Predictors of endoscopic transsphenoidal surgery outcome in acromegaly: patient and tumor characteristics evaluated by magnetic resonance imaging

The availability of various first-line treatment modalities for acromegaly and evolving surgical techniques emphasize the need for accurately defined predictors of surgical outcome. We retrospectively analysed the outcome of 30 patients with acromegaly after initial endoscopic transsphenoidal surgery in two university hospitals from 2001 until 2009, and reviewed comparable literature investigating predictive tumor characteristics. Medical records were monitored for patient characteristics. Each pituitary magnetic resonance imaging (MRI) scan was revised independently by two neuroradiologists using a standardised analysis form to record distinctive predefined tumor characteristics. All characteristics were independently analysed as predictors for persistent disease, and a multivariable predictive model was created. Literature from 2000 onwards was searched for studies describing tumor characteristics predictive for surgical outcome. The cohort consisted of 27 macroadenomas with 90 % demonstrating signs of parasellar extension. The surgical cure rate overall was 30 %. Independently, next to male sex and increasing tumor size, infrasellar and parasellar extension based on MRI staging tended to increase the risk of persistent disease. In a multivariable analysis, sex and parasellar extension of the tumor were demonstrated to be the variables allowing for the best fitted predictive model for persistent disease. Earlier studies on preoperative tumor characteristics showed comparable results, although these were based on several different tumor classification systems. This retrospective study demonstrates that accurately defined tumor characteristics based on imaging, especially for cavernous sinus invasion, can be helpful in predicting surgical outcome. Comparative studies on different treatment modalities are essential for clinical practice within the scope of re-evaluation of the role of surgery in GH-secreting adenomas.