Early Postoperative Decline in Insulin-Like Growth Factor 1 (IGF-1) Predicts Surgical Remission of Acromegaly

To determine the utility of perioperative decline in insulin-like growth factor 1 (IGF-1) in predicting 3-month remission in patients undergoing surgery for growth hormone-secreting pituitary adenomas.

This was a retrospective, single-center cohort study of patients with surgically managed growth hormone-secreting pituitary adenomas from January 1, 1999, to January 1, 2025. We compared the utility of early postoperative adjusted IGF-1 (adjusted to upper limit of normal) and early postoperative adjusted IGF-1 reduction compared with preoperative levels to predict hormonal remission (normal IGF-1) at 3 months' postoperatively. Other clinical/radiologic factors associated with 3-month remission also were examined.

We identified 49 patients with mean age 47.6 ± 12.5 years (standard deviation 12.5 years); 29 were female (59%). Mean values were 2.50-fold the upper limit of normal (standard deviation 0.88) for preoperative adjusted IGF-1 and 1.43 ± 0.6 the upper limit of normal for early postoperative adjusted IGF-1 (P < 0.001) measured at a mean of 4 days postoperatively. Early postoperative adjusted IGF-1 was lower in those who achieved 3-month remission versus those who did not (1.13 ± 0.44 vs. 1.89 ± 0.53, P < 0.01), and perioperative IGF-1 reduction was considerably greater (49.7 ± 21.8 vs. 22.2 ± 30.6, P < 0.01). Receiver operating curve of early postoperative adjusted IGF-1 in predicting 3-month remission demonstrated an area under the curve of 0.841. Receiver operating curve of perioperative IGF-1 reduction demonstrated an area under the curve of 0.783.

The degree of IGF-1 decline within days of pituitary surgery predicts 3-month acromegaly remission. Our findings argue for IGF-1 measurement before discharge to inform patient counseling during the surgical admission and guide intensity of early follow-up.