Minimally invasive complete mesocolic excision and central vascular ligation for right colon cancer: Defining the radicality of central lymphadenectomy.

Abstract

715 Background: Complete mesocolic excision (CME) with central vascular ligation (CVL) has been advocated for right colon cancer (RC), but the radicality of lymphadenectomy remains controversial. Optimal D2 lymphadenectomy removes all intermediate nodes with high ligation (HL) of feeding vessels, while D3 lymphadenectomy additionally exposes and retrieves nodes along ventral superior mesenteric vessels (SMA/V). We aim to evaluate minimally invasive CME-CVL, explicitly defining the radicality of central lymphadenectomy. Methods: Patients who underwent minimally invasive resection for RC between 2008 and 2016 were identified from a prospective institutional database. CME was standard. The radicality of central lymphadenectomy was defined as high ligation (HL, optimal D2) vs central node dissection (CND, D3) after review of operative reports and/or videos. A blinded radiologist evaluated the pre- and post-operative CT scans for radiographically abnormal nodes. Results: Among 200 patients, 169 (84.5%) underwent laparoscopic and 31 (15.5%) robotic resection. Central lymphadenectomy was performed as HL in 58 (29%) and as CND in 142 (71%) patients. Preoperative imaging identified abnormal D2 nodes in 33.0% and D3 nodes in 2.6%. CND was performed in 73% of those with abnormal D2 and 100% of those with abnormal D3 nodes. Pathologically positive nodes were identified in 41% (37.9% of the HL and 42.3% of the CND, p=0.64). The median number of nodes retrieved was 27 and 32, respectively. No patient had residual abnormal node on post-operative imaging. The 30 day mortality rate was 0%, and morbidity rate was 15% (4% grade 3, 11% grades 1-2). After a median of 22 months, one (0.5%) patient recurred locally at the anastomosis. Conclusions: Minimally invasive CME-CVL can be safely performed with excellent nodal yield with both optimal D2 as well as D3 lymphadenectomy. With imperfect clinical nodal staging, the near-zero local recurrence rate observed supports CME with optimal D2 lymphadenectomy as a minimum standard and D3 lymphadenectomy when radiographically abnormal nodes are identified.