The effects of radiotherapy on neurocognitive function in patients treated for non-functioning pituitary adenoma
Alana Tooze, Neil Gittoes, Chris Jones & Andrew Toogood
Background: Surgery, sometimes supported by adjunctive radiotherapy (RT) are the treatments of choice for patients with non-functioning pituitary adenomas (NFA). Previous studies have implicated these treatments in deficits of cognitive function, particularly memory and executive functioning, although this research has often been confounded by the inclusion of patients with hormone producing tumours. The aim of this study was to determine the impact of RT on psychometric function in patients treated for NFA. This will give clinicians and patients a better understanding as to the risks and benefits of treatment.
Methods: 25 patients treated for NFA (10 surgery only (5 male), 15 surgery and radiotherapy (9 male)) underwent psychometric evaluation using the Wechsler Adult Intelligence Scale, Wechsler Memory Scale, Delis-Kaplan Executive Functioning System and Wechsler Adult Test of Reading. The study was approved by the local ethics committee.
Results: Overall performance during the tests was similar in both groups. However, by using the patients IQ as an indication of global functioning to compare the other tests against, patients treated with RT demonstrated significant impairment in cognitive function. Patients treated with surgery and RT had significantly poorer immediate memory (P=0.017) and visual memory for visually presented stimuli (P=0.002). Their visual immediate recall was also significantly worse than their delayed recall for the same stimuli (P=0.003). These changes were not seen in patients treated with surgery alone. Delayed recall of information (30 minutes after presentation) was comensurate with the patients IQ in both groups. Working memory was also unaffected when compared to IQ.
Conclusions: These data indicate that patients treated with RT in addition to surgery for NFAs have a deficit in cognitive function, specifically in immediate memory which may manifest itself as difficulty in learning new information. These important observations will help clinicians counsel patients more accurately when considering RT.