[Radiotherapy and radiosurgery of pituitary adenomas]

There are two principal types of treatment for pituitary adenomas: fractionated conventional radiation therapy, based on biological selectivity, and radiosurgery, which is delivered in a single dose, based on anatomic selectivity and indicated preferentially for small tumors sufficiently distant from the optic chiasm. Conventional radiation therapy is effective against secretion in 60-80% of cases and radiosurgery in 40-50%, depending on the type of secretion. Maximum antisecretory efficacy is not reached immediately: this delay is longer for conventional radiation therapy (5-10 years) than for radiosurgery (2-3 years). In both cases, antisecretory treatment must be started, while awaiting remission. Radiation therapy and radiosurgery make it possible to stabilize or diminish tumor volume in 70-100% of cases. This is especially useful in the case of an active residue after surgery for non-secreting adenoma, but the long-term side effects of radiation must be borne in mind. The principal side effect is the onset of a pituitary deficiency (in more than 50% of cases after radiation therapy, 20% after radiosurgery). The risk increases with time since treatment. Other very long-term side effects have been described with radiation therapy: radiation-induced tumors, cerebral necrosis, strokes, etc. The role of radiosurgery and radiation therapy is growing ever more limited, because of the increasing efficacy of drug treatments and the excellent surgical results of experienced teams.