Complete Mesocolic Excision for Right-Sided Colon Cancer - The Role of Central Lymph Nodes

Background: Complete mesocolic excision (CME) and central vascular ligation (CVL) for right-sided colon cancer may be superior to standard hemicolectomy in terms of oncological results. This hypothesis is currently being investigated in a large multicentre trial conducted by the authors of this paper (Resektatstudie). Because CVL in right-sided hemicolectomy is technically rather demanding the incidence of central node involvement is of special interest. Therefore, during the single centre pilot phase of our multicentre trial we have analysed the incidence of central lymph node metastasis in CME specimens. Patients: In 51 patients with right-sided colon adenocarcinoma (cT1-3, cM0) an open CME with CVL was performed. In the fresh specimen the central four centimetres of the ileocolic vessels that would have been presumably left in place during a standard hemicolectomy were marked with a suture. The lymph nodes in this segment were separately analysed. Results: In the CME specimen the mean lymph node count was 52.6 (range: 27-171). 35.0% (range: 13.1-65.6%) of the nodes were located in the central 4 cm segment. The proportion of patients with positive nodes was 25.5% (13/51). Of all nodes 1.97% (53/2686) were metastatic. In 3/51 (5.8%) patients the central nodeswere involved. In one patient the central nodes were the only metastatic site. UICC stage was influenced in two of the three patients who had central involvement (stage migration: UICC IIB to IIIB, UICC IIIB to IIIC). Conclusion: CME with CVL in right-sided colon adenocarcinoma increases the probability of complete removal of the local lymph node drainage and thus local metastatic lymph nodes. Considering this result an improvement of long-term survival by the CME procedure seems conceivable but needs to be confirmed by the current multicentre trial.