Subjects older than 60 years with negative findings on sigmoidoscopy should still undergo colonoscopy.

Background/aims: The objective of this study was to evaluate the impact of age on the prevalence of proximal clinically important lesions in subjects without any rectosigmoid neoplasm.
Methodology: The present study involved 497 patients (aged > or = 50 years old) who underwent a colonoscopy because of abdominal symptoms or positive fecal occult blood test. A proximal colon was defined as one proximal to a sigmoid colon. Clinically important lesions were defined as adenocarcinoma, tubular adenoma > or = 1 cm in diameter, or adenoma with villous histology or high-grade dysplasia.
Results: Of the 497 patients, 83 had clinically important lesions in the proximal colon. Of those 83, 53 patients had no neoplasm in the distal colon or rectum. In patients with no distal neoplasm, the prevalence of proximal clinically important lesions in subjects over 60 years old significantly exceeded that in patients aged 50-60 (39/105 vs. 14/125; P < 0.0001). In patients with distal neoplasm, the prevalence of proximal clinically important lesions in subjects over 60 was similar to that in 50 to 60-year-old subjects (16/119 vs. 14/148; P = 0.406).
Conclusions: Results suggest that subjects older than 60 years old should still undergo a colonoscopy even if they have no neoplasm on sigmoidoscopy.