title: Treatment of acromegaly patients with risk-adapted single or fractionated stereotactic high-precision radiotherapy: High local control and low toxicity in a pooled series.
abstract: OBJECTIVE
  The purpose of this work was to evaluate a prospectively initiated two-center protocol of risk-adapted stereotactic radiosurgery (SRS) or stereotactic radiotherapy (SRT) in patients with acromegaly.
  
  
  METHODS
  In total 35 patients (16 men/19 women, mean age 54 years) were prospectively included in a treatment protocol of SRS [planning target volume (PTV < 4 ccm, > 2 mm to optic pathways = low risk] or SRT (PTV ≥ 4 ccm, ≤ 2 mm to optic pathways = high risk). The mean tumor volume was 3.71 ccm (range: 0.11-22.10 ccm). Based on the protocol guidelines, 21 patients were treated with SRS and 12 patients with SRT, 2 patients received both consecutively.
  
  
  RESULTS
  The median follow-up (FU) reached 8 years with a 5-year overall survival (OS) of 87.3% [confidence interval (CI): 70.8-95.6%] and 5-year local control rate of 97.1% (CI: 83.4-99.8%). Almost 80% (28/35) presented tumor shrinkage during FU. Endocrinological cure was achieved in 23% and IGF-1 normalization with reduced medication was achieved in 40% of all patients. An endocrinological response was generally achieved within the first 3 years, but endocrinological cure can require more than 8 years. A new adrenocorticotropic hypopituitarism occurred in 13 patients (46.4%). A new visual field disorder and a new oculomotor palsy occurred in 1 patient, respectively. Patients with occurrence of visual/neurological impairments had a longer FU (p = 0.049).
  
  
  CONCLUSIONS
  Our SRS/SRT protocol proved to be safe and successful in terms of tumor control and protection of the visual system. The timing and rate of endocrine improvements are difficult to predict. One has to accept an unavoidable rate of additional adrenocorticotropic hypopituitarism in the long term.
authors.affiliation: Department of Radiosurgery and Stereotactic Radiotherapy, Mediclin Robert Janker Clinic and MediClin MVZ Bonn, Villenstrasse 8, 53129, Bonn, Germany, Jan.Bostroem@mediclin.de.
authors.forename: Jan Patrick
authors.initials: JP
authors.lastname: Boström
authors.forename: Thomas
authors.initials: T
authors.lastname: Kinfe
authors.forename: Almuth
authors.initials: A
authors.lastname: Meyer
authors.forename: Bogdan
authors.initials: B
authors.lastname: Pintea
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Gerlach
authors.forename: Gunnar
authors.initials: G
authors.lastname: Surber
authors.forename: Guido
authors.initials: G
authors.lastname: Lammering
authors.forename: Klaus
authors.initials: K
authors.lastname: Hamm
mesh_terms: D000172:Acromegaly / Q000209:etiology / Q000601:surgery*; D000236:Adenoma / Q000150:complications / Q000601:surgery*; D000328:Adult; D000368:Aged; D019583:Dose Fractionation, Radiation; D005260:Female; D005858:Germany; D006801:Humans; D008297:Male; D008875:Middle Aged; D010911:Pituitary Neoplasms / Q000150:complications / Q000601:surgery*; D011832:Radiation Injuries / Q000209:etiology* / Q000517:prevention & control; D016634:Radiosurgery / Q000009:adverse effects* / Q000379:methods*; D016896:Treatment Outcome