Introduction: The criteria for biochemical remission in acromegaly patients have changed numerous
times over the past decade. The latest criteria set in 2022 by the Acromegaly Consensus
Conference defined remission as an IGF-1 level less than 1.3 times the age normalized
upper limit of normal. Since the release of these guidelines, no large-scale retrospective
studies have examined the outcomes, lesion characteristics, and factors predictive
of biochemical remission in patients with the latest guidelines.
Objectives: This article aims to characterize the clinical outcomes and factors predictive of
biochemical remission in patients with symptomatic acromegaly receiving transsphenoidal
surgery (TSS), as defined by the most recent guidelines.
Methods: In this single-institution, retrospective study, a large cohort of 158 patients diagnosed
with operative acromegaly was examined. Thirty-eight patients were excluded as IGF-1
testing was performed less than 12 weeks postoperatively. The lesion, surgical, clinical,
and endocrinological characteristics at baseline and postoperatively were tracked
for the remaining 120 patients. Hormone values were determined at baseline and up
to 3 years postoperatively. Pituitary adenoma size, location, and dimensions were
determined using preoperative magnetic resonance imaging (MRI) and computerized tomography
(CT) imaging. T-tests and chi-square tests were not performed due to the high type-1 error rate.
A multivariate logistic regression model was created to identify the factors predictive
of biochemical remission failure.
Results: A total of 120 patients receiving TSS for pituitary adenomas from 2008 to 2024 were
included, 91 of which achieved biochemical remission (75.8%). The most common preoperative
symptoms were headache (46.7 vs. 27.6%, in patients who achieved vs. failed to achieve
biochemical remission), visual loss (20.9 vs. 13.8%, respectively), and acromegalic
bone changes (69.2 vs. 69%, respectively). Moreover, preoperative obesity occurred
at a higher rate in those who achieved remission (23 vs. 0%). Patients who failed
remission tended to have higher raw IGF-1 levels preoperatively compared to those
who attained remission (732 ± 313 vs. 278 ± 313, respectively), and experienced higher
rates of GH hypersecretion (93.1 vs. 78.4%). Those who failed remission also tended
to have higher GH levels and IGF-1 levels postoperatively, and experienced a lower
percentage reduction in raw IGF-1 levels.
The majority of tumors were intrasellar (88 vs. 96.4% in those who attained vs. failed
remission), macroadenomas (75.8 vs. 72.4%). Nearly all patients (98.3%) received endoscopic
surgery. Postoperatively, the rates of complications such as SIADH (7.7 vs. 6.9% in
patients with vs. without remission) and transient diabetes insipidus (9.9 vs. 6.9%)
were largely similar.
Multiple logistic regression demonstrated that surgical and lesion characteristics
such as gross total resection, size, and suprasellar location were not significantly
associated with an increased risk of remission failure. Among endocrinologic characteristics,
the magnitude of preoperative IGF-1 and the percentage change in IGF-1 were associated
with an increased risk of remission failure (odds ratios of 1.001 and 1.021, respectively).
Conclusion: Overall, tumors which failed to achieve biochemical remission displayed distinctive
preoperative endocrinological characteristics; however, tumor size and location were
not necessarily predictive of worse postoperative outcomes.
