Effect of the intermittent prophylactic treatment of the central nervous system in adults with acute leukemia.

Nineteen patients with acute leukemia, who achieved complete remission between January, 1980 and March, 1983, were given 10 mg of methotrexate (MTX) and 20 mg of prednisolone (PSL) intrathecally at 1st, 3rd, 6th, 10th and 15th month after the termination of consolidation therapy followed by the same dose twice a year, when the intensification therapy was being performed. During the observation period of 29 to 68 months, none developed central nervous system (CNS) leukemia. On the other hand, the incidence of CNS leukemia in patients given the prophylactic intrathecal treatment once or twice just after the complete remission was 35% (7/20) compared with 24% (8/33) in patients without treatment. No statistical difference was observed in these groups. The intrathecal administration of MTX and PSL is easy to perform and no adverse reaction was observed in our series. It is concluded that the intermittent prophylaxis with MTX and PSL is of benefit in preventing CNS leukemia in adults patients with acute leukemia.