Outcomes of endoscopic resection of large colorectal lesions subjected to prior failed resection or substantial manipulation.

Purpose: Injudicious attempts at resection and extensive sampling of large colorectal adenomas prior to referral for endoscopic resection (ER) are common. This has deleterious effects, but little is known about the outcomes following ER. We retrospectively analysed the outcomes of ER of large adenomas previously subjected to substantial manipulation.
Method: ER of large (≥ 2 cm) colorectal adenomas were grouped according to level of manipulation: prior attempted resection, heavy manipulation (≥ six biopsies or tattoo under lesion) or minimal manipulation (< six biopsies). Outcomes were compared between groups. Independent predictors of outcomes were identified using multiple logistic regression.
Results: Five hundred forty-two lesions (mean size 53.7 mm) were included. Two hundred sixty-five (49%) had been subjected to prior attempted resection or heavy manipulation, 151 (28%) to minimal manipulation, and 126 (23%) were not previously manipulated. ESD techniques were used more frequently than EMR after substantial manipulation. There were no differences in initial success of ER (99%, 98%, 98%, p = 0.71). Prior attempted resection was independently associated with recurrence (OR 2.2, 95% CI 1.1-4.5, p = 0.03) and negatively associated with en bloc resection (OR 0.29, 95% CI 0.1-0.7, p = 0.004). Regardless of level of prior manipulation, there were no differences in sustained endoscopic cure with > 95% of patients overall free from recurrence and avoiding surgery at last follow-up.
Conclusion: There is a substantial burden of injudicious lesion manipulation before referral, which makes recurrence more likely and en bloc resection less likely. However, with appropriate expertise, sustained successful endoscopic treatment is achievable for the vast majority of patients treated in a specialist unit.