Outcome of transsphenoidal surgery for Cushing's disease: a high remission rate in ACTH-secreting macroadenomas.

OBJECTIVE: Although numerous studies have shown that transsphenoidal surgery is the best initial treatment for Cushing disease offering 59-95% of success, fewer information is available on the long-term outcome in the subgroup of patients harboring ACTH-secreting macroadenomas. The aims of this study were to analyze our 10-year experience with transsphenoidal surgery in Cushing's disease and to examine whether remission rates were different between micro- and macroadenomas.

PATIENTS AND METHODS: Forty consecutive patients with proven Cushing's disease (28 microadenomas, 12 macroadenomas [diameter: 10-25 mm], 3 patients with no visible adenoma at MRI) underwent transsphenoidal surgery (TSS) assisted by neuronavigation in our center between 1996 and 2007. The diagnosis was made using standard endocrinological criteria including bilateral inferior petrosal sinus sampling (BIPSS) with CRH stimulation in all patients with discordant or equivocal biochemical and radiological testing. Morning serum cortisol was measured during the first week postoperatively, and a complete endocrine evaluation was made in all patients at 6-8 weeks. Remission at follow-up was defined as a normal postoperative 24-h urinary free cortisol (UFC) or continued need for glucocorticoid hormone replacement after TSS.

RESULTS: Overall, 32/40 patients (80%) were in remission after one or more TSS. Interestingly, a very good remission rate (92%) was observed in the subset of macroadenomas, similar to that found in the group of microadenomas (84%, NS), while no post-surgical remission was observed in the 3 patients with no visible adenoma at MRI (p<0.01). Of the 8 patients not in remission after repeated TSS surgery, 3 underwent radiation therapy and three had bilateral adrenalectomy, allowing remission of their hypercortisolism. There was minor morbidity and no death.

CONCLUSION: While our overall results are in accordance with other published series, we show here that ACTH-secreting pituitary macroadenomas are usually not associated with a bad outcome, in contrast with patients with no visible adenoma at preoperative MRI.