Cognitive function before and after intensity-modulated radiation therapy in patients with nasopharyngeal carcinoma: a prospective study.
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.
Hsiao
Kuan-Yin
KY
Department of Radiation Oncology, E-Da Hospital, Kaohsiung, Taiwan.
Yeh
Shyh-An
SA
Chang
Chiung-Chih
CC
Tsai
Pei-Chien
PC
Wu
Jia-Ming
JM
Gau
Jhy-Shyan
JS
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