Impact of tumor characteristics and pre- and postoperative hormone levels on hormonal remission following endoscopic transsphenoidal surgery in patients with acromegaly

OBJECTIVE Acromegaly is a disease of acral enlargement and elevated serum levels of insulin-like growth factor–1 (IGF-1) and growth hormone (GH), usually caused by a pituitary adenoma. A lack of consensus on factors that reliably predict outcomes in acromegalic patients following endoscopic endonasal transsphenoidal surgery (EETS) warrants additional investigation. METHODS The authors identified 52 patients with acromegaly who underwent an endoscopic endonasal approach (EEA) for resection of a GH-secreting pituitary adenoma. Preoperative and postoperative tumor and endocrinological characteristics such as tumor size, invasiveness, and GH/IGF-1 levels were evaluated as potential indicators of postoperative hormonal remission. Endocrinological remission was defined as postoperative IGF-1 levels at or below the age- and sex-normalized values. RESULTS The 52 patients had a mean age of 50.7 ± 13.4 years and a mean follow-up duration of 24.4 ± 19.1 months. Ten patients (19%) had microadenomas and 42 (81%) had macroadenomas. Five patients (9.6%) had giant adenomas. Forty-four tumors (85%) had extrasellar extension, with 40 (77%) exhibiting infrasellar invasion, 18 (35%) extending above the sella, and 7 (13%) invading the cavernous sinuses. Thirty-six patients (69%) underwent gross-total resection (GTR; mean maximal tumor diameter 1.47 cm), and 16 (31%) underwent subtotal resection (STR; mean maximal tumor diameter 2.74 cm). Invasive tumors were significantly larger, and Knosp scores were negatively correlated with GTR. Thirty-eight patients (73%) achieved hormonal remission after EEA resection alone, which increased to 87% with adjunctive medical therapy. Ninety percent of patients with microadenomas and 86% of patients with macroadenomas achieved hormonal remission. Preoperative IGF-1 and postoperative day 1 (POD1) GH levels were inversely correlated with hormonal remission. Postoperative CSF leakage occurred in 2 patients (4%), and none experienced vision loss, death, or injury to internal carotid arteries or cranial nerves. CONCLUSIONS Endoscopic transsphenoidal resection of GH-secreting pituitary adenomas is a safe and highly effective treatment for achieving hormonal remission and tumor control in up to 87% of patients with acromegaly when combined with postoperative medical therapy. Patients with lower preoperative IGF-1 and POD1 GH levels, with less invasive pituitary adenomas, and who undergo GTR are more likely to achieve postoperative biochemical remission.