Clinical patterns and biological correlates of cognitive dysfunction associated with cancer therapy.

Standard oncological therapies, such as chemotherapy and cranial radiotherapy, frequently result in a spectrum of neurocognitive deficits that includes impaired learning, memory, attention, and speed of information processing. In addition to classical mechanisms of neurotoxicity associated with chemo- and radiotherapy, such as radiation necrosis and leukoencephalopathy, damage to dynamic progenitor cell populations in the brain is emerging as an important etiologic factor. Radiation- and chemotherapy-induced damage to progenitor populations responsible for maintenance of white matter integrity and adult hippocampal neurogenesis is now believed to play a major role in the neurocognitive impairment many cancer survivors experience.