Introduction: Incompletely controlled acromegaly has a three-fold excess all-cause mortality, with stroke being the predominant cause of death. Debate exists about the relationship between fractionated radiation (FRT) and risk of stroke, with radiation damage to cerebral vasculature potentially being a cause. We present outcomes in patients treated by gamma knife STRS at the National Centre for Stereotactic Radiosurgery in Sheffield, with 30-year follow-up.
Methods: 118 patients with acromegaly underwent STRS in Sheffield between 1985 and 2015. Morbidity data were collected using notes review and direct patient or physician contact. NHS database and national death register provided date and cause of death where applicable.
Results: Of 118 patients, complete data is currently available on 64. Median follow up was 108 months (range 30363). There were 5 deaths: three due to lower respiratory tract infections; one due to Idiopathic pulmonary fibrosis; and one due to cardiac arrhythmia. Too few deaths precluded calculation of Standardised Mortality Ratios. Median age at death was 65 (3282) years and median follow-up post STRS at death was 103 (44168) months. Of those who had not undergone prior FRT 18/48 (37.5%) developed new hypopituitarism. There were four cases of ophthalmoplegia, two of whom received prior FRT and two STRS treatments. All four cases had tumours invading the cavernous sinus. One patient developed worsened visual acuity (STRS prior to MRI-targeted therapy in 1993). There was one case of an anterior circulation stroke (at age 80), at 7 years post STRS with no prior history of FRT. Three patients required further pituitary surgery; two further radiation treatment.
Conclusion: This is the longest reported follow-up of any cohort of patients with acromegaly treated by gamma knife, specifically assessing morbidity and mortality. Stroke risk appears to be low following STRS. Second radiation treatment and cavernous sinus invasion may increase risk of ophthalmoplegia.