The clinical significance of tumor cells in bone marrow or apheresis product and the efficacy of CD34+ selection and high-dose chemotherapy in patients with Stage III breast cancer.

The purpose of this study is to determine the presence of disseminated tumor cells in bone marrow or apheresis product, and also to evaluate the clinical significance of contaminated products and the efficacy of CD34(+) selection and high-dose chemotherapy in patients with Stage III breast cancer. Fifty-five patients were enrolled in this prospective cohort study. Whereas CD34(+) positive selection was not carried out in the first group (unselected group, n:31), CD34(+) positive selection was performed in the second group (CD34 selected group, n:24). Tumor cells were detected with anticytokeratin monoclonal antibody in the bone marrow, apheresis product and positive fraction. Tumor cells were found in six (19.3%) patients in unselected group and four patients (16.6%) in CD34 selected group (P = 0.76). The percentages of distant metastases were found higher in unselected group (51.6% vs. 25%, P < 0.01). Although there were no differences between the two groups for disease free survival (DFS; 44% vs. 74%, P = 0.24) or overall survival (54% vs. 68%, P = 0.84), DFS was significantly lower in patients with tumor cells than in patients without tumor cells (21% vs. 62%, P = 0.02). In conclusion, the presence of tumor cells in bone marrow or apheresis product decreases DFS in patients with Stage III breast cancer who underwent high-dose chemotherapy. CD34(+) selection does not change survivals, but it may decrease the distant metastases.