title: Target delineation and optimal radiosurgical dose for pituitary tumors.
abstract: Stereotactic radiosurgery (SRS) delivered as either single-fraction or multi-fraction SRS (2-5 fractions) is frequently employed in patients with residual or recurrent pituitary adenoma. The most common delivery systems used for SRS include the cobalt-60 system Gamma Knife, the CyberKnife (CK) robotic radiosurgery system, or a modified conventional radiotherapy machine (linear accelerator, LINAC). Tumor control and normalization of hormone hypersecretion have been reported in 75-100 % and 25-80 % of patients, respectively. Hypopituitarism is the most commonly reported late complication of radiation treatment, whereas other toxicities occur less frequently. We have provided an overview of the recent available literature on SRS in patients with a pituitary adenoma. Critical aspects of pituitary irradiation, including target delineation and doses to organs at risk, optimal radiation dose, as well as the long-term efficacy and toxicity of SRS for either nonfunctioning or secreting pituitary adenomas are discussed. Single-fraction SRS represents an effective treatment for patients with a pituitary adenoma; however, caution should be used for lesions > 2.5-3 cm in size and/or involving the anterior optic pathway. Future studies will be necessary to optimize target doses and critical organ dose constrains in order to reduce the long-term toxicity of treatments while maintaining high efficacy.
authors.affiliation: Unit of Radiation Oncology, Sant' Andrea Hospital, University Sapienza, Rome, Italy. giuseppeminniti@libero.it.|IRCCS Neuromed, Pozzilli (IS), Italy. giuseppeminniti@libero.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Minniti
authors.affiliation: Unit of Radiation Oncology, Sant' Andrea Hospital, University Sapienza, Rome, Italy.
authors.forename: Mattia Falchetto
authors.initials: MF
authors.lastname: Osti
authors.affiliation: Department of Radiation Oncology, LMU Munich, Munich, Germany.
authors.forename: Maximillian
authors.initials: M
authors.lastname: Niyazi
mesh_terms: D000236:Adenoma / Q000532:radiotherapy; D001933:Brain Stem / Q000528:radiation effects; D006624:Hippocampus / Q000528:radiation effects; D006801:Humans; D007018:Hypopituitarism / Q000209:etiology; D009901:Optic Nerve Diseases / Q000209:etiology; D047748:Pituitary ACTH Hypersecretion / Q000532:radiotherapy; D010911:Pituitary Neoplasms / Q000532:radiotherapy*; D016634:Radiosurgery / Q000009:adverse effects / Q000379:methods*; D011879:Radiotherapy Dosage
keywords: Acromegaly; Cushing’s disease; Fractionated stereotactic radiotherapy; Pituitary adenoma; Radiosurgery; Target delineation