Electrophysiological consequences of vincristine contained chemotherapy in children: A cohort study

Abstract

Vincristine is commonly used in treatment of acute lymphoblastic leukemia (ALL), and peripheral neuropathy is its dose-related toxicity. Motor impairment, specifically muscle weakness is the most severe manifestation of neuropathy. This study aimed at evaluation of the electrophysiological consequences of vincristine-contained chemotherapy in children. In a prospective cohort setting, the electrophysiological studies was performed in 42 children (25 cases of ALL, 17 cases of non-ALL malignancies) at the electrodiagnostic ward of Tabriz Children Hospital, before and five weeks after chemotherapy. Changes in the electrodiagnostic parameters before and after administration of vincristine, as well as its relation with drug dose were determined. Twenty-five children with ALL with the mean age of 6.08 years, and 17 children with other malignancies with the mean age of 6.54 years during a 12-months period were enrolled. In the ALL group, there was no significant change in motor and sensory nerve conduction velocity and amplitude of sensory nerve action potential after five weeks. However, the amplitude of compound muscle action potential (CMAP) was significantly decreased both in upper and lower extremities. Decreased CMAP amplitude was detected in 96% of the ALL cases after induction, majority moderate (70.8%). Sixteen (66.7%) patients suffered from gait abnormality as well. In the non-ALL group, five (29.4%) cases were treated with regimen similar to that employed in the ALL group (group B) and 12 (70.6%) patients were treated with other regimens (group C). Neuropathy was detected in nine (52.9%) patients, five (100%) cases in group B and four (33.3%) cases in group C. In group B, mild, moderate and severe neuropathies were detected in one (20%), three (60%) and one (20%) cases, respectively. Patients in group C were affected with mild neuropathy. Generally, there was a significant decrease of CMAP amplitude with increasing dose of vincristine. This study showed that the electrophysiological changes due to weekly administration of vincristine are common in children with ALL during the induction phase, which usually presented in the form of decreased CMAP amplitude (motor-axonal neuropathy), however routine sensory studies were normal. Gait abnormality is accompanied in 66.7% of ALL cases.

Keywords

Vincristine - acute lymphoblastic leukemia - neuropathy - children