The effect of initial management of hyperleukocytosis on early complications and outcome of children with acute lymphoblastic leukemia
Data were collected from 124 patients with newly diagnosed acute lymphoblastic leukemia (ALL) and WBC greater than 200,000/microL seen at institutions affiliated with the Children's Cancer Study Group (CCSG) from April 1981 to May 1983. The presenting characteristics, initial management, early complications, and outcome were reviewed. All the children received vigorous intravenous (IV) hydration, alkalinization of the urine, and allopurinol. Thirty-two patients were started on full therapy with no additional measure. One or more special measures believed to reduce the complications of leukostasis and blast cell lysis were administered to 92 patients as follows: small initial doses of prednisone, 63; emergency cranial irradiation, 26; exchange transfusion, 21; and leukopheresis, 19. The incidence of CNS hemorrhage was only 3% (4/124). Seven patients expired during induction and four failed to achieve a remission by day 28. Nineteen patients (15%) had documented bacterial or fungal sepsis. Mild to moderate electrolyte abnormalities occurred in 29 patients: three patients required renal dialysis. Pretreatment with small doses of prednisone did not decrease the incidence of electrolyte abnormalities in those patients when compared with patients who received full chemotherapy. The event-free survival (EFS) for the 106 patients treated on one of the three intensive pilot studies is 55% at 36 months. On multivariate analysis the two significant adverse prognostic factors were massive splenomegaly (P = .02) and WBC count greater than 600,000/microL (P = .05). In conclusion, in patients with hyperleukocytosis the complications of blast cell lysis and leukostasis were manageable with acceptable morbidity and minimal mortality in a group of patients treated with vigorous hydration, allopurinol, and alkalinization of the urine before beginning chemotherapy. Selected patients with severe hyperuricemia and renal dysfunction may benefit from leukopheresis. No beneficial role was demonstrated for the use of small initial doses of prednisone or emergency cranial irradiation.