Influence of late treatment on how chronic myeloid leukemia responds to imatinib

ABSTRACT: INTRODUCTION: In Brazil, patients with chronic myeloid leukemia (CML) in the chronic phase were not given first-line imatinib treatment until 2008. Therefore, there was a long period of time between diagnosis and the initiation of imatinib therapy for many patients. This study aims to compare the major molecular remission (MMR) rates of early versus late imatinib therapy in chronic phase CML patients. METHODS: Between May 2002 and November 2007, 44 patients with chronic phase CML were treated with second-line imatinib therapy at the Hematology Unit of the Ophir Loyola Hospital (Belém, Pará, Brazil). BCR-ABL transcript levels were measured at approximately six-month intervals using quantitative polymerase chain reaction. RESULTS: The early treatment group presented a 60% probability of achieving MMR, while the probability for those patients who received late treatment was 40%. The probability of either not achieving MMR within one year of the initiation of imatinib therapy or losing MMR was higher in patients who received late treatment (79%), compared with patients who received early treatment (21%, odds ratio=5.75, P=0.012). The probability of maintaining MMR at 30 months of treatment was 80% in the early treatment group and 44% in the late treatment group (P=0.0005). CONCLUSIONS: For CML patients in the chronic phase who were treated with second-line imatinib therapy, the probability of achieving and maintaining MMR was higher in patients who received early treatment compared with those patients for whom the time interval between diagnosis and initiation of imatinib therapy was longer than one year.

Frequency of acute myeloid leukemia in children attended in Belém, Pará from August 2005 to May 2009

Introdução: A leucemia mieloide aguda (LMA) tem incidência variável nas diferentes regiões do Brasil. Objetivos: Determinar a frequência dos subtipos de LMA em crianças entre 0-17 anos, atendidas em Belém, Pará, no período de agosto de 2005 a maio de 2009. Casuística e métodos: Estudo retrospectivo com 278 pacientes com diagnóstico de leucemias agudas ou crônicas com base nos critérios clínicos, morfológicos (classificação franco-americana-britânica [FAB]/Organização Mundial da Saúde [OMS]) e de perfil imunofenotípico por citometria de fluxo para determinação da frequência de subtipos de LMA. Resultados: Foram encontrados 70 (25,18%) casos de LMA; destes, 37 (52,9%) eram crianças entre 0-17 anos (idade mediana de 7 anos e 8 meses). Não houve diferença estatística em relação ao gênero. Observou-se maior frequência de LMA dos subtipos M2 (18/37 - 48,6%) e M0/M1 (10/37 - 27%), principalmente na primeira década de vida (16/28 [57,1%] LMA M2 e 9/28 [32,1%] LMA M0/M1). Conclusão: Na população pediátrica, os tipos de LMA M2, M0/M1 e M3 foram, respectivamente, as mais frequentes.