IMPROVING ENDOSCOPIC ASSESSMENT AND MANAGEMENT OF LARGE NON-PEDUNCOLATED COLORECTAL LESIONS IN A WESTERN CENTER OVER 10 YEARS: LESSONS LEARNT AND IMPACT ON PATIENTS’ OUTCOMES

Aims Outcomes of endoscopic management of large colorectal (CR) non-pedunculated lesions (LNPLs) are still under evaluation, especially in Western settings. We analysed the clinical impact of changes in LNPLs’ management over the last decade in a European center.

Methods All consecutive sessile/laterally spreading (LST) LNPLs ≥20mm endoscopically assessed between 2008-2019 were retrospectively included. Lesions’, patients’ and resections’ characteristics were compared among clinically relevant subgroups. Multivariate logistic regression (for predictors of submucosal invasion [SMI] and recurrence), Kaplan-Meier curves and ROC curves (for temporal cut-offs in trends analyses) were used.

Results 395 LNPLs were included (30mm[IQR 20-40]; SMI=9.6%; primary endoscopic resection [ER]=88.4%). SMI risk was associated to lesion morphologies (from 1.9% of granular-homogeneous to 35% of non-granular-pseudodepressed LSTs; p< 0.0001), dimensions (≥40mm OR=2.9[1.5-5.8]) and location (distal to splenic flexure OR=2.3[1.2-4.6]). However, at multivariate logistic regression, only the presence of pseudo-depression (OR=4.6[1.1-19.7]) and a JNET classification 2b/3 (OR=51.8[12.5-215.5]) independently predicted SMI beyond other factors.

After complete ER, the involvement of ileocecal valve/dentate line, a piece-meal resection and a high-grade dysplasia independently predicted recurrence.

5-years’ Recurrence-free, Surgery-free and Cancer-free survivals were 77.5%, 98.6% and 100%, with 93.8% recurrences endoscopically managed and no death attributable to ER or colorectal cancer (versus 3.4% primary surgery mortality).

ROC curves identified the period ≥2015 (following educational interventions on pre-resective lesion assessment and the introduction of Endoscopic Submucosal Dissection [ESD]) as associated with improved lesions’ characterization, increased en-bloc resection of SMI lesions (87.5% vs 37.5%; p=0.0455), reduced primary surgery (7.5% vs 16.7%; p=0.0072), primary surgical referral of benign lesions (5.1% vs 14.8%; p=0.0019), and recurrences (15.5% vs 27.5%. p=0.0347).

Conclusions ESD introduction and educational interventions allowed ER of more complex lesions, offset by increased complementary surgery for incomplete resections or advanced histology. Notwithstanding, they have overall reduced surgery demand and increased appropriateness and safety of LNPLs’ management in our center.