Central nervous system relapse prophylaxis in acute lymphoblastic leukemia (ALL) intrathecal chemotherapy with and without cranial irradiation

Background: Central Nervous System (CNS) relapse in acute lymphoblastic leukemia was significantly decreased due to the use of new chemotherapyeutic agents, Intrathecal chemotherapy and cranial irradiation. The purpose of this study was to compare the effectiveness of intrathecal (IT) CNS chemotherapy alone versus combination of IT chemotherapy with cranial irradiation for prevention of CNS relapse.Methods: From 1998 to 2008 ninety eight cases of acute lymphoblastic leukemia (ALL) admitted in Amirkola Children Hospital were enrolled in this study. The chemotherapy regimen was on the basis of protocol of BFM-79. CNS prophylaxis consisted of intrathecal Cytarabin or Methotrexate, in addition to cranial irradiation for patients more than 3 years old. We assessed the incidence of CNC relapses over 10 years of CNS prophylaxis regimen. Results: From ninety eight cases, 53 were females and 45 were males. Twenty six were below 3 years old and seventy two were above 3 years old (p<0.05). For 10 years of study for the 72 cases who were more than 3 years old and had received prophylactic cranial irradiation CNS relapse did not happen. Among the 26 cases below 3 years old who didnot receive prophylactic cranial irradiation CNS relapse for one case happened (3.8%) (p<0.05). Conclusion: The results show that the combination of prophylactic CNS irradiation and intrathecal chemotherapy is effective in prophylaxis of CNS relapse in ALL.