Introduction
Piecemeal endoscopic mucosal resection (pEMR) is the preferred treatment for large non-pedunculated colorectal polyps (LNPCPs)[1,2]. A major limitation of pEMR is residual or recurrent adenoma (RRA), which was reported to in 15%-30% of cases at first surveillance colonoscopy (SC1)[3], performed 3-6 months after the index procedure, but is reduced to the range of 3%-5% by applying ablative measures to the post-EMR resection margin[4].
Aims & Methods
This study aimed to evaluate the effects of late SC1 on RRA.
This is an analysis of a prospectively collected cohort of adult patients referred for pEMR at two academic centers in Israel, from 2016 to 2023. We included all patients who underwent pEMR of LNCPCs and completed SC1.
We compared outcomes between patients who completed early SC1 at 3-6 months following the index procedure with patients who completed late SC1 later than 6 months. All procedures and surveillance colonoscopies were performed by experienced endoscopists trained in pEMR using high-definition scopes. EMR was followed by thermal ablation of the entire mucosal defect margin with snare soft tip coagulation, as previously described[4].
Scar evaluation at SC1 was performed with high-definition white light and chromoendoscopy. Our primary endpoint was RRA at SC1.
Analyses were performed per lesion. We compared baseline parameters and outcome rates between groups, and performed multivariate analysis to assess the adjusted association of months to SC1 with RRA.
Results
We analyzed 516 lesions that underwent index pEMR resection and subsequent SC1. Baseline parameters and recurrence rates are presented in Table 1. The early SC1 group (n=371) underwent SC1 at a mean of 5.1 months versus a mean of 11.1 months in the late SC1 group (p<0.01; Table 1). Polyp size in the early SC1 group was significantly larger than that in the late SC1 group (mean size 35.9 mm [SD 13.9] vs. 32.1 mm [SD 12.4], p<0.01; Table 1). The distribution of lesion location, granularity differed between the groups (Table 1). However, there were no significant differences in lesion Paris classification or rates of high grade dysplasia (Table 1).
We found no statistically significant difference in the rate of recurrence at SC1 between the two groups (6.3% in the standard group versus 4.8% in the delayed group, p=0.64). Additionally, a sub-analysis comparing the early SC1 group to patients with very late SC1 (>12 months – mean time to SC1 17.9 (SD [5.4] months) and did not reveal significant difference in recurrence at SC1 (6.2% in the early SC1 vs 6.3% in the very late group, p=1).
Multivariate analysis, adjusted for lesion size, location, and high-grade dysplasia, showed that time to SC1 was not significantly associated with RRA (odds ratio 1.05, 95% confidence interval 0.98-1.13).
TABLE 1. Comparison of baseline variables and outcome between the early and late SC1.
| | Early SC1 (n=371) | Late SC1 (n=145) | P value |
| Time to SC1, months | 5.1 (1.1) | 11.1 (5.6) | <0.01 |
| Age, years | 65.4 (10.4) | 68.0 (10.2) | 0.01 |
| Female, n (%) | 168 (45.4) | 51 (35.2) | 0.05 |
| Lesion Size, mm | 35.9 (13.9) | 32.1 (12.4) | <0.01 |
| Distal location, n (%) | 111 (29.9) | 29 (20.0) | 0.03 |
| Granular morphology, n (%) | 230 (63.7) | 74 (53.2) | 0.04 |
| Paris IIb/IIc/III, n (%) | 39 (10.5) | 15 (10.3) | 1.00 |
| High grade dysplasia, n (%) | 97 (26.1) | 33 (22.8) | 0.49 |
| Recurrence at SC1, n (%) | 23 (6.2) | 7 (4.8) | 0.70 |
SC1, First surveillance colonoscopy
Conclusion
Late SC1 is not associated with an increased RRA. Hence, we suggest that high-quality pEMR with margin ablation may alleviate the need for early SC1, thereby reducing healthcare and patient burdens. Further interventional studies are required.
References
[1] Ferlitsch M, Moss A, Hassan C, et al. Colorectal polypectomy and endoscopic mucosal resection (EMR): European Society of Gastrointestinal Endoscopy (ESGE) Clinical Guideline. Endoscopy 2017; 49: 270–297. doi:10.1055/S-0043-102569/ID/JR15335-1/BIB
[2] Shaukat A, Kaltenbach T, Dominitz JA, et al. Endoscopic Recognition and Management Strategies for Malignant Colorectal Polyps: Recommendations of the US Multi-Society Task Force on Colorectal Cancer. Gastroenterology 2020; 159: 1916-1934.e2. doi:10.1053/j.gastro.2020.08.050
[3] Belderbos TDG, Leenders M, Moons LMG, et al. Local recurrence after endoscopic mucosal resection of nonpedunculated colorectal lesions: Systematic review and meta-analysis. Endoscopy 2014; 46: 388–400. doi:10.1055/S-0034-1364970/ID/JR910-7/BIB
[4] Klein A, Tate DJ, Jayasekeran V, et al. Thermal Ablation of Mucosal Defect Margins Reduces Adenoma Recurrence After Colonic Endoscopic Mucosal Resection. Gastroenterology 2019; 156: 604-613.e3. doi:10.1053/j.gastro.2018.10.003
Disclosure
The authors report no conflict of interests