[Key issues in sentinel node biopsy for breast cancer].

Whereas the majority of surgeons in Western countries perform sentinel node biopsy (SNB) for early breast cancer, the majority of Japanese surgeons do not. Veronesi very recently reported the results of a clinical trial in which SNB without axillary lymph node dissection for small breast cancer did not increase axillary recurrence. Thus, sentinel node surgery has been accepted as a safe and accurate method of screening the axillary nodes for metastasis in women with small breast cancer. SNB should thus be recommended as standard care for early breast cancer in Japan. SNB for patients with ductal carcinoma in situ (DCIS) may be performed according to the decision of doctors or patients in each case, because the indication of SNB for DCIS is controversial. Since preoperative chemotherapy could increase the rate of false-negative sentinel nodes because of the induced lymphatic changes, SNB is thought to be safer before than after preoperative chemotherapy. Current evidence does not allow internal mammary SNB to be recommended as a standard procedure, but as patients with internal mammary node involvement may benefit from adjuvant systemic treatment, internal mammary SNB should be further studied in this context. Preoperative diagnosis of an axillary metastasis using fine-needle aspiration cytology (FNAC) under ultrasonographical imaging or core needle biopsy under MR imaging can cost-effectively decrease the indications of SNB.