Introduction: Usually benigns, pituitary tumors (PT) can be invasive and aggressive with propensity to progress and/or recur. Trouillas’s clinicopathological classification attempts to predict the evolutionary risk of a PT. We assessed the prognostic value of this classification in an independent patient cohort and analyzed its impact over the treatment strategies.
Material and methods: 607 operated patients between 2008-2018 for a PT were included. Grading was established based on invasion, proliferative activity (Ki-67, mitotic index) and p53 positivity. The therapeutic management following surgery was analyzed. Progression-free survival (PFS) of the graded tumors was estimated (Kaplan-Meier method and log-rank test) and a multivariate analysis was performed (Cox regression model).
Results: Grading identified non-invasive PT without (grade 1a: 303 cases) or with proliferative activity (1b: 53 cases) and invasive PT without (2a: 202 cases) or with proliferative activity (2b: 49 cases). The mean follow up was 47 ± 30 months (median: 38 months). Progression/recurrence occurred in 127 cases. Grades were significant and independent predictors of PFS (p<0.001) with a 4.8 fold-higher risk of progression/recurrence in grade 2b as compared to grade 1a. As second-line therapy, gamma-knife or conventional radiotherapy controlled tumor growth in 91.6 and 100% of cases, respectively, irrespective of the grade. Proliferative tumors exposed the patient to a 9.5-fold higher risk of having ≥ 3 adjuvant therapeutic lines as compared to non-proliferative tumors.
Discussion: Grading of a PT according to Trouillas’s classification predicts its risk of progression and should advocate for a personalized therapeutic approach in invasive and proliferative tumors.