Effect of prior biopsy sampling, tattoo placement, and snare sampling on endoscopic resection of large nonpedunculated colorectal lesions

Background: Endoscopic manipulations, including biopsy sampling, tattoo application on the lesion itself, and sampling of the lesion with a polypectomy snare, are frequently performed on large nonpedunculated colorectal lesions >= 20 mm (LNCL) before referral for endoscopic resection. Objective: To assess the effect of prior manipulations on the technical difficulty and recurrence rates of subsequent endoscopic treatment. Design: Retrospective study. Setting: Two referral centers. Patients: Patients with LNCL referred for endoscopic resection. Interventions: Endoscopic resection. Main Outcome Measurement: En-bloc resection rate, rate of successful complete endoscopic resection without the need for ablation of visible residual, recurrence rate on follow-up, independent predictive factors for en-bloc resection, complete resection without ablation of visible residual, and recurrence. Results: A total of 132 lesions was analyzed: 46 lesions without any prior manipulation, 44 with prior biopsy sampling only, and 42 with prior advanced manipulation including tattoo and/or snare sampling. The en-bloc resection rate was 34.8% for nonmanipulated lesions, 15.9% for lesions with prior biopsy sampling, and 4.8% for lesions with prior advanced manipulation (P = .001). Complete endoscopic resection without the need for ablation of visible residual was performed in 93.5% of nonmanipulated lesions, 68.2% of lesions with prior biopsy sampling, and 50% of lesions with prior advanced manipulation (P < .001). Recurrence rates were 7.7%, 40.7%, and 53.8% in the 3 groups (P = .001). In multivariate analysis, prior biopsy sampling was an independent predictor for inability to perform complete resection without ablation of visible residual (odds ratio .24, P < .05) and for recurrence (odds ratio 11.5, P = .004) compared with nonmanipulated lesions. Prior advanced manipulation was an independent predictor for inability to perform en-bloc resection (odds ratio .024, P = .001), for inability to perform complete resection without ablation of visible residual (odds ratio .081, P < .001), and for recurrence (odds ratio 18.8, P = .001). Limitations: Retrospective study. Conclusions: Prior biopsy sampling and advanced manipulation have significant deleterious effects on endoscopic treatment of LNCL.