Introduction and aim of work: Neurocognitive late effects are common sequelae of cancer in children, especially in those who have undergone treatment for brain tumors or in those receiving prophylactic cranial radiation or intrathecal chemotherapy therapy to treat leukemia and non Hodgkin lymphoma (NHL). As NHL represents 8–10% of all malignancies in children between 5–19 years of age (Cairo, 2009)  and all NHL children receive intrathecal methotrexate as therapy or prophylaxis so we studied effect of intrathecal methotrexate in NHL treated children in their cognitive function and compare it with normal children, also we studied effect of some risk factors (age at disease onset and number of intrathecal injections) on the affected intelligence subscales and lastly a suitable and applicable model to evaluate neurocognitive function was done.
Patients and methods: The study included 25 NHL treated children and 10 children as controls, all children are subjected to some specific neurocognitive tests and sheet for assessment of neurocognitive function as complementary study.
Result: It showed that total IQ score, verbal and quantitative subscales are significantly affected in NHL patients and verbal subscale is more affected in children who began treatment at younger age