Prognosis of women with stage IV breast cancer depends on detection of circulating tumor cells rather than disseminated tumor cells

Background: At metastatic relapse, detection of circulating tumor cells (CTC) in peripheral blood is predictive of poor survival of breast cancer patients. Detection of disseminated tumor cells (DTC) in bone marrow (BM) is an independent prognostic factor in early breast cancer. We evaluated the prognostic value of DTC detection in the BM of metastatic breast cancer patients. Materials and methods: BM aspirates from 138 patients were screened for DTC with the pancytokeratin mAb A45-B/B3, according to the ISHAGE classification. One hundred and ten patients (80%) were enrolled before first-line treatment. Thirty-seven patients were simultaneously screened for CTC in the blood. Results: DTC detection rate in the BM was 59%. DTC were associated with bone metastasis (P = 0.0001), but not with a poorer overall survival. Adverse significant prognostic factors were hormone receptor negativity (P = 0.0004) and more than one line of chemotherapy (P = 0.002). CTC detection in the subgroup of 37 metastatic patients was associated with shorter survival (P = 0.01). Conclusions: Detection of CTC but not BM DTC had a prognostic significance in stage IV breast cancer patients. CTC in blood are a more reliable and a less invasive tool to evaluate prognostic and monitor tumor response in this metastatic setting.