[Acute lymphoblastic leukemia in children with initial leucocytosis above 50,000/mm3: summary of treatment results of Polish Pediatric Leukemia/Lymphoma Study Group].

Initial leucocytosis, presence of t(9;22) and t(4;11) translocations and poor response to therapy with steroids or induction chemotherapy are still included to poor risk factors group. From 1981 to 1986, children with acute lymphoblastic leukemia (ALL) and initial WBC above 50,000/mm3, achieved significantly worse treatment results than children with lower WBC: over 6-year disease-free survival were respectively 33% and 60%. In attempt to improve treatment results in children with hyperleucocytosis, modified American protocols called: New York (1987), New York I (1997), and New York II (1999) were introduced consecutively in the centers of Polish Pediatric Leukemia/ Lymphoma Study Group. Actually treatment results obtained with those protocols in three groups of patients: group I: 214 children (1987-1996), group II: 58 children (1997-1999), and group III: 77 children (1999-2001) are presented. The observation was completed in March 31, 2004. In evaluated groups the first complete remissions (CR) were achieved in 91%, 95%, and 96% of patients, respectively. Relapses occurred in 72 patients of group I (37%), in 12 patients of group II (21%), and in 13 patients of group III (18%). The 5-year overall survivals were: 62%, 79%, and 78% (p=0.05) respectively; 5 year event-free survivals (EFS) were: 52%, 74%, and 69% (p=0.01) respectively. A significant improvement in treatment results in second compared with first group was achieved. Treatment results obtained with New York II are comparable with results obtained with New York I. The analysis of treatment results achieved shows the improvement of the prognosis in children with ALL and initial WBC above 50 000/mm3 in comparison with patients treated before 1987. There is strong necessity of unification of risk group qualification criteria in childhood ALL in term of comparable estimation treatment results achieved in different centers all over the world.