[Therapeutic application of sequential bone marrow biopsy in myeloma: analysis of 13 medullary biopsies]

The therapeutic applications of sequential bone marrow biopsy were investigated in 6 patients with myeloma. Our results showed that the response to chemotherapy is modified by data from quantitative bone marrow cytology which separate subgroups of patients (plasmocytes or plasmoblasts) with different prognosis. The selective disappearance of certain bone marrow components (plasmoblasts and/or diffuse infiltration) after chemotherapy results in tumoral growth retardation which is reflected in a higher objective response rate. These preliminary results emphasize the need for pretreatment bone marrow biopsy in order to select the most appropriate drugs. A prospective study involving a large number of patients is in progress; its purpose is to find out whether adding to the already known clinical classifications a classification based on the type of bone marrow infiltration and on the degree of cell differentiation is therapeutically useful.