Classifying Pituitary Adenoma Invasiveness Based on Radiological, Surgical and Histological Features: A Retrospective Assessment of 903 Cases

Invasiveness is a major predictor of surgical outcome and long-term prognosis in patients with pituitary adenomas (PAs). We assessed PA invasiveness via radiological, surgical and histological perspectives to establish a classification scheme for predicting invasive behavior and poor prognosis. We retrospectively analyzed 903 patients who underwent transnasal-transsphenoidal surgery between January 2013 and December 2019. Radiological (hazard ratio (HR) 5.11, 95% confidence interval (CI): 3.98-6.57, p < 0.001) and surgical (HR 6.40, 95% CI: 5.09-8.06, p < 0.001) invasiveness better predicted gross-total resection (GTR) and recurrence/progression-free survival (RPFS) rates than did histological invasiveness (HR 1.44, 95% CI: 1.14-1.81, p = 0.003). Knosp grades 2 (HR 4.63, 95% CI: 2.13-10.06, p < 0.001) and 3 (HR 2.23, 95% CI: 1.39-3.59, p = 0.011) with surgical invasiveness were better predictors of prognosis than corresponding Knosp grades without surgical invasiveness. Classifications 1 and 2 were established based on radiological, surgical and histological invasiveness, and Knosp classification and surgical invasiveness, respectively. Classification 2 predicted RPFS better than Knosp classification and Classification 1. Overall, radiological and surgical invasiveness were clinically valuable as prognostic predictors. The convenience and good accuracy of Invasiveness in Classification 2 is useful for identifying invasive PAs and facilitating the development of treatment plans.

Automated summary

Invasiveness is an important predictor of surgical outcome and long-term prognosis in patients with pituitary adenomas (PAs). This study assessed PA invasiveness through radiological, surgical, and histological perspectives and established a classification scheme to predict invasive behavior and poor prognosis. The study found that radiological and surgical invasiveness were better predictors of complete resection and recurrence/progression-free survival rates than histological invasiveness. Knosp grades with surgical invasiveness were also better predictors of prognosis compared to Knosp grades without surgical invasiveness. The classification schemes developed based on invasiveness and Knosp classification were found to be clinically valuable in predicting prognosis.