Endoscopic Mucosal Resection for Colonic Mucosal Neoplasia and Evaluation of Long-Term Recurrence

A Single-Center Experience of 500 Cases

Saeed Ali, MD; Neelam Khetpal, MD; Evgeny Idrisov, MD; Asad Ur Rahman, MD; Sameen Khalid, MD; Yuan Du, MS; Udayakumar Navaneethan, MD; Shyam Varadarajulu, MD; Robert Hawes, MD; Muhammad Khalid Hasan, MD

Disclosures

South Med J. 2021;114(4):199-206. 

In This Article

Discussion

In our study, the recurrence rate of 21.8% at SC1 with a mean lesion size of approximately 39 mm is in line with previous reports.[11,23,24,34] Several methods have been reported to reduce recurrence rates, including prophylactically ablating resection margins by the application of snare tip coagulation;[35] however, we did not prophylactically ablate tissue at resection margins because of a lack of strong evidence. Other possible ways to decrease the rate of recurrence could be the use of high-definition scopes to differentiate between abnormal and normal mucosa, facilitating complete snare excision. Modifications of the EMR, such as the snare used, the resection technique, and the submucosal injection solution may help reduce the risk of recurrence, but additional prospective studies are needed to verify these hypotheses.[36,37]

Our EMR perforation rate of 0.2% is in line with rates previously reported, of 0% to 1.3%.[38] Postprocedural abdominal pain can develop in patients undergoing endoscopic mucosal resection of large colorectal polyps.[37] These patients should be examined for clinical signs of peritonism to rule out serositis or perforation. Patients with persistent pain require imaging studies, preferably computed tomography of the abdomen and pelvis. Other causes of pain include excessive air insufflation, postpolypectomy syndrome, and transmural fluid injection; therefore, the use of carbon dioxide insufflation is recommended for longer EMR procedures.[10] It is important, however, to note that some of the postprocedural complications we report in our study, especially delayed bleeding and self-limiting abdominal pain, may have been underreported as a result of the nature of our referral-based practice (ie, the majority of patients were studied by their referring physicians for further management).

The area of previous resection and scar tissue should be carefully inspected with high-definition white light and NBI at SC for RRA. A large prospective study has shown that a good optical examination using a combination of high-definition white light and NBI can optically predict recurrent adenomas with a high negative predictive value (97%–100%), thereby avoiding the need to biopsy every EMR scar and reducing the cost of the procedure.[39] In a few individuals, the EMR scar may demonstrate a nonspecific focal tissue prominence with a concerning pit pattern. In our practice of such cases, we biopsied the site and resected the abnormal-appearing tissue. If it was not resectable by snare, then the abnormal-appearing tissue was resected and avulsed with cold biopsy forceps, and the site was ablated with snare tip coagulation. Treating suspicious areas after taking biopsies potentially saves repeating colonoscopy in cases in which the biopsy would be abnormal, thereby minimizing cost and burden on the healthcare system; therefore, in suspicious cases, endoscopic resection and/or ablation may be the preferred option.

In our study, the risk factor associated with early recurrence was identified as lesion size >40 mm. This finding is comparable to previously reported studies.[24,34] Increased lesion size has the potential of hiding residual tissue within or at the margin of the EMR defect, thereby increasing the risk of recurrence. Such larger lesions may be considered for ESD, if such expertise is available, because it is associated with a low risk of recurrence.[40,41] Intraprocedural bleeding and high-grade dysplasia, contrary to previous studies, were not associated with recurrence in our study.

One of the interesting findings in our study was the presence of the "late recurrence" of 9.8% after a previous negative SC1. This finding also has been reported by Knabe et al, where late recurrence was reported in 16.3% of cases.[42] One of the reasons for the high rate of late recurrence is likely related to low follow-up rate owing to the nature of our practice, which has been highlighted as a limitation of this study. Although the use of high-definition white light and NBI has been reported by the Evaluation Study of Congestive Heart Failure and Pulmonary Artery Catheterization Effectiveness (ESCAPE) trial to exclude abnormal tissue with a negative predictive value of 97% to 100%,[39] the finding of late recurrence may suggest that although a normal SC1 is reassuring, SC2 cannot be abandoned. In our study, all of the patients who came for SC1 and SC2 were both performed by the index EMR proceduralist, eliminating interrater reliability issues. Given the nature of our practice, however, a large number of SC2s were performed by the referring endoscopist for the convenience of the patients.

Although our study had a reasonably large number of cases for a single center and the results are comparable to those of other studies, it has some limitations as well. First, this is a retrospective longitudinal study as opposed to a prospective study. Second, we practice in a tertiary care referral center, where most patients are referred by other providers. As such, some of the late complications may not have been captured because most of the patients were studied by their local gastroenterologist (reporting bias). Third, we had a low follow-up rate at 16 to 18 months (SC2), probably because of the nature of our practice, as mentioned earlier. Fourth, longer-term follow-up (3–5 years) would be more helpful in assessing long-term outcomes.[24] Lastly, our study suffers from the lack of data regarding previous manipulations of LSLs by referring gastroenterologists. Previous endoscopic manipulations correlate with the recurrence rate,[43] and this information was not available for all of the patients.

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