Time to Biochemical Remission in Cushing's Disease: A Retrospective Review of “Intracapsular” versus “Extracapsular” Resections

Background: Because Cushing’s disease has up to five times higher mortality than the general population, establishing a surgical cure is critical to the overall health of these patients. Authorities have established that morning cortisol levels less than 2 microgram/dl suggest remission. However, despite gross total resection of the tumor, often times the “cortisol crash” does not occur on the morning of post-operative day one.

Objective: The authors reviewed all of their cases of Cushing’s disease to determine which tumors were resected with an intracapsular or extracapsular technique. They hypothesized that those patients who had an extracapsular resection “crashed” sooner during their hospital course than those who had an intracapsular extirpation.

Methods: The authors retrospectively reviewed patients who had pathology proven ACTH secreting adenomas that were resected by one surgeon at one center between 2011 and 2016. An institutional IRB has been obtained to review patients with pituitary tumors. A total of 45 surgical cases were reviewed; twenty-three were included in the study because these patients achieved a biochemical remission. There were thirteen patients in the extracapsular group and ten patients in the intracapsular group. The primary outcome was the time elapsed to physiologic hypocortisolism calculated from start of surgical resection. On average, patients who had an extracapsular dissection (Mean = 20.30 hour, SD = 10.12 hour; n = 13) crashed quicker than patients who did not (Mean = 41.25 hour, SD = 6.68 hour; n = 10), t(21) = 5.65, p < 0.001, d = 2.44. The Cohen’s D measure is a large effect. More patients will be added to this sample size after they present for surgery.

Conclusion: Regardless of the strategy use to remove the adenoma, the clinician can better counsel patients and their families regarding their post-operative course. Specifically, these results help neurosurgeons and endocrinologists anticipate the point in which a Cushing’s patient will need physiologic replacement with corticosteroids in the postoperative phase. In addition, this data suggests that the hospital stay for patients that have an extracapsular dissection can be shorter than their counterparts.