[Medial border of D3 lymphadenectomy for right colon cancer]

The extent of D3 lymphadenectomy for right colon cancer, especially the medial border of central lymph node dissection remains controversial. D3 lymphadenectomy and complete mesocolon excision (CME) are two standard procedures for locally advanced right colon carcinoma. D3 lymphadenectomy determines the medial border according to the distribution of the lymph nodes. The mainstream medial border should be the left side of superior mesenteric vein (SMV) according to the definition of D3, but there are also some reports that regards the left side of superior mesenteric artery (SMA) as the medial border. In contrast, the CME procedure emphasizes the beginning of the colonic mesentery and the left side of SMA should be considered as the medial border. Combined with the anatomical basis, oncological efficacy and technical feasibility of D3 lymph node dissection, we think that it is safe and feasible to take the left side of SMA as the medial boundary of D3 lymph node dissection. This procedure not only takes into account the integrity of mesangial and regional lymph node dissection, but also dissects more distant lymph nodes at risk of metastasis. It has its anatomical basis and potential oncological advantages. However, at present, this technical concept is still in the exploratory stage in practice, and the related clinical evidence is not sufficient.