[Pituitary radiotherapy. Current data and future prospects].
Some technical improvements have allowed to minimize the frequency of severe complications following fractionated pituitary conventional radiotherapy, without altering its efficiency. "Conformational" radiotherapy is currently under development, aiming at the best fitting of the tumor borders to the irradiation zone, by the means of stereotactic imaging. More recently, radiosurgery has been proposed for pituitary adenomas. It consists in a single high radiation dose to the tumor, by the means of either cobalt minibeams (Gamma Unit) or photon beams from a linear particle accelerator. These techniques require the use of a stereotactic frame and precise 3D imaging in order to tightly superimpose the target volume to the reference isodose. They must not be viewed as an alternative to conventional radiotherapy. They can be applied only to small lesions (less than 20 mm in their maximal axis) which are distant (> 5 mm) from the optic chiasma and nerves. Their efficiency is similar to the one of fractionated conventional radiotherapy, with a shorter response time. In conclusion, radiotherapy can be used safely for pituitary adenomas. It remains however a second line treatment, when surgery has been incomplete and when a simple, effective and inexpensive medical treatment is not possible.