A Long-Term Study of the Treatment of Nelson's Syndrome With Gamma Knife Radiosurgery.

Abstract

Nelson's syndrome may be a devastating complication for patients with Cushing's disease who underwent a bilateral adrenalectomy. Previous studies have demonstrated that stereotactic radiosurgery (SRS) can be used to treat patients with Nelson's syndrome. To report a retrospective study of patients with Nelson's syndrome treated with Gamma Knife radiosurgery to evaluate the effect of SRS on endocrine remission and tumor control. Twenty-seven patients with Nelson's syndrome treated with Gamma Knife radiosurgery after bilateral adrenalectomy were included in this study. After radiosurgery, patients were followed with serial adrenocorticotropic hormone (ACTH) levels and MRI sequences to assess for endocrine remission and tumor control. Cox proportional hazards regression analysis was used to evaluate the relationship between the time to remission and potential prognostic factors. In 21 patients with elevated ACTH prior to SRS and endocrine follow-up data, 14 (67%) had decreased or stable ACTH levels, and 7 achieved a normal ACTH level at a median of 115 mo (range 7-272) post-SRS. Tumor volume was stable or reduced after SRS in 92.5% of patients (25/27) with radiological follow-up. Time to remission was not significantly associated with the ACTH prior to SRS (P= .252) or with the margin dose (P= .3). However, a shorter duration between the patient's immediate prior transsphenoidal resection and SRS was significantly associated with a shorter time to remission (P=.045). This retrospective analysis suggests that SRS is an effective means of achieving endocrine remission and tumor control in patients with Nelson's syndrome.