Predictors of biochemical remission and recurrence after surgical and radiation treatments of cushing disease: A systematic review and meta-analysis

Objective: We conducted a systematic review and meta-analysis to synthesize the evidence about predictors that may affect biochemical remission and recurrence after transsphenoidal surgery (TSS), radiosurgery (RS), and radiotherapy (RT) in Cushing disease. Methods: We searched multiple databases through December 2014 including original controlled and uncontrolled studies that enrolled patients with Cushing disease who received TSS (first-line), RS, or RT. We extracted data independently, in duplicates. Outcomes of interest were biochemical remission and recurrence. A meta-analysis was conducted using the random-effects model to estimate event rates with 95% confidence intervals (CIs). Results: First-line TSS was associated with high remission (76% [95% CI, 72 to 79%]) and low recurrence rates (10% [95% CI, 6 to 16%]). Remission after TSS was higher in patients with microadenomas or positive-adrenocorticotropic hormone tumor histology. RT was associated with a high remission rate (RS, 68% [95% CI, 61 to 77%]; RT, 66% [95% CI, 58 to 75%]) but also with a high recurrence rate (RS, 32% [95% CI, 16 to 60%]; RT, 26% [95% CI, 14 to 48%]). Remission after RS was higher at short-term follow-up (≤2 years) and with high-dose radiation, while recurrence was higher in women and with lower-dose radiation. Remission was after RT in adults who received TSS prior to RT, and with lower radiation doses. There was heterogeneity (nonstandardization) in the criteria and cutoff points used to define biochemical remission and recurrence. Conclusion: First-line TSS is associated with high remission and low recurrence, while RS and RT are associated with reasonable remission rates but important recurrence rates. The current evidence warrants low confidence due to the noncomparative nature of the studies, high heterogeneity, and imprecision.