Prognostic factor analysis of central nervous system relapse in adult acute lymphoblastic leukemia. A Southeastern...

A randomized clinical trial in adult ALL has previously shown a benefit for central nervous system prophylaxis (intrathecal methotrexate plus cranial irradiation) with respect to CNS relapse-free interval, and the long-term follow-up revealed that about 20% of the patients in this multicenter trial were long survivors, probably cured. Questions that were not addressed in the earlier reports concern the time to CNS relapse as the initial site of relapse and the prognostic factors associated with initial CNS relapse. Further analysis of the 62 evaluable randomized patients has shown that in every case with CNS relapse, time to any relapse and time to CNS relapse as the first event were the same. Multivariate analysis showed that, although CNS prophylaxis is a significant favorable prognostic factor with respect to CNS relapse over time, race (nonwhite is unfavorable) and splenomegaly (unfavorable) are more significant, albeit not well explained. Future trials should examine race and splenomegaly as well as other clinical and biologic features as potential prognostic factors for CNS relapse in adult ALL.