Intermediate dose methotrexate versus cranial irradiation for central nervous system (C.N.S)‎ Prophylaxis in high risk childhood acute lymphoblastic leukemia (A.L.L.)‎

الملخص EN

The use of cranial irradiation for central nervous system prophylaxis in acute imphoblastic leukaemia had been debated due to its long term neurotoxicity.

An alternative method of prophylaxis using different doses of systemic methotrexate and an extended intrathecal chemotherapy are now being tried.

This study is a retrospective analysis of treatment results of forty-six newly diagnosed pediatric acute lymphoblastic leukaemia patients presented to Abul Reesh Pediatric Hospital and referred to the oncology department of Kasr El-Aini Hospital, Cairo University, during the period from February 1994 until August 1997.

Two different methods of central nervous system prophylaxis were applied, the first method (group I) was applied on 15 patients where an intermediate dose of systemic methotrexate (200 mg / m2 I.V.

shot followed by 800 mg / m2 I.V.

24 hour infusion) was given for 6 doses (separated by 3 weeks intervals) together with triple intrathecal chemotherapy for 5 doses during the consolidation phase and followed by another 5 doses during maintenance phase.

The second method (group II) was applied on 31 patients where whole cranial irradiation was given at radiation dose of 1800c Gy in 10 treatments over two weeks using Cobalt 60 machine and intrathecal chemotherapy was given only for 3 times during induction.

By the end of January 1999, full analysis of clinical data of both groups of patients was done, where they were found to be comparable as regards their age, sex, time before clinical presentation, clinical symptoms and signs and haematological profiles.

After a median follow up of 25 months, the two groups of patients were not statistically different as regards their complete remission rate (100 % in group I and 96.7 % in group II), isolated central nervous system relapse rate [1 / 15 (6.7 %) in group I and 2 / 31 (6.5 %) in group II], isolated systemic relapse rate [3 / 15 (20 %) in group I and 11 / 31 (35.5 %) in group II] and combined systemic and central nervous system relapse rates [2 / 15 (13.3 %) in group I and 3 / 31 (9.7 %) in group II].

As regards survival figures, the two groups were not statistically different either in their 2-year isolated central nervous system relapse free survival rates (90 % in group I and 87 % in group II), their 2-year isolated systemic relapse free survival rates (85.7 % in group I and 60 % in group II) or combined central nervous system and systemic relapse free survival rates (83.3 % in group I and 90 % in group II) as regards event free survival rates.

The 2-year event-free survival rate for group (I) was 64.3 % versus 47 % for group II the result being statistically insignificant.

As regards overall survival rates, the 2-year survival rate was 73.3 % for group I versus 48.2 % for group II the result being statistically insignificant.

Conclusion: Both modalities offer the same central nervous system prophylactic effect.