The comparative values of bone marrow aspirate and trephine for obtaining bone scan-targeted metastases from hormone-refractory prostate cancer

Samples of metastatic prostate cancer to bone are difficult to obtain. The aim of this study was to compare the results of bone marrow aspirate and trephine biopsy for obtaining metastatic hormone-refractory prostate cancer (HRPC) samples using previous diagnostic planar 99^mTc-HDP bone scans to guide the procedure. All samples taken were for the purposes of research and molecular studies on HRPC. Twenty patients with HRPC had bone marrow aspirate and trephines taken from lesions in the posterior superior iliac spine or sacro-iliac region when shown on diagnostic 99^mTc-HDP bone scans. Three patients also underwent plain X-ray, 18F-positron emission tomography bone scan, pelvic MRI scan and 99^mTc nanocolloid bone marrow scans. These images were used to assess if the extra imaging information provided, such as three-dimensional localisation of the bone metastases, was of value for target bone metastases. Cancer cells were obtained in 15/20 (75%) cases in which a trephine biopsy was attempted and 0/20 of cases in which a bone marrow aspiration was attempted. The additional information provided by the range of other imaging investigations was of little benefit in obtaining tumour samples, but did suggest why negative biopsies were obtained in some cases after targeting with planar bone scans. We recommend the use of bone marrow trephine biopsy alone, guided by previous diagnostic 99^mTc planar bone scan as a practical method to obtain prostate cancer cells from bone metastases.