Vincristine induced neurotoxicity in cancer patients

Ten out of 20 children, treated with usual doses of vincristine for various types of childhood cancers, developed neurotoxicity during treatment. Peripheral neurotoxicity (mixed motor-sensory 4/10, pure motor 3/10, pure sensory 3/10) was seen in the form of weakness of lower limbs, areflexia, neuropathic pain, or sensory loss. Autonomic neuropathy presented as constipation and urinary retention in 2 children, while 2 children developed encephalopathy in form of seizures, confusion, aphasia, and transient blindness. In children with severe neuropathy, vincristine administration was withheld/dose reduced till clinical improvement started, which took about 2-3 weeks time. Nerve conduction velocity showed motor-sensory axonal polyneuropathy. Electrophysiological abnormalities were found to persist even six months after clinical recovery in children with neurotoxicity. We found a relatively higher incidence of vincristine induced neuropathy in Indian children, which was probably due to coexistence of severe malnutrition in them.