Aim: To evaluate the efficiency of the original ALL-MB-2002 protocol within the multicenter study of treatment of acute lymphoblastic leukemia (ALL) in children.
Subjects and methods: A total of 1873 primary patients with ALL aged 1 to 18 years, of whom 1544 patients were enrolled in this study, were notified at 36 clinics of Russia and Belarus from April 15, 2002, to January 1, 2008.
Results: With the median observation of 4.12 years, 7-year event-free survival (EFS) was 73 +/- 13%; overall survival (OS) 78 +/- 2%; relapse-free survival 82 +/- 1%. The rates of EFS and OS were equal and amounted to 76 +/- 2 and 80 +/- 2% in the standard-risk group (SRG) and intermediate-risk group (ImRG), respectively. In the high-risk group (HRG) patients, EFS and OS were as high as 30 +/- 6 and 37 +/- 6%, respectively. The frequency of relapses with central nervous system lesion was as much as 4.7% in all the patients, 6-year cumulative risk for isolated neurorecurrences being 2.5% in the SRG patients. Adolescents, patients with the baseline leukocytosis (more than 100 x 10(9)/l), and those with a splenic size of over 4 cm or more from the costal arch margin had substantially worse survival rates. A poor early response to therapy (on induction days 8 and 15) was also associated with its lower efficiency.
Conclusion: Despite a considerable rise in the number of centers and a slight increase in the intensity of therapy, the results of the new ALL-MB-2002 protocol are as minimum equivalents obtained in the use of the previous ALL-MB-91 protocol. A significant improvement in the overall results of therapy and a reduction in the cumulative risk for isolated neurorecurrences were noted in the ImRG patients.