Higher adenoma recurrence rate after left- versus right-sided colectomy for colon cancer

Background Patients with history of colonic resection for cancer have an increased risk of the development of metachronous malignant and premalignant lesions. Scanty data are reported on detection rates of premalignant lesions during colonoscopy surveillance in this setting. Objective To assess the risk of metachronous precancerous lesions developing in patients with previous colonic surgery for cancer according to the resection type. Design Retrospective study. Setting Two academic centers in Italy. Patients A total of 441 patients; 256 with previous left-sided colectomy (LCR) (LCR group) and 185 with previous right-sided colectomy (RCR) (RCR group). Interventions Second surveillance colonoscopy. Main Outcome Measurements Polyp and adenoma detection rates. Results At least 1 adenoma was diagnosed in 76 of 256 patients (30% adenoma detection rate) and in 35 of 185 patients (19% adenoma detection rate) in the LCR and RCR groups, respectively (P =.014), yielding an odds ratio of 1.83 (95% confidence interval, 1.16-2.89). Corresponding figures for the polyp detection rate were 39% and 25%, respectively (P =.002; odds ratio 1.97; 95% confidence interval, 1.30-3.00). Limitations Retrospective study with colonoscopy baseline information missing. Conclusions Patients who have undergone LCR are at higher risk of the development of adenomas than those who have undergone RCR. If this result is confirmed by large prospective studies, surveillance programs could be targeted according to the type of colonic resection, with longer intervals for patients with previous RCR compared with LCR.