Detection of tumor cells in the bone marrow of stage IV breast cancer patients receiving high-dose chemotherapy: the role of induction chemotherapy.

ABSTRACT

High-dose chemotherapy and hematopoietic support can produce long-term, disease-free remissions in selected patients with metastatic breast cancer. Occult bone marrow involvement may contribute to late relapse. We used five anti-breast cancer monoclonal antibodies and flow cytometry with cytological analysis of sorted immunostained cells to detect tumor cells in the bone marrow in two cohorts of patients. The first (Upfront) cohort was treated with a single course of high-dose chemotherapy and autologous bone marrow support (ABMS) without induction chemotherapy. The second (AFM) cohort received induction chemotherapy with doxorubicin, 5-fluorouracil and methotrexate prior to high-dose chemotherapy and ABMS. Of the 15 Upfront patients, seven (47%) had immunostained cells in the harvested bone marrow by flow cytometry and 8/15 (53%) had positive cytologies. Of the 49 AFM patients studied, nine (18%) had immunostained cells in the bone marrow, and only 1/49 (2%) had positive cytologies. Induction chemotherapy significantly decreased bone marrow contamination as detected by flow cytometry and cytology in patients with breast cancer. The detection of immunostained cells in the bone marrow did not predict for relapse or overall survival.