Protection from right- and left-sided colorectal neoplasms after colonoscopy: population-based study

Area of Science:

• Gastroenterology
• Oncology
• Preventive Medicine

Background:

• Colonoscopy is crucial for colorectal cancer (CRC) detection and prevention.
• Evidence on colonoscopy's protective effect by anatomical site in community settings is limited.

Purpose of the Study:

• To evaluate the association between previous colonoscopy and advanced colorectal neoplasms.
• To determine if this association varies by tumor location.

Main Methods:

• Cross-sectional study of 3287 participants aged 55+ undergoing screening colonoscopy in Germany.
• Prevalence of advanced neoplasms assessed via colonoscopy and histology.
• Log-binomial regression adjusted for confounders to analyze previous colonoscopy history.

Main Results:

• Advanced neoplasms found in 11.4% (no prior colonoscopy) vs. 6.1% (prior colonoscopy within 10 years).
• Previous colonoscopy was associated with a 48% overall reduction in advanced neoplasms (PR=0.52).
• Significant reductions observed for left-sided neoplasms (sigmoid colon, rectum), but not right-sided ones.

Conclusions:

• Colonoscopy strongly reduces left-sided advanced colorectal neoplasms within a decade.
• No significant reduction in right-sided advanced neoplasms was observed.
• Findings highlight colonoscopy's effectiveness for left-sided CRC prevention in community settings.