Central vascular ligation and complete mesocolon excision vs D3 lymphadenectomy: Standardization of surgical technique

Abstract

Surgical advancements have transformed colorectal cancer treatment, with complete mesocolic excision (CME) becoming a crucial method to guarantee oncological safety and effectiveness. The article by Yadav emphasized the significance of CME in attaining optimal resection margins, thorough lymph node dissection, and enhanced long-term survival rates. The adjunctive function of D3 lymphadenectomy, emphasizing the clearance of lymphatic drainage along the supplying vessels, was also addressed. CME with central vascular ligation, based on the principles of total mesorectal excision for rectal cancer, entails en bloc tumor resection and precise dissection along the embryological planes, thus diminishing recurrence and improving survival rates. The viability and safety of minimally invasive techniques, such as laparoscopic CME, have been confirmed; however, technical difficulties remain owing to the intricate vascular anatomy. Robotic-assisted surgery presents potential benefits, including accurate lymphatic dissection and intracorporeal anastomosis. However, evidence demonstrating its superiority over laparoscopic techniques is scarce owing to high costs and prolonged duration. This study promotes the global standardization of CME as an essential element of modern colorectal cancer surgery. CME epitomizes contemporary oncological practices, requiring widespread adoption to achieve superiority in colon cancer management.

Key Words: Laparoscopy; Mesocolon; Colonic neoplasm; Lymph node; Surgical technique

Core Tip: In this recently published manuscript, Yadav emphasized the complementary role of D3 lymphadenectomy, which enhances lymphatic drainage clearance, aligning with the goal of complete mesocolic excision (CME) to achieve R0 resection. The authors advocated for the global standardization of CME and its integration into surgical training to ensure equitable access and improved outcomes in patients with colon cancer. This underscores the role of CME as a cornerstone of modern oncological surgery, which is essential for achieving excellent colorectal cancer treatment.

TO THE EDITOR

Surgical advancements in the evolving field of colorectal cancer treatment have consistently demonstrated their significance in improving patient outcomes. For example, complete mesocolic excision (CME) is a pivotal technique with redefined oncological safety and efficacy. The recent article authored by Yadav[1] and published in World Journal of Gastrointestinal Surgery, effectively emphasizes the pivotal significance of CME with D3 lymphadenectomy for attaining optimal resection margins and enhancing long-term survival rates in patients with colon cancer. The discourse on D3 lymphadenectomy is equally compelling, as it enhances CME by addressing lymphatic drainage along the principal feeding vessels. The techniques prioritize the common objective of achieving R0 resection while optimizing lymph node yield. The present study reconciles these two methodologies and demonstrates how CME and D3 dissection collaborate to yield enhanced oncological results.

The primary principle of colon cancer surgery is the removal of primary tumors and achievement of adequate surgical margins and locoregional lymph node dissection (Figure 1). CME with central vascular ligation (CVL) has been introduced as a treatment for colonic cancer, based on the concept of complete mesorectal excision for rectal cancer, which has resulted in a higher 5-year survival rate and a reduced recurrence rate[2-4]. Similar to the notion of total mesorectal excision, this technique entails the en bloc resection of the tumor and its surrounding soft tissues by sharply dissecting the visceral plane from the parietal fascia layer, as well as the entire regional mesocolon, as a singular and intact structure[5]. This surgical model offers reduced local recurrence and improved survival rates compared with conventional colectomy[3,6].

Figure 1 Open D3 right hemicolectomy. A: Intraoperative view following completion of open right hemicolectomy; B: Specimen examination of reduced-port robotic right hemicolectomy with D3 lymphadenectomy for an ascending colon carcinoma.

Some researchers in the field of surgery have introduced an equivalent lymphadenectomy principle that depends on tumor location and extent and defined the procedure as “modified CME with CVL”[7]. For malignancies that are in the early stages of development, the Japanese Society for Cancer of the Colon and Rectum suggests D2 resection, while D3 resection is recommended for more advanced disease[8]. Regarding the current lack of consensus on the precise boundaries in D2 vs D3 dissection, we acknowledge that this ambiguity arises from variations in surgical guidelines and practices across institutions and regions. As noted in our manuscript, the Japanese Society for Cancer of the Colon and Rectum defines D2 resection as the removal of pericolonic and regional lymph nodes and D3 dissection as the removal of lymph nodes along with the principal feeding vessels. This definition aligns with the broader goals of CME, which emphasize en bloc tumor resection with CME to optimize oncological outcomes. However, the integration of CME with D3 dissection remains under discussion. CME aims to achieve intact mesocolic resection along the embryological plane, ensuring comprehensive lymph node retrieval. In contrast, D3 dissection prioritizes systematic lymphadenectomy along the superior mesenteric vessels. Although these techniques share common oncological principles, their overlap and differentiation require further clarification. Despite the ongoing debate regarding the surgical extent of D3 lymphadenectomy and CME, we are of the opinion that these surgical techniques exhibit comparable oncological safety.

