[Estimation of tumor cell mass in childhood acute lymphoblastic leukemia: prognostic significance and practical application].

A retrospective statistical analysis of the acute lymphoblastic leukemia study BFM 70/76 revealed the prognosis being strongly dependent on the initial leukemia cell count/mm3 in the peripheral blood, and the enlargement of liver and spleen below the costal margin. Based on postmortem examinations reported in the literature a method was developed to estimate the tumor mass in these three compartments in an order of magnitude. The estimated blast cell mass related to the patient's body weight proved to be highly significant (p much less than 0.001). Simplification of the method led to the definition of a "risk factor" allowing the separation of patients into 3 groups with a distinctly different risk for relapse. In the current study BFM 81 the risk factor is used to stratify patients with respect to the individually needed therapeutic intensity.