Comparing complete mesocolic excision versus conventional colectomy for colon cancer: A systematic review and meta-analysis

Conventional colectomy, and the Japanese Society for Cancer of the Colon and Rectum (JSCCR) D2 Lymphadenectomy (LND2), are currently considered standard of care for surgical management of colon cancer. Colectomy with complete mesocolic excision (CME) and JSCCR D3 Lymphadenectomy (LND3) are more radical alternative approaches and provide a greater degree of lymph nodal clearance. However, controversy exists over the long-term benefits of CME/LND3 over non-CME colectomies (NCME)/LND2. In this study, we performed a systematic review and meta-analysis to compare the surgical, pathological, and oncological outcomes of CME/LND3 with NCME/LND2. Embase, Medline and CENTRAL databases were searched from inception until May 15, 2020, in accordance with PRISMA guidelines. Studies were included if they compared curative intent CME/LND3 with NCME/LND2. Weighted mean differences (WMD) and odds ratios (OR) were estimated for continuous and dichotomous outcomes respectively. Out of 1310 unique citations, 106 underwent full-text review, and 30 were included for analysis. In total, 21,695 patients underwent resection for colon cancer. 11,625 received CME/LND3, and 10,070 underwent NCME/LND2. No significant differences were found in post-operative morbidity and mortality. Both overall and disease-free survival favored CME/LND3 (5-year OS: OR = 1.29; 95% CI 1.02 to 1.64, p = 0.03; 5-year DFS: OR = 1.61; 95% CI 1.14 to 2.28; p = 0.007). This is the first systematic review and meta-analysis to demonstrate that CME/LND3 has superior long-term survival outcomes compared to NCME/LND2.