Scope and value of bone marrow biopsies in metastatic cancer.

The results of examination of 1,810 bone marrow biopsies of 1,725 patients with known or suspected carcinomas are presented. The frequency of positive biopsies was 72% for unknown primaries, 42% for mammary, 32% for prostatic, 14% for pulmonary and 19% for other cancers; the overall rate of detection of metastases was 35%. The mode of spread, the grade of tumour cell differentiation and the host response to the presence of the metastases were investigated by light and electron microscopic studies and by means of antibody reactions on fresh-frozen sections. The results are presented and their relevance to the fundamental understanding of the metastatic process is outlined. Implications for clinical oncology and patient management are discussed.