Bone marrow micrometastases and adjuvant treatment of breast cancer

The immunohistochemical detection of epithelially derived cells in the bone marrow of patients with primary breast cancer has been shown to be associated with increased risk of distant relapse as well as higher rates of cancer-related death. Despite the correlation between bone marrow micrometastases and poor outcome in breast cancer patients, bone marrow status does not yet have an established role in patient management. In this prospective study, adjuvant therapy recommendations for 43 patients with stage I, II, or III breast cancer treated with lumpectomy or mastectomy, sentinel lymph node biopsy and/or axillary dissection, and intraoperative bone marrow aspiration were recorded. Recommendations were made by a multidisciplinary tumor board both blinded and unblinded to the results of the bone marrow aspiration. In our study, 10 of the 43 breast cancer patients were found to have bone marrow micrometastases. Four of these patients (40%) had axillary lymph node metastases. When blinded to the results of the bone marrow aspiration, the tumor board recommended adjuvant chemotherapy for these four node-positive patients, as well as two node-negative patients. When unblinded to the results of the bone marrow aspiration, the tumor board did not change its recommendations for any of these six patients. The remaining four node-negative, bone marrow-positive patients were not advised to have adjuvant chemotherapy by the tumor board when blinded to bone marrow status. However, once the tumor board was informed of the presence of bone marrow micrometastases, adjuvant chemotherapy was recommended for all of these patients. The results of this pilot study indicate that the presence of bone marrow micrometastases in breast cancer patients with stage I, II, or III disease does influence recommendations for adjuvant chemotherapy, particularly in patients with node-negative disease.