Outcome of fractionated stereotactic radiotherapy in patients with pituitary adenomas resistant to conventional treatments: a 5·25‐year follow‐up study

Summary Objective  To investigate the long-term outcome of fractionated stereotactic radiotherapy (FSRT) [45 Gy (range 45–54) in 25 fractions] in patients with pituitary adenomas characterized by tumour progression or hormonally active disease despite surgery and/or medical therapy. Design  This was an observational follow-up study of 5·25 years (median; range 1·7–10·4). Patients and measurements  Pituitary tumour volume, visual acuity/fields, hypersecretion, hypopituitarism, cerebrovascular disease, second brain tumours and mortality were examined at regular intervals after FSRT in 30 patients with pituitary adenomas (20 nonfunctioning macroadenomas, 10 functioning). Prior to FSRT, 83% had been operated 1–3 times, 47% had visual field deficits/impaired vision and 50% pituitary dysfunction. Progressive disease, stable disease, partial and complete tumour response were defined by MRI. Results  Tumour growth control was 100%. At the end of follow-up, 30% had stable disease, 60% partial and 10% complete tumour response. Visual function was preserved and 36% of patients with prior field deficits improved. GH decreased from 4·2 (range, 2·3–6·5) to 1·1 (range, 0·5–1·5) μg/l (P < 0·001) in patients with acromegaly, and medical therapy could be reduced. In large prolactinomas, partial response or complete tumour response was achieved. FSRT was well tolerated. Pituitary function remained normal in 27%, 33% of patients had stable dysfunction, 17% deteriorated further and 23% developed new dysfunction. There were no cerebrovascular events, second brain tumours or FSRT-related deaths. Conclusion  According to this long-term follow-up study, FSRT is an efficient and safe adjuvant therapy for pituitary adenomas refractory to conventional treatments.