Tumor cells in circulating blood may accurately indicate prognosis and tumor response to treatment for patients with metastatic breast cancer, whereas measures of tumors circulating in bone marrow do not. These findings were recently published in the Annals of Oncology.
For breast cancer patients with relapsed or recurrent disease, the presence of circulating tumor cells in the blood is predictive of poor survival. Circulating tumor cells can also be measured in the bone marrow, a method previously used to predict outcome of patients with early-stage breast cancer. The use of bone marrow fluids, however, has not been fully studied among women with more-advanced breast cancer. As well, using bone marrow fluid requires a more-invasive bone marrow aspiration to withdraw blood and fluid for examination.
The aim of the current study was to compare the two sources of tumor cells (blood and bone marrow) and determine whether bone marrow testing could indicate prognosis in advanced breast cancer as accurately as blood testing. Researchers measured circulating tumor cells in bone marrow fluids from 138 patients, 110 of whom had not yet received breast cancer treatment. Additionally, 37 patients were simultaneously screened for circulating tumor cells within the blood.
- The rate of detection of the tumor cells within the bone marrow was 59%.
- The presence of tumor cells within the bone marrow was associated with bone metastasis but not necessarily with poorer overall survival.
- Among the 37 patients whose blood was evaluated for tumor cells, circulating tumor cells were associated with a shorter overall survival.
- Additional analyses revealed that other factors negatively affecting prognosis included negative hormone receptor status and more than one course of chemotherapy.
Comparison between blood and bone marrow testing reveals that although tumor cells can be detected within the bone marrow, they are not related to poorer survival; circulating tumor cells in the blood, however, were predictive of shorter overall survival. Researchers concluded that among metastatic breast cancer patients, identifying circulating tumor cells within the blood is a more accurate and less invasive predictor of prognosis than evaluation of tumor cells within the bone marrow.
Reference: Bidard, F., Vincent-Salomon, A., Sigal-Zafrani, B., et al. Prognosis of women with Stage IV breast cancer depends on detection of circulating tumor cells rather than disseminated tumor cells. Annals of Oncology. 2008. 19(3): 496-500.