Pretraction-assisted endoscopic submucosal dissection for rectal neuroendocrine tumors: Efficacy and future directions

Abstract

This article comments on a recent study by Guo et al demonstrating that pretraction-assisted endoscopic submucosal dissection (p-ESD) significantly improves treatment outcomes for rectal neuroendocrine tumors. Compared to conventional endoscopic submucosal dissection, p-ESD offers advantages such as shorter dissection time, higher R0 resection rates, and reduced incidence of complications. While acknowledging these encouraging findings, this study highlights key directions for future development: Elucidating the specific mechanisms of pretraction, establishing the generalizability of p-ESD through prospective multicenter studies, and validating its oncological efficacy through long-term follow-up. Addressing these issues is crucial for the broader application and standardization of p-ESD in clinical practice.

Key Words: Endoscopic submucosal dissection; Rectal neuroendocrine tumors; Pretraction; Long-term follow-up; Efficacy; Pretraction-assisted endoscopic submucosal dissection

Core Tip: Pretraction-assisted endoscopic submucosal dissection is a safe and effective therapeutic technique for rectal neuroendocrine tumors. This significantly improves R0 resection rates and reduces the risk of adverse events. Further validation of the efficacy and generalizability of pretraction-assisted endoscopic submucosal dissection requires elucidating its specific mechanisms, conducting prospective multicenter studies, and performing long-term follow-up.

TO THE EDITOR

We read with great interest the original article by Guo et al[1]. This retrospective cohort study evaluated the efficacy of pretraction-assisted endoscopic submucosal dissection (ESD) for the resection of rectal neuroendocrine tumors (NETs). Compared with conventional ESD, pretraction-assisted ESD (p-ESD) significantly shortens the dissection time, improves R0 resection rates, and reduces the risk of intraoperative bleeding and muscularis propria injury. This study highlights an innovative approach for establishing traction before mucosal incision, which represents a significant advancement in traction-assisted ESD. Although these findings are encouraging, a more in-depth examination of several key aspects from an expert’s perspective will help advance their clinical application.

MECHANISTIC ANALYSIS AND TECHNICAL ESSENTIALS OF “PRETRACTION”

The core innovation of the “pretraction” concept lies in establishing traction before submucosal incision[2]. Theoretically, this method enables immediate and sustained exposure of the submucosal layer after an incision, thereby enhancing visibility and improving the safety and efficiency of ESD[3]. These results robustly validate the theoretical advantage. Notably, the p-ESD group did not exhibit muscle layer injury. This finding suggests that the advantages of pretraction may extend beyond enhanced visualization. It is recommended that studies elaborate on the mechanism of p-ESD. For instance, does the initial traction primarily stretch the mucosa and superficial submucosa and effectively “tighten” the dissection plane to reduce unintended deep dissection? Furthermore, this study determined whether a titanium clip closure was performed in the p-ESD group. As this group achieved zero damage to the muscle layer, titanium clips were used for wound closure.

The authors clearly describe the pulley system setup in the article, and the p-ESD procedure is detailed in a previous study[2]. For broader clinical adoption, it is essential to focus on the core clinical value of p-ESD, namely its ability to standardize treatment for rectal NETs by improving R0 resection rates and reducing complications, thereby benefiting a wider range of endoscopists, regardless of their experience level. Providing standardized procedural videos and diagrams in future studies would significantly reduce the learning curve for novice endoscopists, thereby promoting broader adoption of p-ESD.

The pulley system device employed by the authors is suitable for rectal NETs, but may present operational challenges for colonic lesions. Consequently, exploring alternative traction devices for pretraction may offer new avenues for p-ESD development. For instance, the currently developed robotic gripper, which integrates traction with closure, can significantly streamline the procedure[4]. Such instruments with dynamic reclamping capabilities will enhance dissection efficiency and operational convenience, particularly for larger lesions.

THE NECESSITY OF GENERALIZABILITY AND PROSPECTIVE VALIDATION

The authors correctly acknowledge the inherent limitations of their single-center, retrospective study design. All procedures were performed by a single expert endoscopist, effectively controlling operator variability and demonstrating the feasibility and efficacy of p-ESD under expert guidance. However, this also raises an important question regarding generalizability. The pretraction technique requires precise preoperative assessment of traction points, direction, and tension, which requires substantial operator experience. Therefore, the next critical step in validating this technique is to conduct a prospective study involving endoscopists with different levels. Does p-ESD truly simplify procedures for low-volume practitioners, or does it introduce new complexities? We strongly recommend that the authors initiate multicenter prospective studies to address these questions, thereby providing guidance for developing standardized training protocols and determining the optimal clinical scenarios for p-ESD.

LONG-TERM EFFICACY FOLLOW-UP

This study confirmed the superior short-term efficacy of p-ESD, which is particularly impressive, given its 100% R0 resection rates. Furthermore, the authors reported a median follow-up duration of 22 months, during which no tumor recurrence was observed in either group. These preliminary results validate the thoroughness and reliability of p-ESD as a technique. By improving R0 resection rates and reducing complications, p-ESD has the potential to enhance long-term patient outcomes, including increased recurrence-free survival and improved quality of life. However, research indicates that rectal NETs exhibit relatively indolent biological behavior, and their complete natural history may require extended observation periods[5]. Therefore, we anticipate that the authors will conduct long-term follow-up of this cohort to confirm whether the high R0 resection rates achieved by p-ESD translate into demonstrable long-term recurrence-free survival benefits. This would provide more definitive evidence of the oncological efficacy of p-ESD.

CONCLUSION

In summary, this retrospective study has proposed a refined ESD technique specifically tailored for rectal NETs and provided compelling preliminary evidence. The p-ESD technique holds significant promise for standardizing the treatment of rectal NETs and improving patient prognosis through higher R0 resection rates and lower complication rates, which are expected to translate into improved long-term outcomes, such as recurrence-free survival. Future research should include prospective multicenter studies and establish standardized operational protocols to promote the widespread application of this innovative technique.