Assessing the clinical application of the PANOMEN 3 classification in a large cohort of pituitary tumors

Objective: Pituitary tumors are a heterogeneous group of neoplasms exhibiting a wide range of clinical and histological features. There are currently no comprehensive clinically validated prognostic tools to guide management of all tumor types before and after surgery. Recently, the PANOMEN 3 classification, incorporating risk factors for disease severity, was proposed as a potential grading system to assess prognosis. We aimed to evaluate the clinical utility and application of the new PANOMEN 3 classification. Design and Methods: We conducted a retrospective study of 215 cases of pituitary tumors surgically resected at Westmead Hospital between 2011 and 2018. All tumors were histologically examined according to the 2022 WHO Classification of pituitary tumors. Preoperative and postoperative PANOMEN 3 grades were assigned, and recurrence analyses performed. Results were compared to the French clinicopathological classification. Results: Compared to PANOMEN 3 grade 0, risk of recurrence was highest for grade 3 (HR 10.99; 95% CI 1.14-106.11, P = .038), followed by grade 2 (HR 7.85; 95% CI 1.06-58.31, P = .044), but not significantly different for grade 1. Proportions of tumors needing further intervention was greater with higher PANOMEN 3 grades; interventions occurred earlier in high grade tumors. The French classification remained a significant predictor of recurrence when adjusted for PANOMEN 3 (P < .001), but PANOMEN 3 was not a strong predictor when adjusted for French classification (P = .374). Conclusions: In the postoperative setting, PANOMEN 3 classification is useful in prediction of recurrence and need for further therapy. However, it was a weaker tool for predicting recurrence than the French classification.