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Total Colonoscopy in Patients with Polyps in the Proctosigmoid Region

Abstract: We conducted a prospective study of the general population in Taiwan to determine how many patients with polyps in the proctosigmoid region would have synchronous polyps in the proximal colon. The pathology and the number of proctosigmoid polyps as well as the benefits of subsequent colonoscopy were taken into account. Proctosigmoid polyps were identified in 261 of 2746 asymptomatic patients by 60 cm sigmoidoscopy, yeilding a 9.5% (male: 11.0%; female: 5.0%) prevalence rate. Subsequent total colonoscopy combined with polypectomy was completed in 205 patients (152 males; 53 females) eligible for analysis. In all, 353 polyps were removed for pathological verification at colonoscopy. The mean size of adenomatous polyps was 6.2 mm and that of hyperplastic polyps 3.2mm (p<0.05). Five mucosal cancers as well as one submucosal cancer were identified, and one of the mucosal cancers was beyond the range of the prior 60 cm sigmoidoscopy. Of these 205 patients, 63 (31%) were found to have at least one proximal polyp. The prevalences of synchronous proximal colon polyps were 23%, 42% and 77% for the 1‐polyp, 2‐polyp and β2‐polyp groups in the proctosigmoid region, respectively. When the pathology of the proctosigmoid polyps was taken into account, it was found that 42% of patients with adenomatous polyps in the proctosigmoid region had proximal polyps, compared with 10% of those with distal hyperplastic polyps and 8% of those with other findings (p<0.05). The present study suggests that all polyps, of all sizes, found at sigmoidoscopy merit pathological verification. Furthermore, colonoscopy should be reserved for patients proved to have adenomatous or multiple polyps in the proctosigmoid region.