Endoscopic submucosal dissection (ESD) is increasingly used for en bloc resection of advanced colorectal neoplasia. This technique allows curative resection of advanced pathologies, such as high-grade dysplasia and superficial submucosal invasive cancers, and has lower recurrence rates than piecemeal endoscopic mucosal resection. However, the lengthy duration of these procedures, steep learning curve, and risk of significant adverse events have impacted their uptake in Western countries.1,2
Improvements in technology and techniques are especially of significant benefit to Western endoscopists in aiding the achievement of safe and effective ESD in the colorectum. In populations with low prevalence of early gastric cancer, endoscopists are confined to the early practice of ESD in the rectum and distal colon. Traction-assisted ESD is increasingly described as a helpful technique.3,4 Traction and counter traction devices are more available but are not entirely without challenges. Completing difficult lesions with hybrid techniques involving dissection followed by snaring to complete the resection, has been well described. However, successful en bloc resection with this technique is also dependent on the endoscopist’s skill and is determined by the presence of fibrosis and ability to visualize adequately while snaring.5 Similarly, performing underwater ESD with saline infusion has been described as a relatively newer technique.6 This may be particularly helpful to novices in differentiating the submucosal plane and reducing the risk of injury to the muscle layer. Furthermore, this technique is suggested to aid experts in situations with recurrent lesions or fibrosis.7 Many different ESD accessories and newer types of knives have been added to our therapeutic armament. Many of these now have the combined capabilities of injection, cutting, and dissection with electrocautery, as well as hemostatic abilities. Whilst they are far more evolved than the original versions, intraprocedural changes to accessories are still required for incremental submucosal injections and hemostasis. Procedural duration is definitely incremented by these necessary changes. Non-experts are also more likely to require these and not having achieved the confidence of experts in always distinguishing the submucosal plane, be more reliant on frequent submucosal injectates.
A new knife that allows a high-pressure waterjet function simultaneously with cutting or dissection has previously been described.8 In a pilot study, Zhou et al.9 described the benefits of adopting the hybrid knife technique in a subgroup of patients with gastric neoplasia. In a randomized controlled trial comparing conventional ESD to waterjet-assisted ESD, the mean procedure time was established to be significantly shorter in the waterjet-assisted ESD group than in the other. In addition, changes in accessories was less frequently required. However, there were no significant differences in R0 resection, adverse events, or recurrence rates on follow-up. In the current issue of Clinical Endoscopy, Cecinato et al.10 describe the first large series comparing conventional ESD to waterjet-assisted ESD in the colorectum. A retrospective series of 123 waterjet-assisted ESD procedures performed in a tertiary center over seven years was analyzed. This study excluded patients with recurrent lesions and those with fibrosis and dysplasia associated with inflammatory bowel disease. In their series compared to 50 conventional ESD during the same period, en bloc resection rates are suggested to be higher (91.4%) with the waterjet-assisted technique. Interestingly, complete resection rates, curative resections, speed of procedure, and adverse events were similar between the two groups. It is pertinent to note that the waterjet-assisted technique was used for far more lesions in the rectum and lesions with recurrence or fibrosis were treated using the conventional technique. Nevertheless, this study highlights the many potential benefits of a newer ESD technique using the hybrid knife for colorectal neoplasia. A well-designed randomized controlled trial may further elaborate on the subgroups of lesions that may be best managed with this approach.