Expert consensus on the surgical treatment of right-sided colon cancer (2024 edition, English version)

Introduction Colorectal cancer is the second most common malignancy and has the fourth highest mortality rate in China,[1] with the disease burden increasing annually.[2] Clinical research regarding right-sided colon cancer has continuously generated evidence supporting the standardization of right-sided colon cancer surgery, especially after high-quality studies, such as the clinical trial of the extent of lymphadenecto my for right-sided colon cancer. Several surgical principles have been incorporated into national and international colorectal cancer diagnosis and treatment guidelines.[3,4] These consensus statements and guidelines, however, offer only general technical instructions for patients with colorectal cancer, rather than being especially designed to address patients with right-sided colon cancer. A consensus of 55 specialists from 18 countries was initiated on complete mesocolic excision (CME) in 2022 by the CME Project Working Group. The majority of the topics covered by this consensus were anatomical strategies of CME and clinical issues with training programs and performance assessments. The consensus did not, however, include guidelines regarding surgical strategies related to right hemicolectomy, including guidelines regarding the decision between open and laparoscopic surgery or the range of lymph node dissection. Furthermore, the consensus is limited by the absence of systematic search results and descriptions of available evidence. The “Chinese expert consensus on the surgical treatment of right-sided colon cancer (2024 edition)” focuses on patients with right-sided colon cancer who require surgical treatment. By summarizing the evidence of key clinical issues, such as anatomy and surgical techniques in right hemicolectomy, and combining the practical experience of experts in the field of colorectal surgery, a Chinese expert consensus was formulated. This consensus provides evidence-based and operable consensus recommendations for general surgeons, especially colorectal specialists. This consensus has been registered in both Chinese and English on the Practice guideline REgistration for transPAREncy platform (PREPARE) with the registration number PREPARE-2024CN840. In March 2024, a consensus working group was established, and no members of the working group publicly declared conflicts of interest with the formulation of this consensus. During the clinical question selection phase, the core team responsible for establishing the consensus first formed a list of questions (19 clinical questions) after considering the important clinical questions that needed to be answered within the domain and through internal discussions. Twenty-six surgeons who were likely users of the consensus were subsequently invited. After declaring conflicts of interest, they voted based on their clinical needs to select 80% of the questions to enter the consensus question list, ultimately forming 15 clinical questions that this consensus intends to address. The method for conducting searches was then developed and reviewed by methodological experts before the systematic search was conducted. During the systematic search process, two of the questions were combined, resulting in 14 clinical questions that this consensus aims to address (for full details, please refer to the Supplementary Material, https://links.lww.com/CM9/C729). This consensus adopts the Oxford Centre for Evidence-Based Medicine: Levels of Evidence (March 2009) for grading recommendations. The strength of the recommendations is graded from strong to weak (A, B, C, and D) based on the level of evidence and considering factors such as the degree of alignment between the consensus subjects and the study population, the degree of clinical benefit, and whether there are other better treatment options. After the results of the systematic searches of the question list, the preferences of patients in China, and the pros and cons of intervention measures were synthesized, the consensus working group proposed recommendations. Statements 1 and 2 were reported according to the good practice statement, and the level of evidence and grade of recommendation were not given. Fourteen statements were sent anonymously to the expert group using an electronic survey platform on July 12, 2024. Before the next round, the experts were notified of the consensus reached through “controlled feedback” in the preceding round. To maintain the anonymity of the process, the experts were not aware of individual’s responses, only those of the whole group. This process was repeated a maximum of twice until a consensus was reached. A predefined agreement rate of 75% was set as the standard for reaching a consensus, and recommendations for all clinical questions were reached a consensus. Institutional Review Board approval was not needed, as this was an expert consensus. Anatomy Related to Surgery for Right-Sided Colon Cancer Definition and clinical significance of mesentery, fascia, and spaces in right hemicolectomy Recommendation 1: In right hemicolectomy for colon cancer, en bloc resection of the right-sided colon and the anterior aspect of the mesocolon is recommended, with the posterior aspect