Aggressive transsphenoidal resection of tumors invading the cavernous sinus in patients with acromegaly: predictive factors, strategies, and outcomes

Abstract

Object: Cavernous sinus (CS) invasion is the most important preoperative predictor of remission in the surgical treatment of growth hormone-producing pituitary adenomas. The purpose of this study was to evaluate the effectiveness of an aggressive technique for removal of tumors invading the CS in patients with acromegaly.

Methods: The authors retrospectively reviewed the cases of 150 consecutive patients with acromegaly who underwent primary transsphenoidal surgery in 2010 and 2011. The authors reviewed preoperative Knosp grade, intraoperative findings, histology of the medial wall of the CS, and surgical outcome according to the current consensus criteria for acromegaly.

Results: Cavernous sinus invasion was identified in 55 patients (36.7%): definite CS involvement by the tumor was observed under direct vision in 41 patients (74.5%), while invasion was histologically verified in 39 patients (70.9%). Invasion increased in frequency with the higher Knosp grade but was observed in 14.4% (13 of 90) of Grade 0 and 1 tumors. Overall, the remission rate fulfilling stringent criteria was 84.7% (127 of 150). Although CS invasion was significantly associated with an unfavorable outcome (p < 0.0001), remission was achieved in 69.1% (38 of 55) of patients with invasion. No major complications occurred in this series.

Conclusions: Cavernous sinus invasion is the most significant, independent predictor of unfavorable outcome. Confirmation of invasion requires direct observation within the CS regardless of the microscope or endoscope used. Particularly in cases in which only the medial wall is involved, histological verification is always necessary to detect the occult invasion. Direct removal of the invading tumor, by sharp excision of the medial wall of the CS, is effective and safe and increases the chance of remission.

Keywords: CS = cavernous sinus; GH = growth hormone; IGF-I = insulin-like growth factor–I; SD = standard deviation; TSS = transsphenoidal surgery; acromegaly; cavernous sinus invasion; occult invasion; oncology; pituitary adenoma; transsphenoidal surgery.