title: Impact of radionecrosis on cognitive dysfunction in patients after radiotherapy for nasopharyngeal carcinoma.
abstract: BACKGROUND
  Cognitive dysfunction is common in patients who develop radionecrosis after receiving radiotherapy for nasopharyngeal carcinoma (NPC). However, the impact of the location and volume of radionecrosis on cognitive dysfunction remains unclear. The authors found a significant association between the severity of cognitive impairment and the volume of radionecrosis; in turn, the volume of radionecrosis was affected by patient age at time radiotherapy was completed.
  
  
  METHODS
  Fifty patients with NPC who received radiotherapy were evaluated by a battery of neuropsychologic tests of cognitive function. The brain lesion volume was quantified, and the lesion locations were identified by standardized brain templates. The results of the neuropsychologic tests were correlated with lesion volume. Gender, education, age at the completion of radiotherapy, brain volume, total dose, and fractional dose were evaluated as risk factors for lesion volume.
  
  
  RESULTS
  Lesion volume was correlated significantly with the severity of cognitive deficits. Larger left-hemisphere lesions were correlated with lower verbal memory (from P < 0.001 to P = 0.008) and language abilities (from P = 0.001 to P = 0.018), whereas larger right-hemisphere lesions were associated with worse visual memory (from P = 0.009 to P = 0.039). Finally, patients who received radiotherapy at a younger age had smaller lesion volumes (P < 0.001).
  
  
  CONCLUSIONS
  The volume and location of radionecrosis had an influential impact on the pattern of cognitive impairment found in patients with NPC, and patient age at the time radiotherapy was completed appeared to affect the volume of radionecrosis found after radiotherapy.
authors.affiliation: Department of Psychology, Chinese University of Hong Kong, Hong Kong SAR, China.
authors.forename: Mei-Chun
authors.initials: MC
authors.lastname: Cheung
authors.forename: Agnes S
authors.initials: AS
authors.lastname: Chan
authors.forename: Stephen C
authors.initials: SC
authors.lastname: Law
authors.forename: John H
authors.initials: JH
authors.lastname: Chan
authors.forename: Vincent K
authors.initials: VK
authors.lastname: Tse
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000473:pathology / Q000528:radiation effects*; D003072:Cognition Disorders / Q000175:diagnosis / Q000209:etiology*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007360:Intelligence; D007858:Learning / Q000502:physiology; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000209:etiology; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000532:radiotherapy*; D009336:Necrosis; D009468:Neuromuscular Diseases; D009483:Neuropsychological Tests; D011597:Psychomotor Performance; D011832:Radiation Injuries / Q000175:diagnosis / Q000209:etiology*