Outcomes for Pituitary Adenoma Patients Treated with Linac-Based Stereotactic Radiosurgery and Radiotherapy: a Long Term Experience in Thailand

Background: The study analyzed the long term clinical outcomes of pituitary adenoma cases treated withthe first Thailand installation of a dedicated Linac-based stereotactic radiation machine (X-Knife). Materialsand
Methods: A retrospective review of 115 consecutive pituitary adenoma patients treated with X-Knife at theFaculty of Medicine, Ramathibodi Hospital, Bangkok, Thailand from 1997 to 2003 was performed. Stereotacticradiosurgery (SRS) was selected for 21 patients (18%) including those with small tumors (≤3cm) located ≥ 5 mm.from the optic apparatus, whereas the remaining 94 patients (82%) were treated with fractionated stereotacticradiotherapy (FSRT).
Results: With a median follow-up time of 62 months (range, 21-179), the six-year progressionfree survival was 95% (93% for SRS and 95% for FSRT). The overall hormone normalization at 3 and 5 yearswas 20% and 30%, respectively, with average time required for normalization of approximately 16 months forSRS and 20 months for FSRT. The incidence of new hypopituitarism was 10% in the SRS group and 9% in theFSRT group. Four patients (5%) developed optic neuropathy (1 in the SRS group and 3 in the FSRT group ).
Conclusions: Linac-based SRS and FSRT achieved similar high local control rates with few complications inpituitary adenoma cases. However, further well designed, randomized comparative studies between SRS versusFSRT particularly focusing on hormone normalization rates are required.