Abnormal visual-evoked potentials in leukemic children after cranial radiation.

Area of Science:

• Neuroscience
• Pediatric Oncology
• Ophthalmology

Background:

• Children undergoing treatment for leukemia or solid tumors often receive central nervous system (CNS) prophylaxis.
• Subclinical neurological deficits, such as optic pathway demyelination, may occur after such treatments.
• Visual-evoked potentials (VEPs) are a non-invasive tool to assess the integrity of the visual pathway.

Purpose of the Study:

• To investigate subclinical demyelination of the optic pathway in asymptomatic children with leukemia or solid tumors in remission.
• To evaluate the impact of central nervous system prophylaxis, particularly cranial radiation, on visual pathway function using VEPs.

Main Methods:

• A cohort of 55 asymptomatic children in remission from leukemia or solid tumors were studied.
• Visual-evoked potentials (VEPs) were recorded to measure visual pathway conduction.
• Patients were categorized into groups based on treatment received, including cranial radiation (CR), maintenance therapy, and those without CR.

Main Results:

• Increased VEP latency, indicative of slowed conduction, was observed in 10 out of 11 patients after cranial radiation.
• Abnormal VEP latency was found in 33% and 31% of patients receiving maintenance or off-therapy ALL treatment, respectively.
• Patients who did not receive cranial radiation showed normal VEP latency, even with intrathecal methotrexate administration.

Conclusions:

• Cranial radiation is associated with a high proportion of slowed optic pathway conduction, likely due to demyelination.
• VEP testing can detect subclinical visual pathway abnormalities following cancer treatment in children.
• Further long-term follow-up is necessary to determine the clinical significance of these VEP findings.