Epithelial cells in bone marrow of breast cancer patients at time of primary surgery: clinical outcome during long-term follow-up.

PURPOSE: To evaluate the detection of epithelial cells in bone marrow of breast cancer patients as an indicator of metastatic disease. PATIENTS AND METHODS: Between 1989 and 1994, bone marrow biopsies were performed on 393 breast cancer patients during primary surgery. Specimens were stained immunocytochemically for epithelial cells expressing cytokeratins or the epithelial membrane antigen. The long-term outcomes of these patients were analyzed in this study. RESULTS: In 166 of 393 patients, epithelial cells were found in bone marrow (BM) aspirates. These patients were designated BM+. The rate of tumor recurrence or cancer-related death was significantly higher in BM+ patients than in BM- patients. Multivariate analysis using the Cox regression model revealed BM status as a prognostic parameter independent of tumor size and axillary lymph node status. However, tumor size and axillary lymph node status were clearly superior prognostic parameters. CONCLUSION: Disseminated epithelial cells in BM are associated with poor clinical outcome in breast cancer patients. However, the presence of these cells is not a sufficient parameter to predict growing metastases in the majority of patients, suggesting that epithelial cells in the BM of breast cancer patients at the time of surgery have limited metastatic potential. The role of these cells needs to be further evaluated.