Lack of prognostic value of the periodic acid-Schiff reaction and blast cell size in childhood acute lymphocytic leukemia.

Conflicting evidence has been published as to the prognostic significance of the periodic acid-Schiff (PAS) reaction and cell size in acute lymphocytic leukemia (ALL). Therefore, a large collaborative study was undertaken to evaluate the prognostic significance of the PAS reaction and cell size of bone marrow lymphoblasts obtained at the time of diagnosis in children with ALL. Known prognostic factors (age and white blood cell [WBC] counts) were also evaluated. Data from 80 newly diagnosed cases of ALL were analyzed. These patients were treated with similar therapy by members of the Pediatric Division of the Southwest Oncology Group. The PAS reaction was scored. Microlymphoblasts were defined as having a diameter of less than or equal to 12 micron; macrolymphoblasts, greater than 12 micron. Patients 10 years and older at the time of diagnosis had a significantly shorter duration of first remission and survival than those younger than 10 years. Those with pretreatment peripheral WBCs of less than or equal to 25,000/microliter had significantly longer duration of first remission and survival than those with a peripheral WBC greater than 25,000/microliter. There was no significant difference in duration of first remission or survival in patients having predominantly macrolymphoblastic or microlymphoblastic marrows. PAS reaction was of no value in predicting the duration of first remission or survival.