An early postoperative adjusted IGF-1 of less than or equal to 1.32 ULN optimally predicted 3-month remission, yielding a sensitivity of 60%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 61.3%.
The degree of decline in insulin-like growth factor 1 (IGF-1) within days of pituitary surgery strongly predicts biochemical remission of acromegaly at 3 months, according to a study published in World Neurosurgery.
In this retrospective cohort of 49 patients who underwent transsphenoidal resection for growth hormone-secreting pituitary adenomas between January 1999 and January 2025, greater perioperative IGF-1 reduction and lower early postoperative adjusted IGF-1 levels were independently associated with early remission. These results suggest that obtaining IGF-1 levels before discharge could improve postoperative prognostication and guide early clinical management.
The mean preoperative adjusted IGF-1 concentration was 2.50-fold the upper limit of normal (ULN) (SD, 0.88), decreasing to 1.43 (SD, 0.60) within a mean of 4.2 days after surgery (P <.001). Patients who achieved remission at 3 months (n=30, 61%) demonstrated significantly lower postoperative IGF-1 (1.13 ± 0.44 vs 1.89 ± 0.53 ULN, P <.01) and a greater mean perioperative reduction (49.7% ± 21.8% vs 22.2% ± 30.6%, P <.01) than those without remission.
Receiver operating characteristic analyses supported the predictive accuracy of early IGF-1 measures. The area under the curve was 0.841 for postoperative adjusted IGF-1 and 0.783 for perioperative IGF-1 reduction.
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An early postoperative adjusted IGF-1 of less than or equal to 1.32 ULN optimally predicted 3-month remission, yielding a sensitivity of 60%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 61.3%. A reduction of at least 44% perioperative IGF-1 produced sensitivity of 76.7%, specificity of 73.7%, positive predictive value of 82.1%, and negative predictive value of 66.7%.
Radiologic factors remained relevant but less predictive than biochemical indices. The absence of cavernous sinus invasion (P =.03) and achievement of gross total resection on 3-month MRI (P =.01) were significantly associated with remission. Tumor size was not associated with remission, suggesting that invasive behavior rather than absolute size drives surgical outcomes.
The accuracy of early postoperative IGF-1 was influenced by baseline disease activity. A preoperative adjusted IGF-1 2.46 ULN or less improved predictive reliability, with an area under the curve of 0.738. Conversely, when preoperative IGF-1 exceeded this threshold, postoperative IGF-1 was less reliable for predicting remission.
“[O]ur study demonstrates that measurements of adjusted IGF-1 levels and perioperative reduction of IGF-1 in the early postoperative period can accurately predict 3-month hormonal remission,” stated the authors. “Pending validation studies, these findings may be used to inform postoperative patient counselling prior to discharge, multidisciplinary discussions and follow-up protocols.”
Reference
Ovenden C, Mignone E, Chapman I, et al. Early postoperative decline in insulin-like growth factor 1 (IGF-1) predicts surgical remission of acromegaly. World Neurosurg. Published online November 3, 2025. doi:10.1016/j.wneu.2025.124611