Epithelial cells expressing cytokeratins-19 and bone marrow micrometastases in patients with breast cancer at the 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 2001 and 2005, bone marrow biopsies were taken from 79 breast cancer patients during primary surgery. Specimens were stained immunocytochemically for epithelial cells expressing cytokeratins or epithelial membrane antigen. The long-term outcomes of these patients were analyzed.

Results: In 51 CK-positive results of 79 patients, epithelial cells were found in the bone marrow (BM) biopsies. These patients were designated CK(+). The rate of tumor recurrence or cancer-related death was significantly higher in CK(+) patients than in CK-negative patients. Multivariate analysis using the Cox regression model revealed BM status as a prognostic parameter independent of axillary lymph node status.

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, 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.