Radioguided sentinel lymph node biopsy in early breast cancer: experience at Chang Gung Memorial Hospital.

BACKGROUND: Sentinel lymph node (SLN) biopsy can identify regional metastases and provides an alternative to axillary dissection that avoids arm morbidity. This investigation assessed the accuracy of SLN biopsy for predicting axillary node status. METHODS: A total of 174 clinical node-negative breast cancer patients and 165 SLN biopsies were enrolled. SLN biopsy was performed in a two-day protocol with backup axillary dissection: subdermally injected technetium-99 sulfur colloid to detect and localize SLN on day one; sentinel node harvesting under gamma-counter guidance on day two. Clinicopathological factors were statistically analyzed to assess the accuracy of the SLN biopsy. RESULTS: The SLN was identified in 94.3% (165 of 175) of cases. SLN biopsy had an accuracy of 98.2%, with sensitivity of 93.7%, specificity of 100%, negative predictive value of 97.5% and positive predictive value of 100%. Three SLN negative cases had non-SLN metastasis representing a false-negative rate of 6.3% (3 of 48). Tumor size was the only factor statistically correlated with the accuracy of the SLN biopsy. The diagnostic accuracy for tumors sized 2 cm or below was 100%. Hematoxylin-eosin stain followed by immunohistochemical stain increased the diagnosis of axillary metastasis from 25.5% to 29.1%. CONCLUSION: SLN biopsy can accurately forecast axillary node status in early breast cancer, particularly in patients with tumor sizes of no more than 2 cm.