Dementia in cancer patients undergoing chemotherapy: implication of free radical injury and relevance to Alzheimer disease.

A number of neurological disorders including Alzheimer and Parkinson disease have been suggested to be caused by processes leading to lipid peroxidation. Other theories implicate the accumulation of damaged DNA, resulting from a defect in DNA repair, in the pathogenesis of these disorders. I suggest that these theories might be related, since the hydroxy free radical is known to attack DNA and inactivate enzymes so that oxygen metabolism has the potential to interfere with the maintenance of genomic integrity. Since psychometric intelligence correlates highly with erythrocyte glutathione peroxidase activity, a free radical scavenger, perhaps this might explain the marked intellectual impairment caused by chemotherapeutic agents such as cytosine arabinoside, as well as in Alzheimer disease.