Bone marrow micrometastasis in breast cancer: review of detection methods, prognostic impact and biological issues.

Abstract

Immunocytochemical detection of disseminated tumour cells in the bone marrow of primary breast cancer patients at surgery has been shown to be an independent prognostic factor in single institutional studies and in a large pooled analysis. However, to date, bone marrow sampling and assessment of disseminated tumour cells is not a routine procedure in the clinical management of breast cancer patients, but will certainly play a role in a near future for risk stratification and monitoring of therapeutic efficacy. Accurate identification of disseminated tumour cells in bone marrow must be based on standardised methodologies and procedures. This review describes these methodologies and the standardised morphological criteria used for disseminated tumour cell detection. The significance of disseminated tumour cells in bone marrow and in the blood for the prognosis and prediction of response to therapy are briefly summarised. Finally, this review addresses the main biological questions raised by disseminated tumour cells in particular understanding tumour dormancy and identifying metastatic stem cells.