Random Gh and Igf-I levels after transsphenoidal surgery for acromegaly: relation with long-term remission.

PURPOSE: To evaluate the role of IGF-I and random GH measurements 3 months after transsphenoidal surgery (TSS) in predicting long-term remission in acromegaly patients.
METHODS: Retrospective analysis of 54 acromegaly patients who underwent TSS with the same neurosurgery team. Random GH and IGF-I values evaluated 3 months after TSS were related to long-term outcomes. The initiation of adjuvant therapy at any time defined surgical failure.
RESULTS: At 3 months, 14 (25.9%) patients had controlled disease (CD; normal IGF-I and GH < 1.0 µg/L), 25 (46.3%) had uncontrolled disease (UD; high IGF-I and GH), and 15 (27.8%) had biochemical discrepancies (BD): 12 BDI (normal IGF-I + GH ≥ 1.0 μg/L) and 3 BDII (high IGF-I + GH < 1.0 μg/L). All patients of the CD group, 2 of the UD, 11 of the BDI, and 2 of the BDII, progressed with long-term remission and had IGF-I ≤ 1.25-fold the Upper Limit of Normal (ULN), in contrast with all cases of surgical failure where IGF-I was ≥1.3-fold ULN. Only one patient with normal IGF-I had recurrence, resulting in 100% sensitivity and 96% specificity of post-surgical IGF-I ≤ 1.25-fold ULN to predict long-term remission, observed in 54% of our cohort. Post-surgical random GH ≥ 1.7 µg/L was the best cutoff to identify surgical failure, but its accuracy to predict long-term outcomes was limited.
CONCLUSIONS: IGF-I levels ≤ 1.25-fold ULN 3 months after TSS was the best guide for long-term remission in acromegaly patients with both initial surgical failure and discrepant biochemical results.