Sentinel Lymph Node Biopsy Using Radioactive Material in Breast Cancer Patients

ABSTRACT

PURPOSE: In breast cancer, the single most important prognostic indicator is the axillary nodal status of the metastasis. This study was designed to discern the accuracy of sentinel node biopsy using radioactive material for the prediction of axillary nodal status. METHODS: The study group was selected from the Department of Surgery at Yonsei University Yongdong Severance hospital, and comprised 54 patients diagnosed with breast cancer with clinical stages I or II from Nov. 1998 to May. 1999. We performed lymphoscintigraphy and gamma-probe with 99mTc-antimony trisulfide colloid for the detection of sentinel nodes. The radiotracer was injected peritumorily 2 hours prior to the operation. During, surgery and after the sentinel node biopsy was performed, level I and II axillary lymph node dissection was completed. The sentinel node was divided into 3 pieces evenly. One piece was tested for frozen section diagnoses and the others were fixed for H&E staining and immunohistochemistry (IHC) using cytokeratin antibody to detect metastasis. RESULTS: The mean number of the sentinel nodes was 1.59. The detection rate of the sentinel node was 94.4% (51/54). Among 35 patients with negative sentinel nodes on frozen section, 4 patients (11.4%) demonstrated tumor metastasis on both permanent serial H&E sections and IHC using cytokeratin. Of the 31 patients with negative sentinel node by permanent serial section, 4 patients displayed metastasis in nonsentinel axillary nodes. These results revealed that thesensitivity of the sentinel node biopsy was 83.3% and the negative predictive value was 81.1%. The false negative rate of the sentinel node biopsy was 16.7% with the permanent H&E and IHC section and 33.3% with the frozen section. In particular, in cases with tumors less than 2 cm, the sensitivity was 100% in frozen section as well as permanent section. CONCLUSION: A combination of preoperative lymphoscintigraphy and gamma probe-guided methods achieves high success rates in the identification of sentinel nodes. Multiple serial sections and IHC of the nodes are required to detect the micrometastasis of the sentinel nodes. The sentinel node biopsy is significantly accurate and may be considered as an alternative to replace the routine axillary node dissection, particularly in T1 breast cancer patients.