Background & objective: Axillary lymph node dissection (ALND) is routinely performed during surgery for breast cancer, but whether ALND could increase survival rate of early stage breast cancer patients remains controversial. Recently, replacing ALND with sentinel lymph node (SLN) biopsy has became a hotspot in breast cancer research. This study aimed to evaluate the reliability and accuracy of SLN biopsy for early stage breast cancer, and to discover the significance of multiple step section level cytokeratin immunohistochemistry in identifying micrometastatic disease.
Methods: SLN biopsy was performed on 121 patients with T1 or T2 breast cancer: methylene blue-labeling was used in 38 patients (methylene blue group), double-labeling of (99m)Tc sulfur colloid and methylene blue was used in 83 patients (combination group). Lymphoscintigraphy and hand-hold gamma detector were used to localize SLNs before operation. All SLNs and ALND lymph nodes were pathologically examined. The tumor-negative SLNs were cut at three levels, and detected by immunohistochemistry.
Results: Success rates were 81.6% in methylene blue group, and 95.2% in combination group; accurate detection rates of axillary lymph nodes were 93.5% in methylene blue group, and 97.5% in combination group. SLNs were found in 19 patients (23%) by lymphoscintigraphy, and 76 patients (92%) by hand-hold gamma detector, respectively (P=0.04). A total of 194 negative SLNs, detected by routine pathologic examination, were re-examined by multiple step section level cytokeratin immunohistochemistry; micrometastatic diseases were identified in 21 SLNs of 13 patients. The accuracy rate of combined examinations was 98.7%, and the false-negative rate was 3.2%.
Conclusions: The axillary node status can be predicted by SLN biopsy; double-staining is better than methylene blue-labeling. The role of lymphoscintigraphy in SLN biopsy needs further explore. Multiple step section level cytokeratin immunohistochemistry can improve detection rate of micrometastatic diseases.