title: Acromegaly: a single centre's experience of stereotactic radiosurgery and radiotherapy for growth hormone secreting pituitary tumours with the linear accelerator.
abstract: Primary treatment for growth-hormone secreting pituitary adenomas usually involves surgery, with treatment options for recurrent and persistent disease including repeat surgery, medication and radiation therapy. The majority of previously published series for radiation therapy in acromegaly in the past 20 years have been based on Gamma-Knife (Elekta, Stockholm, Sweden) surgery. To our knowledge, we present the largest series of linear accelerator-based treatment for this disease, with a review of 121 patients treated at our institution; since 1990, 86 patients underwent stereotactic radiosurgery (SRS), 10 patients underwent fractionated stereotactic radiotherapy (FSRT), and for the purposes of comparison we also reviewed 25 patients who underwent conventional radiotherapy prior to 1990. Tumour volume control in all three groups was excellent and consistent with previously reported literature - only three of 86 (4%) patients undergoing SRS had a documented increase in tumour size, and none of the patients undergoing FSRT had a documented increase in size following a median follow-up of 5.5 and 5.1 years for SRS and FSRT, respectively. Target growth hormone levels of <2.5 ng/mL were met by 12 of 86 (14%) of the SRS group, and by two of 10 (20%) in the FSRT group. Target insulin-like growth factor-1 levels of age and sex matched controls were achieved in 16 of 86 patients (18.6%) post-SRS and five of 10 patients (50%) post-FSRT. New hormonal deficits requiring replacement therapy were identified in 17 of 86 (19.8%) patients post-SRS which is consistent with previously published radiosurgical series. Identified non-hormonal morbidity was low (<5%).
authors.affiliation: Department of Radiation Oncology, The Prince of Wales Cancer Centre, Level 2, High Street, Randwick, NSW 2031, Australia.
authors.forename: P J
authors.initials: PJ
authors.lastname: Wilson
authors.forename: K J
authors.initials: KJ
authors.lastname: De-Loyde
authors.forename: J R
authors.initials: JR
authors.lastname: Williams
authors.forename: R I
authors.initials: RI
authors.lastname: Smee
mesh_terms: D000236:Adenoma / Q000532:radiotherapy* / Q000601:surgery*; D000328:Adult; D000368:Aged; D005260:Female; D013006:Growth Hormone / Q000097:blood; D049912:Growth Hormone-Secreting Pituitary Adenoma / Q000532:radiotherapy* / Q000601:surgery*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D053208:Kaplan-Meier Estimate; D008297:Male; D008875:Middle Aged; D016634:Radiosurgery; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D007334:Insulin-Like Growth Factor I; D013006:Growth Hormone
keywords: Acromegaly; Endocrine replacement therapy; Pituitary tumours; Radiation therapy; Surgery; Tumour control