[New data about oligoblastic leukemias. Apropos of an analysis of 120 cases].

We studied 120 aptients within the following condition: moderate bone marrow myeloblastosis (blast cells + promyelocytes less than or equal to 50 p. cent); quantitative and/or qualitative medullary insufficiency; preservation of maturation of the granulocytic line without a gap; WBC count less than 20 000/mm-3. Computer analysis pointed out the following results: 1. This group may be differenciated from the group of acute myeloblastic leukemias by: a) a predilection for subjects older than 60 in 73 p. cent of cases; b) male dominance in 70 p. cent of cases; c) a sharply defined improved prognosis with a median of survival of 15 months and with more than 30 p. cent of survivors for more than two years; d) death in 63 p. cent of teh cases is directly due to a complication of bone marrow insufficiency, and only in 14 p. cent of the cases is related to blastic invasion; e) a complete absence of favourable response to intensive chemotherapy. 2. There are five initial prognostic parameters which are of statistical significance: a) the hemoglobin level; b) the sedimentation rate; c) the platelet count, the level of bone marrow cellularity, and age. 3. Multidimensional analysis makes it appear that the whole population obeys a unidimensional phenomenon and depends on a common "biological axis" constituted by the five prognostic factors which are inter-related. 4. The disease nevertheless may be subdivided into three subgroups; a) High inflammatory hypoplastic forms are a very high risk group; b) The group of slowly invasive acute leukemias in young subjects is a bad or moderately poor risk group; c) The forms with a purely qualitative disorder of myelopoiesis with very low evolutive potential. These observations point to: a) The concept of OBL as an entity of a distinctive type including the preleukemic syndrome, the myelo-monocytic leukemias, and the smoldering leukemias; b) The concept of a unique and basic bone marrow disorder which embraces the OBL and the common acute myeloblastic leukemia.