Bone marrow micrometastases in patients with stage I-II localised prostate cancer

Prostate cancer commonly metastasises to the bones. Detection of bone marrow micrometastases (BMM) may give important information that helps define treatment strategies. This study was undertaken to analyse BMM in early prostate cancer patients and to determine the accuracy of immunohistochemical (IHC) and morphological methods in detecting cancerous cells. Preoperative core bone marrow biopsy (BMB) was performed in 103 patients with T1-2, N0, M0 prostate cancer after neoadjuvant androgen blockade. BMB were examined by IHC using monoclonal antibodies for cytokeratins (CK) (18, 19, PAN) and by cytomorphology of IHC-positive cells. In 103 patients, BMM were detected in 2 cases (2%) and an additional 3 cases (3%) were classified as suspicious. IHC alone revealed positive cells in 19 patients (18%). Cytomorphology disclosed IHC false-positive staining of some apparently normal bone marrow elements such as plasmocytes. The study shows a rather low rate of BMM in early prostate cancer. It also stresses the importance of cytomorphology as an adjunct to IHC as IHC alone may not be sufficient and appropriate for BMM detection.