incorporating the Toldt’s fascia and the fusion fascia of Fredet and the vascular and lymphatic tissues between the anterior and posterior aspects of the mesocolon. Vascular anatomy in radical right hemicolectomy Recommendation 2: The appearance of the ileocolic vessels and the middle colic vessels is relatively constant, whereas variations in the right colic vessels and branches of Henle’s trunk are significant. Special attention to the anatomy of Henle’s trunk is needed during right hemicolectomy to reduce intraoperative bleeding. Medial Boundary in Right Hemicolectomy Medial boundary in standard D2 surgery Recommendation 3: In right hemicolectomy, the right side of the superior mesenteric vein may be considered the medial boundary for standard D2 lymph node dissection (Recommendation strength B, evidence level 4). Medial boundary in CME Recommendation 4: In surgeries for right-sided colon cancer, the left side of the superior mesenteric artery may be considered the medial boundary for CME, but opening the sheath of the superior mesenteric artery is not recommended (Recommendation strength C, evidence level 4). Choice of the Surgical Approach Initially resectable right-sided colon cancer Recommendation 5: Laparoscopic surgery is the preferred surgical approach for initially resectable right-sided colon cancer (Recommendation strength A, evidence level 1b). T4 right-sided colon cancer Recommendation 6: Laparoscopic surgery can be considered the preferred method for treating T4 right-sided colon cancer, with the decision to convert to open surgery depending on intraoperative conditions (Recommendation strength B, evidence level 2a). Definition of conversion to open surgery Recommendation 7: Any incision size exceeding what is needed for specimen removal or any intracorporeal operation initially planned to be completed laparoscopically that is performed through a specimen extraction site is defined as conversion to open surgery (Recommendation strength C, evidence level 4). Basic Principles of Surgery Lymph node dissection Central lymph node dissection Recommendation 8: Routine standard D2 surgery is recommended for right-sided colon cancer. However, CME could be considered for patients with suspected regional lymph node metastasis based on preoperative imaging assessment and intraoperative exploration (Recommendation strength A, evidence level 1b). Infrapyloric lymph node dissection Recommendation 9: The rate of infrapyloric lymph node metastasis in right-sided colon cancer is relatively low, and routine dissection is not recommended. However, for tumors located in the transverse colon and hepatic flexure, especially in patients with suspected infrapyloric lymph node metastasis, dissection of these lymph nodes is advised (Recommendation strength B, evidence level 2a). Ligation of the middle colic artery Recommendation 10: In right hemicolectomy, for cecal and ascending colon cancer, it is necessary to ligate only the right branch of the middle colic artery. However, for hepatic flexure colon cancer and transverse colon cancer, ligation of the trunk of the middle colic artery is needed (Recommendation strength C, evidence level 4). Extent of bowel resection Recommendation 11: For tumors proximal to the hepatic flexure, the colon should be transected at least 10 cm from the tumor in the midtransverse colon; for tumors distal to the hepatic flexure, the colon should be transected 10 cm distal to the tumor (Recommendation strength B, evidence level 4). Gastrointestinal reconstruction Anastomosis site Recommendation 12: In laparoscopic right hemicolectomy for colon cancer, the choice between intracorporeal anastomosis and extracorporeal anastomosis can be determined by factors such as vascular anatomy, tumor location, and surgeon proficiency with different techniques (Recommendation strength B, evidence level 1c). Anastomosis techniques Recommendation 13: In right hemicolectomy for colon cancer, stapled anastomosis is recommended due to its lower rate of anastomotic leak and shorter anastomosis time (Recommendation strength A, evidence level 1a). Reconstruction methods Recommendation 14: Current evidence suggests that side-to-side and end-to-side anastomosis in right hemicolectomy for colon cancer do not affect short-term outcomes, and surgeons may decide which anastomosis method to use based on specific circumstances (Recommendation strength B, evidence level 1c). Acknowledgment We would like to express our deepest gratitude to all the members of the consensus working group for their invaluable contributions to the “Chinese expert consensus on the surgical treatment of right-sided colon cancer (2024 edition)”. Funding This study is supported by the Innovation Fund for Medical Sciences (No. 2022-I2M-C&T-A-001). Conflicts of interest None. Chief experts Yi Xiao, Peking Union Medical College Hospital; Zang Lu, Ruijin Hospital; Zhongtao Zhang, Beijing Friendship Hospital; Pan Chi, Fujian Medical University Union Hospital. Previous reports The Chinese version of the consensus has been published in the Chinese Journal of Gastrointestinal Surgery. Sep 25 2024;27(9):879–890. doi: 10.3760/cma.j.cn441530-20240817-00287. Registration number PREPARE-2024CN840 on the Practice guideline REgistration for transPAREncy platform (PREPARE).