Modern techniques for pituitary radiotherapy

Abstract

Radiotherapy (RT) remains an effective treatment for residual or recurrent pituitary adenomas with excellent rates of tumour control and normalisation of excess hormone secretion. The main late toxicity is hypopituitarism: other side effects are rare. We discuss technical developments in the delivery of radiotherapy (stereotactic conformal radiotherapy (SCRT) and stereotactic radiosurgery (SRS)), all aiming to reduce the amount of normal brain receiving significant doses of radiation. We provide a comprehensive review of published data on outcome of conventional fractionated radiotherapy and modern RT techniques. SCRT is a suitable treatment technique for all sizes of pituitary adenoma and efficacy is comparable to conventional RT; the lack of long term follow up means that currently there is no information on potential reduction in the incidence of late radiation induced toxicity. Single fraction SRS can only be safely delivered to small tumours away from critical structures. There is no evidence that it produces faster decline of elevated hormone levels than fractionated treatment and is not associated with lesser morbidity.