Transsphenoidal surgery for acromegaly: Endocrinological follow-up of 98 patients

OBJECTIVE: Transsphenoidal surgery is the preferred treatment modality for growth hormone (CH)-secreting pituitary adenomas. In many series, the repor ted postoperative remission is based mainly on achievement of CH levels les s than 2 ng/ml. Strict criteria for insulin-like growth factor I normalizat ion and even lower CH levels (<1 ng/ml) are now suggested to define cure of acromegaly, but the evidence does not yet support such low CH levels in ep idemiological follow-up. We analyzed our postoperative results in a large c ohort of patients with acromegaly. METHODS: Ninety-eight patients harboring GH-secreting adenomas (46 microade nomas and 52 macroadenomas) underwent transsphenoidal surgery between 1990 and 1999. Ninety-one patients were operated for the first time, and 12 pati ents underwent reoperations because of previous surgical failure (7 had und ergone surgery elsewhere previously). Biochemical remission was defined as a repeated fasting or glucose-suppressed CH level of 2 ng/ml or less, and a normal insulin-like growth factor I level. RESULTS: Remission was achieved in 74% of all patients after one operation, including 84% of patients with microadenomas and 64% of patients with macr oadenomas. Seventy-three percent of patients with macroadenomas 11 to 20 mm in size achieved remission, as compared with a 20% remission rate for pati ents with adenomas larger than 20 mm. Patients with preoperative random CH levels lower than 50 ng/ml had a better outcome (85 % remission), whereas C H greater than 50 ng/ml was associated with remission in 30% of the patient s. Only one of the patients (8%) with postoperative active disease who unde rwent a second operation achieved remission. Recurrence was rare (one patie nt), and all failed surgical attempts could be detected during the immediat e postoperative evaluation. CONCLUSION: On the basis of strict postoperative GH and insulin-like growth factor I criteria to define remission, our series demonstrates the efficac y of transsphenoidal surgery for acromegalic patients with microadenomas an d noninvasive macroadenomas. However, patients with large adenomas (> 20 mm ) and preoperative CH greater than 50 ng/ml have a poor prognosis and requi re adjunctive medical or radiation therapy to control GH hypersecretion.