colonoscopy, and pathology reports between 1994-1995.
• Advanced proximal neoplasia defined as adenocarcinoma or TAs ≥1 cm, with villous features, or severe dysplasia in the proximal colon.

Main Results:

• Prevalence of advanced proximal neoplasia was similar across groups with no distal TAs, small TAs (<1 cm), and large TAs (≥1 cm).
• Patients with distal tubulovillous or villous adenomas had a 12.1% prevalence of advanced proximal neoplasia.
• Distal tubulovillous/villous adenoma (OR 2.30), age ≥65, multiple adenomas, and positive family history were significant predictors of advanced proximal neoplasia; distal adenoma size was not.

Conclusions:

• Advanced proximal neoplasia is prevalent in individuals with and without distal TAs.
• Individuals with advanced distal adenoma histology and those aged 65+ face increased risk.
• Age-specific screening protocols, including sigmoidoscopy from 50-55 and colonoscopy after 65, may be warranted.