title: Cognitive function before and after intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma: a prospective study.
abstract: OBJECTIVE
  To evaluate the effects of radiation therapy (RT) on neurocognitive function in patients with nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  Thirty patients with NPC treated with intensity-modulated RT were included. Dose-volume histograms of the temporal lobes were obtained in every patient. Neurocognitive tests were administered individually to each patient 1 day before initiation of RT and at least 12 months after completion of RT. Cognitive functioning status was evaluated as change in scores over time.
  
  
  RESULTS
  Among the total of 30 patients, 23 patients (76.7%) had significantly lower post-RT cognitive functioning scores compared with their pre-RT scores (p = 0.033). The cognitive functioning scores had significantly declined in the domains of short-term memory, language abilities, and list-generating fluency (p = 0.020, 0.023, and 0.001, respectively). Compared with patients with a mean dose to the temporal lobes of 36 Gy or less, patients with a mean dose of greater than 36 Gy had a significantly greater reduction in cognitive functioning scores (p = 0.017). Patients in whom V60 of the temporal lobes (i.e., the percentage of the temporal lobe volume that had received >60 Gy) was greater than 10% also had a greater reduction in cognitive functioning scores than those in whom V60 was 10% or less (p = 0.039).
  
  
  CONCLUSIONS
  The results of our study indicated that RT could have deleterious effects on cognitive function in patients with NPC. Efforts should be made to reduce the radiation dose and irradiated volume of temporal lobes without compromising the coverage of target volume.
authors.affiliation: Department of Radiation Oncology, E-Da Hospital, Kaohsiung, Taiwan.
authors.forename: Kuan-Yin
authors.initials: KY
authors.lastname: Hsiao
authors.forename: Shyh-An
authors.initials: SA
authors.lastname: Yeh
authors.forename: Chiung-Chih
authors.initials: CC
authors.lastname: Chang
authors.forename: Pei-Chien
authors.initials: PC
authors.lastname: Tsai
authors.forename: Jia-Ming
authors.initials: JM
authors.lastname: Wu
authors.forename: Jhy-Shyan
authors.initials: JS
authors.lastname: Gau
mesh_terms: D003071:Cognition / Q000528:radiation effects; D003072:Cognition Disorders / Q000209:etiology*; D005260:Female; D006801:Humans; D007806:Language Disorders / Q000209:etiology; D008297:Male; D008569:Memory Disorders / Q000209:etiology*; D008570:Memory, Short-Term / Q000528:radiation effects; D008875:Middle Aged; D009303:Nasopharyngeal Neoplasms / Q000473:pathology / Q000532:radiotherapy*; D011446:Prospective Studies; D050397:Radiotherapy, Intensity-Modulated / Q000009:adverse effects*; D013702:Temporal Lobe / Q000528:radiation effects; D047368:Tumor Burden