Treatment and prognosis after late relapse in childhood acute lymphoblastic leukemia

: We evaluated the clinical courses and laboratory features in 13 late-relapse cases of 55 children with acute lymphoblastic leukemia who had been in complete remission for longer than their years. In 8 of 13 cases, leukemia relapsed in bone marrow; 2 with testicular, 1 with central nervous system and one with ovarian involvement. Further, extramedullary relapse not involving bone marrow occurred in 5 cases (4 testicular and 1 CNS). Late-relapse was more frequently observed in boys (37.5%) than in girls (4.4%). Initial age and leukocyte counts were of no value in predicting late-relapse. The relapse rate in cases initially treated by the VPL regimen was twice that of those by a multi-drug regimen. A second prolonged remission was achieved in 5 of 10 cases by combinations of intensive chemotherapy (modified HEX) and irradiation to the testes or CNS. On the contrary, all late relapse patients initially treated by the multi-drug chemotherapy had a poor outcome. More intensive chemotherapy, including high-dose chemoradiotherapy and bone marrow transplantation, should be employed in this group of patients.