The Effect of Intensive Intrathecal Chemotherapy on Prognosis of Childhood Lymphoblastic Leukemia with Central Nervous System Involvement: A 20-Year Experience

Primary central nervous system involvement and central nervous system relapse are poor prognostic events in acute lymphoblastic leukemia. Due to severe skeletal and endocrine complications of craniospinal radiotherapy, only cranial radiotherapy is advisable. However only 15% of the cases with central nervous system relapse may remain in remission; a second central nervous system or bone marrow relapse is common. Prevention of central nervous system relapse is an extremely important way to decrease both mortality and morbidity in childhood leukemia.
This prospective study was conducted from June 1995 to May 2014. A total of 90 children diagnosed with acute lymphoblastic leukemia enrolled in this study following parental informed consent. There were 30 children with primary central nervous system involvement and 60 that had central nervous system relapse due to acute lymphoblastic leukemia. Patients were randomly divided into two groups: 30 patients in group A (control group) received triple intrathecal injections every 2 months according to high risk acute lymphoblastic leukemia protocols for a total of three years. Group A was divided into the following subgroups: A1 (primary central nervous system involvement; n=15) and A2 (central nervous system relapse; n=15). Group B (case group) comprised 60 patients that received additional triple intrathecal injections during the fourth and fifth years (2 years after discontinuation of maintenance chemotherapy). Group B was subdivided as follows: B1 (primary central nervous system involvement; n=20) and B2 (central nervous system relapse; n=40). For each patient in group A, two age and sex matched patients in group B were enrolled. Patients were followed for 2-15 years.
From 15 patients in group A1 (control with primary central nervous system involvement), there were 5 central nervous system relapses, 3 bone marrow relapses, and 2 deaths. Boys had more relapses and deaths than girls (chi square: 15.63; P Extended intrathecal injections after discontinuation of maintenance
chemotherapy is advisable for cases with primary central nervous system involvement and central nervous system relapses. However, we propose that national and international studies with greater number of patients should be conducted.