Lymphoblast cell size and prognosis in acute lymphoblastic leukemia in childhood.

The significance of cell size as a prognostic indicator in acute lymphoblastic leukemia (ALL) is controversial. Accuracy in measurement of cell size can be improved by determination of cell areas instead of single cell diameters. In the present study cell areas of 200 cells were determined in pretreatment bone marrows of 35 children with ALL. For better comparison with other studies which had used cell diameters only, the measured area was expressed as circle area from which the circle diameter was calculated. Cells with a diameter of greater than 12 micron were defined as macrolymphoblasts (MLB). Several clinical characteristics considered to be risk factors in ALL were ascertained for each patient. The duration of first complete remission was used to assess the prognostic significance of cell size and of number of risk factors. In contrast to previous reports patients with more than 25% MLB had longer remissions. However, nearly all patients of this group had no or one risk factor only. When patients with more than one risk factor were excluded from statistical analysis, the group with more than 25% MLB had no longer a better prognosis compared to the group with 25% MLB or less. Thus, in this study the percentage of MLB was not an independent prognostic indicator for risk of relapse in ALL.