Hybrid Versus Non-Hybrid Endoscopic Submucosal Dissection for Colorectal Polyps (SHORT-ESD)

Endoscopic submucosal dissection (ESD) permits the en-bloc resection of colorectal lesions irrespective of size. En-bloc resection, as opposed to piecemeal endoscopic mucosal resection (EMR) of colorectal polyps ≥20 mm, provides a more definitive resection specimen for accurate histopathological assessment, and is associated with a low risk for recurrence1,2. Current guidelines from the Japan Gastroenterological Endoscopy Society (JGES), the European Society of Gastrointestinal Endoscopy (ESGE), and the American Gastroenterology Association (AGA), recommend ESD as a preferred strategy for superficial colorectal lesions with suspicion for advanced neoplasia or early cancer (e.g. depressed morphology, advanced surface pattern, nongranular laterally spreading tumor \[LST-NG\], polyps, ≥20 mm in size)3-5. In these cases, ESD procures an ideal pathological specimen for submucosal staging, provides curative intent, and prevents unnecessary surgery for lesions with low risk for lymph node metastasis6 Yet, ESD in the United States and Europe has been primarily restricted to specialized centers for a variety of reasons, notably due to its technical complexity7. Technical difficulty resides primarily in the process of submucosal dissection using endoknives. Maintaining adequate visualization of the dissection plane during ESD is often regarded the rate-limiting step (Figure 1 Non-hybrid ESD). Other factors, including maintaining the endoknife parallel to the dissection plane and accounting for paradoxical scope movements due to patient-related factors (e.g. colon redundancy, peristalsis, breathing movements) represent formidable challenges during colorectal ESD. These technical hurdles can lead to prolonged procedural times and higher risk for adverse events8. Overcoming these barriers is necessary for the safe and widespread adoption of ESD in Western clinical practice. To reduce the technical difficulty of colorectal ESD, several techniques have been introduced, such as the introduction of traction techniques to assist with the exposure and visualization of the dissection plane during ESD8. However, many of these traction techniques require additional devices, second-hand assistance, and have a learning curve of their own9-12. Hence, many of these methods have not been widely adopted. Hybrid ESD is a modified ESD technique that uses snare-assisted resection as part of the procedure7. With hybrid ESD, a circumferential mucosal incision followed by limited submucosal dissection is performed. Following this, a snare is placed around the lesion, slowly closed to allow resection by traversing the submucosal space. The main advantage of this method is that it reduces the need for deep submucosal dissection underneath the center of the lesion, which intuitively would reduce procedural time and risk of adverse events. Furthermore, snare resection is a technique that is familiar to most endoscopists in the West. A recent systematic review and meta-analysis evaluated outcomes between hybrid ESD and conventional ESD for colorectal lesions7. In aggregate, when compared with conventional ESD among over 2000 patients, hybrid ESD was associated with a shorter procedural time (mean difference of 18.5 minutes, p=0.003). The rate of adverse events decreased for hybrid ESD compared with conventional ESD (odds ratio 1.56; p=0.04), but no difference when stratified by perforation rate (odds ratio 1.86; p=0.11) or delayed bleeding (odds ratio 1.15; p=0.7). Conversely, hybrid ESD was associated with a lower rate of en-bloc resection when compared to conventional ESD (odds ratio 0.31; p\<0.001)7. There are several limitations with this data. For one, 14 out of the 16 studies included in this analysis were observational in design. Hence, important factors, such as lesion size, endoscopist experience, type of snare, were not accounted for in most of the studies. Notably, the meta-analysis included studies in which hybrid ESD was used as a rescue therapy after failed conventional ESD, which further complicates the interpretability of the results. Furthermore, only 4 studies originated from the West (Europe) and none from the United States, limiting the generalizability of this technique by US endoscopists. In all, high-quality studies evaluating hybrid ESD for colorectal lesions are needed. This proposed trial will randomize 60 patients with a ≥20 mm large colorectal polyp to either undergo hybrid or non-hybrid ESD. For the primary comparison (hybrid vs non-hybrid ESD), the primary outcome will be procedure time. The study will further examine the safety and efficacy of hybrid ESD compared to non-hybrid ESD and investigate factors that may be associated with resection outcomes. This trial is timely, as ESD has been endorsed in recent years by multiple international and national GI societies. This study will provide information on the feasibility of hybrid ESD as a modified technique that can be more widely adopted in the West. The findings of this trial will therefore help identify a safe and practical ESD technique for large colorectal polyps.