Recent development of sentinel lymph node biopsy for breast cancer in Japan

The number of breast cancer cases undergoing sentinel lymph node biopsy (SLNB) has been increasing with the number of articles published in Japan. SLNB using the dye method alone is performed in about one-third of patients. Analysis of questionnaire responses from 40 institutions in Japan revealed an identification rate by the dye method alone of 87%, compared with 96% using the combined method; the combined method is now recognized in Japan as superior to the dye method alone. No dyes have been specifically approved by the government for use in SLNB, and physicians have been using several inappropriate dyes as tracers for SLNB, such as indocyanine green, patent blue, indigo carmine, and isosulfan blue. The colloidal radiotracers used in Japan include tin colloid, stannous phytate, rhenium sulfate and human serum albumin. Albumin colloid and sulfur colloid are not commercially available in Japan. Small-size tin colloids, stannous phytate and rhenium sulfate all yield good results in terms of detection and false-negative rates. Provided that the surgeon has adequate experience in SLNB, a negative sentinel node can serve as a substitute for negative results from axillary lymph node dissection. Although many institutions have introduced SLNB, few reports have focused on the results of SLNB without axillary dissection because of short follow-up times and small number of patients. The final decision as to whether SLNB is an adequate substitute for axillary dissection awaits the results of prospective randomized trials.