[Current status of sentinel node navigation surgery in colon cancer]

The feasibility of sentinel node (SN) mapping and its diagnostic reliability are now being determined in colorectal cancer, but the reports issued in 2000 or later suggest that they are promising with SN detection rates of 94-100% and overall diagnostic accuracy of regional lymph node status based on SN status of 86-100%. In particular, patients with a pT1 or pT2 colorectal cancer are suggested to be the best candidates for SN mapping, with diagnostic accuracy of almost 100%. On the contrary, the effects on recurrence and survival rates in colorectal cancer have not yet been verified between patients with and without micrometastasis in the SN. In accordance with the Japanese Classification of Colorectal Carcinoma, surgery for D2 (or D3) lymph node dissection have been routine in Japan for T1 or T2 colon cancers without any postoperative sequelae, and can harvest nearly all SNs without lymphatic mapping, because SNs are anatomically distributed in the paracolic and intermediate nodes. Patients with a T1 or T2 colon cancer are the best candidates for sentinel node navigation surgery (SNNS) as well as for laparoscopy-assisted colectomy (LAC). However, intraoperative colonofiberoscopy to inject a pigment tracer into the colic wall for lymphatic mapping is problematic to the LAC procedure thereafter. For this reason, SNNS might not be accepted widely in colon cancer surgery in the near future.