How accurate is preoperative colonoscopic localization of colonic neoplasia?

Introduction: Preoperative colonoscopic localization for resection of colonic neoplasia, with or without tattooing for guidance, has been extensively used with variable accuracy. Difficulty in intraoperative identification of the lesion may lead to resection of an incorrect segment or to a more extensive resection than originally planned. The aim of this study was to evaluate the accuracy of preoperative colonoscopy in determining the site of the lesion. Methods: A prospectively collected IRB-approved institutional database was retrospectively queried for all consecutive patients who underwent an elective colon resection for neoplasia between 2013 and 2016. Excluded were patients without preoperative colonoscopy reports available for comparison or who underwent emergency surgery. Surgical plan based on preoperative colonoscopic localization with or without tattooing was compared to the final surgery and pathology reports. Results: 203 patients were included [mean age 68 (35–92) years; 102 males (50.2%)]. Preoperative colonoscopy was inaccurate in 16.7% (34 patients) leading to a change in the surgical plan. Patients with transverse or distal lesions were more likely to have a change in final surgical management compared to proximal sided lesions (29.7% vs. 3.9%, respectively; p < 0.001). Only 3.8% of the tattooed lesions could not be identified during surgery. Additional intraoperative colonoscopy was needed in 11 patients (5.5%) to verify exact lesion location. Average length of the resected segment was longer in patients who required a change in surgical plan (26.44 cm vs. 22.47 cm; p = 0.02). Conclusion: Inaccurate preoperative colonoscopic localization led to a change in surgical management in 16.7% of cases, especially in transverse or left sided lesions. Surgeons should consider these findings when planning colonic resections.