Colonic adenoma patients have higher incidence of hyperplastic polyps on surveillance colonoscopy

OBJECTIVES: To determine the incidence of hyperplastic polyps in patients undergoing surveillance colonoscopy and to compare with the prevalence in individuals undergoing index colonoscopy. PATIENTS AND METHODS: This prospective observational study included patients with index colonoscopy findings of adenomas, adenoma with concomitant hyperplastic polyps and advanced neoplasia who subsequently underwent surveillance colonoscopy. Patient characteristics, indications for colonoscopy, interval between examinations and findings were recorded. These findings were compared with our control group that comprised of patients who underwent index colonoscopy during the same period. RESULTS: Study group consisted of 108 patients (median age 61.5 years) who underwent index colonoscopy for indications including, weight loss, rectal bleeding, altered bowel habits and anaemia. On index colonoscopy, adenomas, adenoma with concomitant hyperplastic polyps and advanced neoplasia were present in 61, 35 and 12 patients, respectively. Surveillance colonoscopy was performed after a mean follow-up period of 29 +/- 17 months. Findings on surveillance examination included hyperplastic polyps in 35 and 57% of patients with past adenomas and adenoma with concomitant hyperplastic polyps, respectively. Control group included 3852 symptomatic patients who had index colonoscopy (median age, 65 years). Hyperplastic polyps, adenomas and advanced neoplasia were found in 155 (4%), 388 (10%) and 60 (1.5%) of patients, respectively. Hyperplastic polyps and adenoma were significantly higher in study group as compared with control group (P >0.5). CONCLUSION: Incidence of hyperplastic polyps is significantly higher on surveillance colonoscopy as compared with the prevalence on index colonoscopy. This may signify a continuous spectrum of biological evolution between hyperplastic polyps and adenomas.