The Clinical Usefulness of the Trouillas Classification: 2b or not 2b

Pituitary adenomas, also known as pituitary neuroendocrine tumours (PitNETs), are mostly benign but can occasionally behave aggressively, leading to multiple recurrences or progression despite optimal treatment. The “Trouillas classification” proposed in 2013 integrates tumour invasion and proliferation markers to predict recurrence and prognosis. Grade 2b tumours (invasive and proliferative) are associated with a higher risk of aggressive behaviour. A modified version of this classification, introducing grade 2b* (with Ki-67 ≥ 10%), may further improve prediction of malignant potential.
This Endo-ERN EuRREB study — The Clinical Usefulness of the Trouillas Classification: 2b or not 2b — aims to validate this system using data from the European Core Registry and the Pituitary Tumour Module. Over 3,000 patients with surgically treated pituitary adenomas will be included. The study will assess how well the Trouillas classification predicts tumour recurrence, aggressiveness, and carcinoma development. The ultimate goal is to refine prognostic tools to guide early identification and personalized management of high-risk patients across European Reference Centres.

Objective

The primary aim is to evaluate the incidence of APT/PC among the different grades of the Trouillas’ classification in patients with all types of pituitary adenomas operated on at Endo-ERN Reference Centers.

The secondary aim (for a second paper) is to assess the unadjusted and adjusted predictive values of the individual risk factors included in the Trouillas’ classification on tumour recurrence and tumour behaviour with all types of pituitary adenoma operated on at Endo-ERN Reference Centers.

Hypothesis

We hypothesize that the Grade 2b is associated with higher incidence of aggressive pituitary tumours and carcinomas.

Data collection  

The aim is to collect data on 3000 patients with pituitary adenoma.

Longitudinal data will be collected at the following disease time points: at diagnosis, 2 years after diagnosis, 4 years after diagnosis, 5 years after diagnosis, 10 years after diagnosis, at the time of an intervention and 6 months after an intervention, and (in case of progression not followed by any intervention) at the moment of progression.

During FU, study members are asked to register if an event has occurred, and if so, to specify the exact date of the event.
A final assessment of the patient’s status will be made on 15 December 2025 of those patients who are still in FU.

Members of this Study Group