At present, central nervous system (CNS) leukemia is one of the principal causes for termination of complete remission in acute lymphocytic leukemia (ALL). The factors which influence the increase of CNS infiltration have been studied comparing different parameters (age, initial peripheral WBC count, type of leukemia, and presence or absence of initial organomegaly) to determine the leukemia population with highest risk of developing this syndrome. A total of 127 cases of acute lymphoid leukemia (ALL) (98 children and 29 adults) and 101 acute myelocytic leukemia (AML) (41 children and 60 adults), on the same treatment protocol from 1967 to 1970, were included in this study. The median survival and the rate of incidence of symptomatic CNS leukemia was 18 mo and 32% in ALL and 4 mo and 7% in AML. The incidence of CNS leukemia per month of survival was similar in both groups: 4 mo, 3% in AML and 4% in ALL, at 8 mo, 13% in both ALL and AML. The incidence of CNS leukemia was higher in children with ALL than in adults: 41% in children and 19% in adults at 20-mo survival. Organomegaly (spleen, liver and/or lymph nodes) as an early manifestation increased the risk of CNS involvement. The CNS infiltration was significantly greater in patients with high initial peripheral WBC count. The incidence of meningeal leukemia did not differ in ALL and AML. In conclusion, CNS leukemia infiltration was more frequent in children with initial organomegaly and high WBC count at the time of diagnosis.

A total of 114 previously untreated patients with myeloblastic leukemia was included in a sequential therapy protocol. Daunorubicin, vincristine, and prednisone were employed for the first 3 weeks, followed by two or more 5‐day courses of cytosine arabinoside and 6‐mercaptopurine; there was a 5‐day rest between courses. Maintenance therapy was as follows: the continuing 6‐mercaptopurine and methotrexate treatment was interrupted every 30 days for sequential reinforcement courses consisting of one dose of daunorubicin and vincristine and 7 days of prednisone, or by a 5‐day course of cytosine arabinoside plus 6‐mercaptopurine. Of the 114 patients, 48 obtained complete remission, 14 had partial remission, 16 failed to respond, and 36 died during the course of treatment. The remission rate in children (under 16) was 57%; in adults (16–45) 54%; and in those over 45, 19%. The difference in the incidence of complete remission in patients under 45 and those over 45 was statistically significant (p < 0.01). The median duration of complete remission was 8 months: 12 months in children and 5 months in adults. The over‐all survival rate was 4 months: 13 months for patients with complete remission, 4 months for those with partial remission, and 1 month for patients who did not respond to therapy. The difference in survival of those with complete remission and all the others was significant (p < 0.01).

Between May 1985 and November 1988, 143 adult patients with previously untreated acute nonlymphocytic leukemia were randomized to receive mitoxantrone and cytarabine (MTT+Ara-C) or daunomycin and cytarabine (DNM+Ara-C) in order to compare the efficacy and acute and chronic toxicities. Therapy consisted of 3 days of MTT 12 mg/m2/i.v. or DNM 45 mg/m2/i.v.; both groups received Ara-C 100 mg/m2 daily by continuous infusion (CI) for 7 days. Those who failed to achieve a complete remission after one induction course received a second induction course for 2 and 5 days at the same doses. All the patients who achieved complete remission received two consolidations of 2 days of MTT or DNM and 5 days of Ara-C in CI at the same dose as for induction. Of the 72 patients on MTT+Ara-C, 38 (53%) achieved complete remission, compared with 29 (43%) of 67 treated with DNM+Ara-C. Three and 5 patients had partial remission, 7 and 18 failed to respond, 24 and 15 died in the first 21 days of induction, of those treated with MTT+Ara-C or DNM+Ara-C, respectively (p = 0.34). Median duration of complete remission and survival was 185 and 103 days or 165 and 160 days, respectively (p = 0.85). More early deaths were observed with MTT+Ara-C due to greater myelosuppression, and a higher incidence of failure with DNM+Ara-C. No significant differences between treatment groups were observed in 21 categories of adverse events. The results demonstrate similar incidence of complete response, length of duration of complete remission, overall survival, and toxicity with MTT+Ara-C and DNM+Ara-C.