The most common functioning pituitary adenoma is prolactinoma. Patients with medically refractory or residual/recurrent tumors that are not amenable to resection can be treated with stereotactic radiosurgery (SRS). The aim of this multicenter study was to evaluate the role of SRS for treating prolactinomas.
This retrospective study included prolactinomas treated with SRS between 1997 and 2016 at ten institutions. Patients’ clinical and treatment parameters were investigated. Patients were considered to be in endocrine remission when they had a normal level of prolactin (PRL) without requiring dopamine agonist medications. Endocrine control was defined as endocrine remission or a controlled PRL level ≤ 30 ng/ml with dopamine agonist therapy. Other outcomes were evaluated including new-onset hormone deficiency, tumor recurrence, and new neurological complications.
The study cohort comprised 289 patients. The endocrine remission rates were 28%, 41%, and 54% at 3, 5, and 8 years after SRS, respectively. Following SRS, 25% of patients (72/289) had new hormone deficiency. Sixty-three percent of the patients (127/201) with available data attained endocrine control. Three percent of patients (9/269) had a new visual complication after SRS. Five percent of the patients (13/285) were recorded as having tumor progression. A pretreatment PRL level ≤ 270 ng/ml was a predictor of endocrine remission (p = 0.005, adjusted HR 0.487). An increasing margin dose resulted in better endocrine control after SRS (p = 0.033, adjusted OR 1.087).
In patients with medically refractory prolactinomas or a residual/recurrent prolactinoma, SRS affords remarkable therapeutic effects in endocrine remission, endocrine control, and tumor control. New-onset hypopituitarism is the most common adverse event.
ABBREVIATIONSACTH = adrenocorticotropic hormone; EBRT = external beam radiotherapy; GH = growth hormone; IRRF = International Radiosurgery Research Foundation; PRL = prolactin; SRS = stereotactic radiosurgery; TSH = thyroxine-stimulating hormone.
Correspondence Jason Sheehan: University of Virginia, Charlottesville, VA. firstname.lastname@example.org.INCLUDE WHEN CITING Published online August 2, 2019; DOI: 10.3171/2019.4.JNS183443.Disclosures Dr. Grills owns stock in and serves on the board of directors for Greater Michigan Gamma Knife and receives funding from Elekta through her institution for non–study-related research. Dr. Lunsford owns stock in Elekta AB and is a consultant for Insightec, DSMB. Dr. Liscak is a consultant for Elekta AB. Dr. Zacharia is a consultant for Medtronic Inc. and serves on the Speakers Bureau for NICO Corp.
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