Radiation techniques in aggressive pituitary tumours and carcinomas

Defining the role of radiation techniques in treatment of aggressive pituitary tumours and carcinomas is a difficult task: indeed, studies reported in the literature on this topic can probably be counted on the fingers of one hand. To try to better define these roles, it is thus necessary to extrapolate based on anti-secretory and anti-tumor efficacy reported in studies on non-selected pituitary tumours, regardless of their pathological status and intrinsic aggressiveness. Generally, radiation techniques are delivered as part of a multimodal treatment, usually with the primary aim of controlling tumor volume. Side-effects need to be divided into short and long-term, also depending on the overall prognosis of the tumour, since hypopituitarism will likely appear in the majority of patients, extra-pituitary side-effects, which have been reported after a significant delay after the procedure, can only be considered in patients with less aggressive pituitary tumours. In this review, we will first detail the different modalities of radiation techniques and the inherent limits of each technique depending on the volume and the localization of the tumour. We will then discuss the anti-tumour and anti-secretory efficacy of radiation techniques in aggressive pituitary tumors, either as a single treatment or as part of a multimodal treatment. Finally we will discuss the technique-specific side-effects.