title: Feasibility and outcome of re-irradiation in the treatment of multiply recurrent pituitary adenomas.
abstract: OBJECTIVE
  This study evaluates the toxicity and outcomes of re-irradiation to the sella for pituitary adenomas.
  
  
  METHODS
  Patients diagnosed with a pituitary adenoma and treated with two or more courses of radiation treatment (RT) to the sella were retrospectively analyzed for: initial diagnosis, including histological type and functional status; RT modality, technique, dose, and fractionation; treatment with surgery, endocrine agents, and chemotherapy; toxicity of RT including radiation-induced optic neuropathy, radionecrosis, and radiation-induced neoplasms; and outcomes including local control, distant metastasis, biochemical control of functional tumors, and vital status at last follow-up.
  
  
  RESULTS
  We identified 15 patients with non-functioning pituitary adenoma (n = 6), Cushing's disease (CD) (n = 5), acromegaly (n = 3), and prolactinoma (n = 1). Initial RT was delivered using opposed lateral fields in 8 (53%), intensity-modulated radiation therapy (IMRT) in 4 (27%), fractionated stereotactic radiation therapy (FSRT) in 1 (6.7%), and stereotactic radiosurgery (SRS) in 2. The median dose was 49.5 Gy for fractionated RT and 15-25 Gy for SRS. Re-irradiation was performed a median of 5.8 years after initial RT, and delivered using lateral opposed beams (n = 1), IMRT (n = 4), linear-accelerator based SRS (n = 3), FSRT (n = 3), gamma knife surgery (n = 2), and yttrium-90 brachytherapy (n = 1). The median dose of re-irradiation was 45 Gy (range 27.9-54 Gy) for fractionated RT and 18 Gy for SRS. Radiation-induced optic neuropathy (RION) was observed in 2 (13.3%) patients, 6 months and 14 years after re-irradiation; the 5-year rate of RION was 9 %. Temporal lobe necrosis (TLN) occurred in two patients (13.3%), both of whom had received SRS. The 2- and 5-year rates of TLN were 10 and 28%. Actuarial local control rates at 2 and 5 years were 80 and 58%, respectively. Biochemical remission occurred in one of three patients with CD. Four patients (27%) ultimately developed pituitary carcinoma.
  
  
  CONCLUSIONS
  Re-irradiation is a feasible treatment option for local control in patients with recalcitrant pituitary adenomas, with acceptable rates of RION and TLN given the lack of options that may be available otherwise. Re-irradiation, however, did not control hormonal hypersecretion.
authors.affiliation: Department of Radiation Oncology, University of Miami, Miami, FL, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Verma
authors.forename: Ian E
authors.initials: IE
authors.lastname: McCutcheon
authors.forename: Steven G
authors.initials: SG
authors.lastname: Waguespack
authors.forename: Anita
authors.initials: A
authors.lastname: Mahajan
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D018450:Disease Progression; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009336:Necrosis; D009362:Neoplasm Metastasis / Q000473:pathology; D009364:Neoplasm Recurrence, Local / Q000532:radiotherapy*; D009381:Neoplasms, Radiation-Induced / Q000453:epidemiology; D009901:Optic Nerve Diseases / Q000209:etiology; D010901:Pituitary Function Tests; D010911:Pituitary Neoplasms / Q000532:radiotherapy*; D011878:Radiotherapy / Q000009:adverse effects / Q000379:methods*; D012189:Retrospective Studies; D016879:Salvage Therapy; D016019:Survival Analysis; D016896:Treatment Outcome; D055815:Young Adult