Three-hundred and ninety-nine patients with acute leukemia examined during the period 1947-1964 were divided into three sequential series and their survival, from diagnosis to death, was compared.
A statistically significant increase in duration of survival for myeloblastic leukemia from a median of 2 to 5 months occurred between series I and series III. This is the first convincing evidence that 6-mercaptopurine therapy influences survival in myeloblastic leukemia.
A steady increase in median survival of patients with lymphoblastic leukemia from 4 to 8 to 12 months was found in the three series. The results of analysis of these series are compared to other reported series. The hypothesis —that the longer survivals reported for patients treated in hematology clinics compared to that of patients selected from population areas reflects patient selection—was examined and appeared unlikely.