The role of craniospinal irradiation (csi) in adults with central nervous system (cns) recurrence of leukemia

Purpose: Although CNS prophylaxis has reduced the incidence of CNS relapse, a poor prognostic feature, it still occurs in 5-10% of cases resulting in a median survival of six months. CSI has been shown to improve survival in children with a CNS relapse of acute lymphocytic leukemia (ALL). However, the role of CSI in adults with a CNS relapse of leukemia is unknown and is the focus of this study. Methods: A retrospective review of adult patients treated with CSI for CNS recurrence of leukemia identified 16 patients treated between 1986 and 2001. The median age was 34 years (15-58). The diagnoses were; 7 with acute myelogenous leukemia, 8 with ALL, and 1 with chronic myelogenous leukemia in blast crisis. All patients were in a complete remission prior to the CNS relapse. Eleven patients had an isolated CNS relapse; 5 patients had concurrent disease identified in the blood/bone marrow. The median dose was 24Gy (18-34.5) to the cranium and 18Gy (15-30) to the spine. The median fraction size was l.SGy (1.5-2.0) to the cranium and l.SGy (1.5-2.0) to the spine. Fifteen patients were also treated with intrathecal chemotherapy. Results: One patient failed to complete treatment due to disease progression. Thirteen patients achieved a complete response in the cerebrospinal fluid (CSF). The median time to progression was 3 months from the first day of CS1 and 8 months from CNS relapse. The median survival was 4 months and 9 months respectively. There were no CNS failures, 11 bone marrow failures, 2 without relapse at over five years, and 3 deaths without a documented site of failure. Thirteen patients had persistently negative CSF to death or last followup. Conclusion: CSI with or without intrathecal chemotherapy is effective at eliminating leukemia in the craniospinal axis. However, eradication of disease in the CNS was not effective at preventing recurrence in the bone marrow, and despite improved control in the CNS, adult patients with a CNS recurrence still have a poor prognosis.