The feasibility and safety of the former have been demonstrated in numerous trials that compare standard laparoscopic and open CME for right-sided colon cancer. These trials have yielded satisfactory oncologic outcomes[9]. However, the execution of minimally invasive CME with CVL for right-sided colon cancer continues to be a difficult task. The feasibility and safety of the laparoscopic method were demonstrated in numerous studies that compared conventional laparoscopic surgery with open CME for right-sided colon cancer, resulting in acceptable oncologic outcomes[10-12]. Nevertheless, the minimally invasive approach to CME and CVL for right-sided colon cancer is difficult due to the complex variable vascular anatomy of the right colon and the technical limitations of laparoscopic instruments. Laparoscopic dissection of the lymph nodes surrounding the superior mesenteric vessels is particularly problematic.

Despite reports comparing the outcomes of laparoscopic CME and CVL, the overall adoption rate of laparoscopic procedures remains low. The intrinsic limitations of laparoscopic surgery were addressed by the development of a surgical robotic system, which was subsequently implemented in the colorectal domain to address the challenges associated with laparoscopic rectal cancer surgery in a constricted pelvic (Figure 2). However, it remains uncertain whether robotic surgery offers substantial clinical advantages over laparoscopic surgery in the treatment of colonic malignancy[13-17]. Robotic colectomy for right-sided colon cancer may provide several advantages. First, it facilitates secure and accurate lymphatic dissection along the superior mesenteric trunk. Second, this method facilitated appropriate mesocolic resection with improved visibility and consistent traction.

Figure 2 Intraoperative view of a robotic right hemicolectomy. A: Exposure of the distal segment of the duodenum and the pancreatic head; B: Sharp dissection between the peritoneal cavity and the mesocolon within the retroperitoneal space; C: Ligation of the ileocolic vessels using the wristed robotic advanced bipolar energy device; D: Dissection of the middle colic vessels.

Intracorporeal anastomosis was ultimately made feasible and secure by the robotic technique. Nevertheless, there is insufficient evidence to support the claim that robotic CME and CVL outperform laparoscopic surgery in terms of clinical and oncological outcomes. Park et al[18] conducted a randomized clinical trial to compare the clinical and long-term outcomes of robot-assisted and conventional laparoscopic right colectomy with CME and CVL. They found comparable results. Nonetheless, robotic colectomy was linked to extended surgical duration and increased costs, leading to the conclusion that its advantages did not justify the elevated expenditure. The robotic group demonstrated a substantially lower conversion rate, reduced duration of hospital stay, and diminished blood loss, as demonstrated by a recent meta-analysis by Tschann et al[19]. However, the long-term oncological outcomes were similar between the two groups. In their propensity score–matched prospective nonrandomized study, Ferri et al[20] conducted a cost-effectiveness analysis and identified no significant difference in total costs between the robotic and laparoscopic groups. In order to determine the advantages of robot-assisted colon surgery, it is imperative to conduct additional investigations and randomized trials that focus on specific primary endpoints, such as intracorporeal anastomosis, CME with CVL, and cost-effectiveness.

CONCLUSION

The ongoing refinement of colorectal cancer treatment by the surgical community underscores the importance of CME as a symbol of advancement. Its demonstrated efficacy coupled with its capacity to standardize and enhance outcomes worldwide makes it an essential component of contemporary oncological surgery. Yadav’s work[1] serves as a reminder of the need to adopt evidence-based practices and standardize surgical strategies globally. CME is not simply a surgical procedure; rather, it embodies the pinnacle of contemporary oncological standards. The current challenge involves establishing it as a universal practice, integrating it into surgical education, and making it available to all patients irrespective of location. Overall, the future of colon cancer surgery remains promising.