Immunohistochemical detection of lymph node metastases in node-negative breast cancer patients.

Background: Axillary lymph node metastases in breast cancer patients are one of the most important prognostic factors. Many previous studies have shown that in the detection of occult micrometastases immunohistochemical methods are superior when compared to routine hematoxylin-eosin staining. The aim of the study was to document the rate of missed occult micrometastases on routine hematoxylin-eosin staining in our department, in a retrospective study.

Patients And Methods: One hundred and one tumors of patients with breast cancer were included in this study. Immunohistochemical staining was performed using Pan-Cytokeratin AE1/AE3 antibody. The number of nodes examined was 1301 (mean per patient: 12.9; range: one to 26).

Results: Of the 101 tumors studied, eleven had occult lymph node metastases detected by immunohistochemical methods. After repeated review by two independent pathologists, in two out of eleven patients lymph node metastases were confirmed even on hematoxylin-eosin staining. In nine out of eleven patients hematoxylin-eosin staining was not sufficient to detect occult micrometastases.

Conclusion: Immunohistochemical methods enhance the detection rate of occult micrometastases in axillary lymph nodes of breast cancer patients and are recommended for routine diagnostic use in patients who have been diagnosed node-negative on routine hematoxylin-eosin staining.