Transsphenoidal Surgery for Acromegaly: Methods of Surgical Resection, Remission Using Modern Criteria, and Predictors of Outcome

Introduction: Whether endoscopic or microscopic surgical approaches are superior for patients with acromegaly remains unclear. Recent consensus requires use of more stringent endocrine remission criteria than were previously used. We reviewed our experience with endoscopic transsphenoidal surgery (ETSS) and microsurgical transsphenoidal surgery (MTS) to assess outcomes and predictors of remission according to the 2010 consensus criteria.

Methods: The prospectively recorded outcomes of 110 acromegalic patients undergoing surgical therapy were reviewed. Remission was defined as a normal IGF-I and either a suppressed growth hormone (GH) less than 0.4 ng/mL during an oral glucose tolerance test or a random GH less than 1.0 ng/mL.

Results: Remission was achieved in 19 of 24 microadenomas (79%) and 53 of 86 macroadenomas (62%). Baseline characteristics, remission rates, and complications were not significantly different between patients undergoing ETSS and MTS. A postoperative GH level of less than 1.0 ng/mL provided the best predictor of remission (OR = 45.6, 95% CI 9.9–210.9, P < 0.001). Preoperative variables predictive of remission in univariate analysis included age (P = 0.004), preoperative GH level (P = 0.006), preoperative IGF-1 (P = 0.009), tumor size (P < 0.001), and Knosp score (P < 0.001). Preoperative variables predictive in multivariate analysis included GH > 25 ng/mL (R = 4.9, 95% CI 1.5–16.5, P = 0.01) and Knosp score of 3 or 4 (OR = 25.0, 95% CI 5.0–125.8, P < 0.001).

Conclusions: ETSS and MTS provide high rates of remission according to the updated guidelines for surgery for acromegaly. Patients with high preoperative GH levels and Knosp scores are less likely to achieve remission, and the 2010 census guidelines provide excellent postoperative prediction of remission.