Outcome of Transsphenoidal Surgery for Cushing Disease: A Single-Center Experience over 20 Years

BACKGROUND: This study investigated the outcome of transsphenoidal surgery (TSS) for Cushing disease (CD) and the influence of our surgical strategy on remission rates and postoperative pituitary function. PATIENTS AND METHODS: We retrospectively reviewed data from 71 patients with CD who underwent microscope navigation TSS (MN-TSS) in Saint-Luc Hospital between 1996 and 2017. True remission was defined as normal fasting cortisol level, normal 24-hour urinary free cortisol, or continued need for hydrocortisone replacement for 1 year after surgery. RESULTS: Overall remission rate after 1 or repeated MN-TSS was 83%. Highest remission rate was found in patients with macroadenomas (92%). Successful first MN-TSS was correlated with a high final remission rate (95%), whereas failed first MN-TSS was correlated with a low final remission rate (36%). Although day 1 cortisol levels were significantly lower in patients with long-term remission, high levels were still observed in a few patients, especially those who had had CD for many years. We found a low rate of postoperative pituitary long-term hypofunction (9.7%). CONCLUSIONS: MN-TSS is a safe and effective procedure to treat CD, allowing remission rates of 83%. One-year remission period after first surgery is correlated with a final remission rate of 95%. Although day 1 morning cortisol value is the most significant predictor for long-term remission, some patients with CD for many years may keep high postoperative cortisol levels and be in later remission, likely because of secondary adrenal hyperplasia. Our focused approach with microscope navigation resulted in low rates of postoperative pituitary hypofunction and kept a recurrence rate comparable to that in the literature.