Extent of lymphadenectomy for surgical management of right-sided colon cancer: Multicenter, open label, randomized, controlled trial.

Abstract

3575 Background: Complete mesocolic excision (CME) is being increasingly used for the treatment of right-sided colon cancer although there is still no strong evidence that CME provides better long-term oncological outcomes than D2 dissection. The controversy is mainly regarding the survival benefit from extended lymph node dissection emphasized by CME. Methods: This randomized, controlled, unblinded, phase 3, superiority trial involved 17 hospitals in China. Totally 1,072 patients diagnosed with stage T2-T4aNanyM0 or TanyN+M0 right-sided colon cancer were enrolled from January 11, 2016, through December 26, 2019. Participants were randomly assigned (1:1 ratio) to undergo either CME (n=536) or D2 dissection (n=536) during laparoscopic right colectomy. The primary outcome was the 3-year disease-free survival (DFS), and the main secondary outcome was the 3-year overall survival (OS). Results: Among 1072 patients, 77 were excluded after randomization. The remaining 995 patients (median age 61years, 59% male) were included in the primary analysis (CME [n=495] vs. D2 dissection [n=500]). The 3-year primary outcome assessment was completed for 97% patients. No significant differences were found between the groups in 3-year DFS (86.1% in CME group vs. 81.9% in D2 group; HR = 0.74; 95% confidence interval [CI]: 0.54-1.02; P = 0.06) or in 3-year OS (94.7% in CME group vs. 92.6% in D2 group; HR = 0.70; 95% CI: 0.43-1.16; P = 0.17). Conclusions: For primary surgical excision of right-sided colon cancer, complete mesocolic excision did not improve disease free survival, compared to standard D2 lymph node dissection. Standard D2 dissection should be the routine procedure for these patients. CME should only be considered in patients with obvious mesocolic lymph node involvement. Trial Registration: ClinicalTrials.gov Identifier: NCT02619942. Clinical trial information: NCT02619942 .