Acute lymphoblastic leukemia in children: nonrandomized comparison of conventional vs. intensive chemotherapy at the National Cancer Institute of Colombia.

BACKGROUND

This study aimed to compare the therapeutic efficacy of two treatments for childhood acute lymphoblastic leukemia (ALL), and to evaluate the feasibility of intensive chemotherapy in a developing country.

METHODS

The study was conducted at the National Cancer Institute in Bogota, Colombia. Untreated ALL patients under 16 years of age were divided into two groups: a historical control cohort (HC) of 141 patients treated with conventional chemotherapy and an intensive chemotherapy cohort (IC) of 130 patients treated with a modified Berlin-Frankfurt-Münster protocol (m-BFM). Patients were clinically classified into risk categories for relapse, and followed through July 31, 1995. Disease-free survival (DFS) curves were obtained using the Kaplan-Meier method and were compared by the log rank test.

RESULTS

Therapy groups had similar clinical baseline characteristics. Nonresponse rate to induction was higher in the HC group (16.3%) than in the IC cohort (7.6%) (P = 0.047), but deaths during induction were more frequent among m-BFM patients (13.8%) than in the HC group (6.4%) (P = 0.064). Bone marrow relapses after complete remission were less common in the IC group than in the HC group (19.4% and 45.9%, respectively; P = 0.0001), but central nervous system relapses showed no difference (12.8% in the HC and 16.3% under IC; P = 0.6). The DFS rates at 10 years were higher for the IC group, regardless of the baseline risk.

CONCLUSIONS

IC reduces the frequency of relapses in ALL children in developing countries, when compared to previous therapy. A highly effective therapy such as m-BFM seems to be the most important predictor of outcome in children.