Sentinel lymph node biopsy in Japan

Similar to the practice in Western countries, intraoperative lymphatic mapping and selected lymphadenectomy (SLNB) have been validated and are widely performed for the staging of melanoma in Japan. Recent studies have shown that approximately 90% (73/81) of university hospitals and several cancer hospitals routinely perform SLNB, and half of all melanoma patients receive this examination. SLNB is performed according to a variation of the standard procedure described by Morton and Cochran. The most frequently used tracers are Tc99m-tin colloid or Tc99m-phytate for scintigraphy and patent blue violet or indigo carmine as a blue dye. Some institutions use indocyanine green, which is fluorescent and can be used to visualize sentinel lymph node(s) (SLNs) under an infrared camera. The recent detection rate of SLNs has increased to more than 95% with the method using blue dye, lymphoscintigraphy, and a handheld gamma probe. In a multicenter study, the rates of metastasis in SLN were as follows: pTis, 0% (0/36); pT1, 10.7% (6/56); pT2, 21.0% (13/63); pT3, 34.0% (35/103); and pT4, 62.4% (63/101). The metastasis rate was also significantly related to ulceration of the primary tumor. Here, we discuss data from Japanese patients and the present status of SLNB in Japan.