Immunohistochemistry with pancytokeratins improves the sensitivity of sentinel lymph node biopsy in patients with breast carcinoma

BACKGROUND. Sentinel lymph node (SLN) biopsy is being investigated as a sta ging procedure for breast carcinoma. The authors evaluated whether immunohi stochemical (IHC) analysis improves the sensitivity of this procedure. METHODS. Forty-four women dth breast carcinoma were recruited for SLN biops y. Preoperative lymphoscintigraphy tvas followed by intraoperative localiza tion using a handheld gamma probe and blue dye. After SLN identification, a n immediate complete axillary lymph node dissection was performed in all pa tients. All lymph nodes were subjected to routine histology (hematoxylin an d eosin [H&E]) and IHC using antibody to cytokeratins. RESULTS. The SLN was identified in 41 of 43 patients (95%), Successful SLN identification was independent of biopsy technique (open surgical [95%] vs. fine-needle aspiration/core needle biopsy [96%]). Twelve of 41 patients (2 9%) had evidence of lymph node metastasis in the SLN by routine histology. Of the twenty-nine patients with H&E negative SLN, 3 were found to have met astasis by MC for a conversion rate of 10%. Fifteen of 41 patients (37%) ha d evidence of metastasis in SW. All 26 patients with H&E and IHC negative S LN had negative nonsentinel lymph nodes by routine histology and MC (100% n egative predictive value). All patients with tumors < 2 cm and micrometasta sis to the SLN had no additional lymph node disease, in contrast to patient s with lesions > 2 cm or patients with macrometastasis to the SLN (P = 0.00 7). CONCLUSIONS. These results confirm that SLN biopsy is extremely accurate fo r patients with breast carcinoma, even after open surgical biopsy. IHC anal ysis or serial sectioning of SLN improves the sensitivity of this staging t echnique. Cancer 1999;85:1098-103, (C) 1999 American Cancer Society.