Pitfalls in early biochemical evaluation after transsphenoidal surgery in patients with acromegaly

Although the current remission criteria for acromegaly are clear and concise, some pitfalls have been reported in early endocrinological evaluation after surgery. To evaluate the long-term (> 4 year) outcome and to detect the pitfalls in early evaluation, we retrospectively reviewed 128 patients with acromegaly who underwent primary transsphenoidal surgery during 2011 and 2012. These included 66 men and 62 women, aged from 7 to 76 (mean 46) years old. 49 patients (38.3%) were preoperatively treated with somatostatin analog (SSA). Follow-up period ranged from 52 to 75 (63) months. Long-term remission using the current consensus criteria was achieved in 107 patients (83.6%), 105 of which patient had achieved remission in early evaluation. In 5 patients with preoperative SSA treatment, IGF-1 levels re-elevated more than one year after surgery. Five female patients without pretreatment with SSA showed delayed normalization of IGF-1 between 13 to 27 months postoperatively, two of which patients satisfied the remission criteria. In conclusion, the long-term results can be reliably predicted by the remission criteria early after surgery in most patients with acromegaly. For the accurate evaluation within a year after surgery, however, influence of preoperative treatment with SSA, delayed normalization of IGF-1, and poor GH suppression due to low insulin resistance must be considered, particularly in women.