External validation of the PANOMEN-3 classification for predicting 1-year surgical remission in pituitary adenoma.

PURPOSE: The PANOMEN-3 classification was developed as a multidimensional framework to improve prognostic stratification in pituitary adenomas. While prior validation studies have primarily focused on long-term outcomes, its value in predicting early postoperative remission remains less well defined. We aimed to externally validate PANOMEN-3 for predicting 1-year remission in a single-center surgical cohort.

METHODS

This retrospective study included 77 consecutive patients who underwent transsphenoidal surgery for pituitary adenoma between June 2023 and January 2025. Tumors were classified according to the WHO 2022 criteria and graded using the PANOMEN-3 system. The primary endpoint was remission at 1 year, defined biochemically for functioning tumors and radiologically for non-functioning tumors. Logistic regression analysis was performed to evaluate the association between PANOMEN grade and remission. Receiver operating characteristic (ROC) analysis was used to assess discriminative performance.

RESULTS

At 1-year follow-up, remission was achieved in 52 of 77 patients (67.5%). Remission rates declined with increasing PANOMEN grade (Grade I: 87.5%; Grade II: 59.6%; Grade III: 50.0%; p = 0.0376). Logistic regression analysis demonstrated that PANOMEN-3 grade ≥ 2 was significantly associated with failure to achieve remission (OR 4.54, 95% CI 1.12–18.48, p = 0.034). ROC analysis demonstrated moderate discriminative performance (AUC 0.69). Ki-67 showed a moderate correlation with PANOMEN grade but was not significantly associated with remission.

CONCLUSIONS

The PANOMEN-3 classification is associated with early postoperative remission and may provide clinically relevant information for risk stratification in pituitary adenomas. These findings complement previous studies focused on long-term outcomes and suggest that PANOMEN-3 may also have value in the early postoperative setting. Further studies are needed to determine whether early remission predicts long-term disease control.