Utility of the Immediate Postoperative Cortisol Concentrations in Patients With Cushing's Disease

In Brief BACKGROUND Several investigators have recommended serial measurements of serum cortisol in the days following pituitary surgery to identify patients at risk of recurrence. OBJECTIVE We systematically reviewed the literature on this topic and analyzed the usefulness of this test in our own patient population. METHODS We identified studies publishing data regarding recurrence rates after transsphenoidal surgery for Cushing's disease, focusing on studies with data regarding patients with early postoperative cortisol levels. We determined a cumulative relative risk of having a subnormal vs normal cortisol level postoperatively using a fixed-effects meta-analysis model. Additionally, we analyzed our own patients with Cushing's disease undergoing transsphenoidal surgery and performed Kaplan-Meier analysis of recurrence-free survival for patients with undetectable, subnormal but detectable, and normal immediate 8 AM serum cortisol levels. RESULTS Fourteen studies met inclusion criteria. The length of follow-up varied between 32 and 115 months. The cumulative rate of recurrence in the group of patients with subnormal cortisol levels was 9% (95% confidence interval: 6%–12%). The cumulative rate of recurrence in the group with normal cortisol levels was 24% (95% confidence interval: 17%–31%). We analyzed 73 of our own patients and found similar recurrence rates in patients with subnormal vs normal early postoperative cortisol levels (4% vs 22%, χ2 test, P < .05). CONCLUSION Although a subnormal early postoperative cortisol level is predictive of improved outcome after transsphenoidal surgery for Cushing's disease, it is not analogous with cure, nor is a normal level completely predictive of future failure. BACKGROUND: Serial measurements of serum cortisol in the days following pituitary surgery are recommended to identify patients at risk of recurrence. OBJECTIVE: We systematically reviewed the literature and analyzed the usefulness of this measurement in our patient population. METHODS: We identified studies regarding recurrence rates after transsphenoidal surgery for Cushing's disease, focusing on studies with data of early postoperative cortisol levels. We determined a cumulative relative risk of a subnormal versus normal cortisol level postoperatively using a fixed-effects meta-analysis model. Additionally, we analyzed our patients with Cushing's disease undergoing transsphenoidal surgery and performed Kaplan-Meier analysis of recurrence-free survival for patients with undetectable, subnormal but detectable, and normal immediate 8 AM serum cortisol levels. RESULTS: Fourteen studies met inclusion criteria. The length of follow-up varied between 32 and 115 months. The cumulative rate of recurrence in the group of patients with subnormal cortisol levels was 9% (95% confidence interval: 6%–12%). The cumulative rate of recurrence in the group with normal cortisol levels was 24% (95% confidence interval: 17%–31%). We analyzed 73 of our patients and found similar recurrence rates in patients with subnormal versus normal early postoperative cortisol levels (4% vs 22%, χ2 test, P < .05). CONCLUSION: Although a subnormal early postoperative cortisol level is predictive of improved outcome after transsphenoidal surgery for Cushing's disease, it is not analogous with cure, nor is a normal level predictive of failure.