Is EndoRotor the answer to residual colonic lesions?

In 2024, colorectal cancer is the third leading cause of cancer-related mortality in men and women (1). Early detection and removal of polyps through endoscopic procedures are critical to reducing its incidence and mortality rates. Polypectomy has been shown to significantly reduce the risk of progression to colorectal cancer (2). Conventional endoscopic mucosal resection (CEMR) is the established method for the resection of non-pedunculated colorectal lesions ≥10 mm. However, residual polyps may remain after initial polypectomy, especially after removal of large polyps (>20 mm) and non-en bloc resections (3). Residual neoplasia after CEMR of large colonic lesions has been reported in 10% to 32% of resections (4). Incompletely resected polyps at baseline colonoscopy have been implicated in 10–27% of interval cancers (5). Thus, complete polypectomy without residual adenoma is a key component of a highly effective colorectal cancer prevention program (6). Various strategies and techniques such as underwater EMR (UEMR) (7), endoscopic submucosal dissection (ESD) (8), margin marking (9), tissue ablation (10) and wide-field EMR (11) have been shown to be effective in reducing the risk of residual colonic lesions (RCLs). However, these techniques are not yet universally available and even in the best-case scenario, the incidence of recurrence is not zero. The recurrence varies between 10–32% for conventional EMR (4), decreases to 2% with UEMR (7), and 1.3% with ESD (8).

To detect potential recurrence, the US Multi-Society Task Force on Colorectal Cancer recommends that surveillance colonoscopy should be performed at 6 months after piecemeal resection of adenomas ≥20 mm (12). Otherwise, if a recurrent lesion is identified, a second endoscopic treatment can be attempted. However, residual polyps at the site of previous polypectomy are often fibrotic and non-adherent, making additional resection very challenging (4). Several techniques have been described that could be used for endoscopic treatment of RCL, including repeat CEMR, UEMR, salvage ESD, full thickness resection, and various ablation techniques. These procedures may be used alone or in combination (4,13-15). However, each method has specific limitations for the treatment of RCL (Table 1).

To address these challenges, the EndoRotor (Intercope, Inc., Northbridge, Mass, USA), an endoscopic powered resection (EPR) device, has been developed and tested. The motorized EPR catheter is connected to a power console and can be used at low (1,000 rpm) or high (1,750 rpm) speed, with vacuum set between 50 and 200 mmHg of negative pressure. The catheter is inserted through the working channel and to resect the target tissue, the scope moves back and forth similar to the argon plasma coagulation (APC) catheter (17). This device aims to improve the efficiency and safety of resection of residual or recurrent colonic lesions, especially in scarred areas where traditional methods may be less effective (16). The EndoRotor has several notable advantages. It is a non-thermal resection device, unlike traditional thermal resection methods such as CEMR, ESD, UEMR or APC. Thermal injury to delicate surrounding tissues, post-procedure pain, post-polypectomy syndrome and late thermal adverse events have been described after traditional thermal devices (18). These characteristics allow the use of the EndoRotor in sensitive areas. The presence of scar tissue prevents adequate submucosal lifting, increasing the risk of perforation and incomplete resection. The EndoRotor overcomes these challenges by allowing mechanical debridement of fibrotic tissue without relying on submucosal lifting (19). An essential aspect of any polypectomy is the ability to obtain tissue samples for pathologic examination, which is critical for accurate diagnosis and evaluation of the resected lesion. Unlike purely thermal ablative methods, the EndoRotor allows tissue sampling during resection. Fragments of the specimen are aspirated and collected in a specimen trap attached to the device, facilitating optimal patient management (19).

In this article, Knabe et al. describe the use and results of EPR in the treatment of RCL in an international multicenter prospective study with a substantial number of cases (68 lesions in 65 patients), with a technical success of 98% per protocol and an incidence of 5% of serious adverse events (17). However, some considerations are worth mentioning. First, the mean size of RCLs in this study was 21 mm. RCLs are typically smaller (2.5–5.0 mm) (13). This may reduce the efficacy of the method, but the authors also describe injection into the submucosa prior to EPR, perhaps also because of the large size in their study. However, if the lesion can be elevated, it can also be theoretically resected using the CEMR technique. Another noteworthy aspect is that device failures were reported in 13 of the 45 patients in the intention-to-treat population. Six due to catheter blindness, four due to articulation beyond functional limitations and three due to catheter obstruction. The EndoRotor also has significant disadvantages that must be considered before its use. The catheter requires a minimum working channel of 3.2 mm, which means that conventional gastroscopes cannot be used. The catheter has a certain rigidity and should not be used when the tip of the endoscope is bent more than 60°, as this can lead to catheter failure. Although this does not compromise patient safety, the use of more than one catheter increases procedure costs. Colonoscopy itself can be challenging due to normal anatomical flexures and polyp disposition. EndoRotor may negatively affect or further limit the maneuverability of the colonoscope (17).

As a non-thermal resection, the use of EndoRotor may increase the risk of bleeding during the procedure. In this study, the intraprocedural hemorrhage occurred in only 6.2%, 4.6% of delayed bleeding (3/65) and one perforation (1.5%) (17). Despite the relatively low adverse event rate, it is important to remember that this experience was limited to 68 patients. Therefore, the safety of EPR should be viewed with caution and further results from larger cohorts are necessary.

One reported advantage of EPR, especially when compared to thermal ablation, is the possibility of specimen retrieval for histology. However, some points also need to be addressed. Firstly, despite reports of advanced neoplasia following endoscopic resection of initially benign lesions, this is extremely rare (20). The pathology of the RCL is usually the same as that of the original lesion. Another point is that the fragments obtained by EPR are very small (1–2 mm), which can make analysis difficult for less experienced pathologists. Finally, the EPR could be considered a micropiecemeal resection, which may also be related to the high incidence of persistent lesions at follow-up (46.7%) (17).

Considering the above points, we believe that despite the technical difficulties associated with the use of the EndoRotor, tertiary referral centers should be aware of this option for scarred polyps. In addition to the design improvements promised by the manufacturer, we suggest some other points for optimal usage of this device. Just as Kim et al. (14) showed a lower rate of persistent lesions with UEMR than with CEMR for RCLs, the combination of UEMR with EndoRotor may also be more effective with UEMR than with CEMR, as occurred in this study. Margin marking may also be useful (9). Finally, as in the last European Society of Gastrointestinal Endoscopy recommendation (21), thermal ablation should be used after fragment resection and since EndoRotor is a piecemeal resection, this may also be beneficial in this RCL scenario.

Finally, we suggest randomized clinical trials comparing the different techniques available with the EndoRotor for the treatment of RCLs and even combining the techniques to see which will be the best standard for the removal of these challenging lesions.

Acknowledgments

None.

Footnote

Provenance and Peer Review: This article was commissioned by the editorial office, AME Clinical Trials Review. The article has undergone external peer review.

Peer Review File: Available at https://actr.amegroups.com/article/view/10.21037/actr-24-126/prf

Funding: None.

Conflicts of Interest: All authors have completed the ICMJE uniform disclosure form (available at https://actr.amegroups.com/article/view/10.21037/actr-24-126/coif). F.M.F. reports consulting fees from Boston Scientific, Olympus, and Medtronic. The other authors have no conflicts of interest to declare.

Ethical Statement: The authors are accountable for all aspects of the work in ensuring that questions related to the accuracy or integrity of any part of the work are appropriately investigated and resolved.

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