Cognitive function of patients with nasopharyngeal carcinoma with and without temporal lobe radionecrosis

Background: Radiotherapy is the primary treatment for nasopharyngeal carcin oma, and temporal lobe necrosis is observed in about 7% of patients after r adiotherapy. Although some studies reported that these patients demonstrate d cognitive impairment after radiotherapy, it is still unclear if the cogni tive deficits are related to the radiation exposure or the radiation-induce d necrosis. Objective: To compare the cognitive function of patients with and without t emporal lobe necrosis after radiotherapy for nasopharyngeal carcinoma. Methods: A comprehensive neuropsychological battery was administered to 53 patients with nasopharyngeal carcinoma who had completed their radiotherapy at least 1 year previously. As evidenced by magnetic resonance imaging, 31 patients developed necrosis after treatment. Thirty-one age- and education -matched individuals were recruited as normal control subjects. Results: Whereas the performance of patients without temporal lobe necrosis was similar to that of normal control subjects, patients with temporal lob e necrosis demonstrated significant impairment on tests of verbal (P<.001) and visual memory (range, P<.001 to P=.03), language (range, P<.001 to P=.0 1), motor ability (P=.02), planning (P=.02), cognitive ability (P=.007), an d abstract thinking (range, P=.009 to P=.04). However, the performance of p atients with necrosis on tests of general intelligence (range, P=.08 to P=. 15), attention (range, P=.06 to P=.55), and visual abilities (range, P=.06 to P=.47) was not significantly different from that of normal control subje cts and patients without necrosis. Conclusions: Radiotherapy for nasopharyngeal carcinoma seemed to have adver se but insignificant effects on the cognitive functions of the patients. Ho wever, for patients who developed temporal lobe necrosis after radiotherapy , memory, language, motor ability, and executive functions were significant ly impaired, although their general intelligence remained relatively intact .