Neurocognitive changes after radiation to the pituitary region

Radiotherapy has a key role in the management of pituitary tumors as well as other benign and malignant diseases that occur anatomically close to the pituitary gland. The role of radiotherapy in these diseases is outlined in this review, along with some of the key technical features of the different radiotherapy treatment platforms, including proton beam therapy. Some of the key concepts of radiobiology are discussed, including the role of radiotherapy dose fractionation to allow for repair within normal tissues adjacent to the tumor target. Despite the technological advances seen in radiotherapy planning and delivery, the late effects of radiotherapy to the brain remain problematic, particularly in patients with otherwise good prognosis. Neurocognitive changes are a key feature of these late treatment effects and are highly predictive of disability and reduced quality of life. In light of this, we present a narrative review of published studies of radiotherapy-induced neurocognitive decline in pituitary patients. We found that while only a minority of studies noted an additional effect of radiotherapy on cognition after surgery, methodological issues are present for many negative findings. These include lenient assessment techniques and potentially unrepresentative samples. Arising from this, we present a framework for the assessment of neurocognitive decline in pituitary patients, which can be applied both in future research studies and clinical settings.