Detection of bone marrow micrometastases in the rib marrow of head and neck cancer patients: a prospective pilot study.

Flow cytometry has been validated as an objective method of demonstrating and quantifying micrometastases. Micrometastases within bone marrow indicate a poor prognosis in patients with upper gastrointestinal, colorectal and breast epithelial tumours. We prospectively sought to assess the feasibility of testing rib marrow for bone marrow micrometastases in head and neck cancer and to report their frequency in a cohort of patients. Nine patients were enrolled in the study. Bone marrow was obtained before manipulation of the primary tumour. Micrometastatic cells were detected by staining contaminant cytokeratin-18 positive cells and using the twin techniques of immuncytochemistry and flow cytometry. Cellular marrow was retrieved in 100% of cases. Micrometastases were detected in one out of nine epithelial tumours on both flow cytometry and immunocytochemistry. The detection rate appeared to be independent of TN staging. We were unable to culture the cells. Preoperative detection of bone marrow micrometastases may reflect transient shedding of cells, metastatic potential or residual disease. This prospective study confirms the feasibility of using rib marrow in future studies investigating micrometastases in head and neck cancer.