Comparison of circulating tumor cells (CTC) in peripheral blood and disseminated tumor cells in the bone marrow (DTC-BM) of breast cancer patients.

PURPOSE: The detection of disseminated tumor cells in the bone marrow (DTC-BM) of breast cancer patients is an independent prognostic factor. In recent years, the focus of research was on finding methods for the detection of circulating tumor cells (CTC) in peripheral blood (PB). In this study, we investigated the presence of DTC-BM and CTC by simultaneous examinations in 202 patients at different stages of the disease.
METHODS: Immunocytochemical examination of DTC-BM (10-20 ml of BM) with the anti-cytokeratin (CK) antibody A45B/B3 followed a standardized protocol. Analysis of PB (7.5 ml) for the presence of CTC was performed with the CellSearch Analyzer system (Veridex, Raritan, NJ, USA).
RESULTS: Overall, DTC-BM were detected in 57/202 (28.2 %, 1->1,000 DTC) and CTC in 41/202 (20.3 %, 1-411 CTC) patients. Congruence of findings was 71.3 % (144/202, p = .002). In 147 pts with primary diagnosis, congruence of results was 69.4 % (102/147). There was no significant correlation between DTC or CTC and the established pathological factors. After a median follow-up time of 34 months (0-82), presence of CTC was borderline significant for tumor-associated death (p = .060). For 41 patients at recurrence-free follow-up, congruence of results was 75.6 % (31/41, p = .018). In this group, there was a patient with both the highest DTC (>1,000) and CTC (411) count, and she presented with distant metastases 3 months later and had died 5 months after that. Of 14 patients with metastatic disease, 9 showed both DTC and CTC (overall congruence 78.6 %, p = .176).
CONCLUSION: There was significant congruence between DTC and CTC, which even increased in patients at follow-up and in those with metastases. Repeated CTC examinations could be a valuable tool for monitoring patients or the effectiveness of therapies.