The clinical study of micro-metastatic cancer by bone biopsy.

Bone marrow biopsies were investigated for the presence of neoplastic cells in 3150 patients with known or suspected malignancies. Marrow involvement was found in 42 per cent (359 of 838) cases of carcinomas, 15 per cent of 772 cases of Hodgkin's disease, 55 per cent of 1125 cases of malignant lymphoma, 75 per cent of 428 cases of multiple myeloma. In 139 cases of occult primaries the incidence of marrow involvement was 82 per cent. Micrometastases were found in 18 per cent of 359 positive biopsies from patients with solid tum ours. In this group no correlation was established between haematological findings in the peripheral blood and the size of the metastases. There was a striking variability in the type and components of the marginal zone at the interface between metastases and hematopoietic tissue, most probably due to differences in characteristics of the neoplastic cells. The high percentage of marrow involvement by metastatic carcinoma indicates that bone marrow biopsy could profitably be included in the initial investigation of patients with solid tumours.