A comparative study of central nervous system irradiation and intensive chemotherapy early in remission of childhood acute lymphocytic leukemia

Abstract

A study was designed to determine whether a one‐week course of intensive chemotherapy and 2400 rads craniospinal irradiation prolonged complete remission of acute lymphocytic leukemia (ALL) in children. Of 110 patients entered into the study, 104 (94%) attained complete remission, 94 of whom were available for the 2 randomizations. They were randomly assigned to receive or not receive one week of high‐dosage intravenous chemotherapy and, 4 weeks later, were again randomized to receive or not receive 2400 rads cobalt‐60 craniospinal irradiation. Patients randomized for no irradiation were to receive identical radiotherapy only if and when central nervous system (CNS) leukemia developed. The one week of intensive chemotherapy had no effect on the duration of remission or on the frequency or site of relapse, but irradiation had a marked effect. Complete remission was terminated by CNS leukemia in only 2 of 45 children who received “prophylactic” craniospinal irradiation compared to 27 of 49 not irradiated. Five of the 25 children who were given “therapeutic” irradiation for demonstrated CNS leukemia have already had recurrences despite continuous hematologic remission. Under the conditions of this study, we conclude that one week of intensive chemotherapy does not prolong remission, that 2400 rads craniospinal irradiation early in remission prevents or delays CNS leukemia and prolongs complete remission, and that once CNS leukemia develops, 2400 rads craniospinal irradiation is not sufficient to eradicate it. Copyright © 1972 American Cancer Society