Résumé
Silent pituitary tumors (siPT), particularly silent corticotroph tumors (siACTH), are considered as more aggressive than other usual pituitary tumors. However, data about progression and/or recurrence after surgery are not consistent in the literature. Then, other tools are required in order to predict the clinical outcome after surgery. A French five-tiered histopronostic classification has been proposed to predict the risk of progression and/or recurrence of operated pituitary tumors. While this classification have been largely assessed on pituitary tumors, it has never been evaluated specifically on siPT. This current study aimed to evaluate the clinical outcome of siPT after surgery according this classification, in order to highlight predictive factors of recurrence/progression.Patients and methods: from patients operated for a PT from 2008 to 2022, we identified 39 siPT. For each were assessed the clinical, biological, radiological, histological and surgical characteristics. Pituitary tumors were considered silent if there were no clinical or biological signs of hypersecretion. The grading was established according to both invasion and proliferation. Progression-free survival (PFS) of the graded tumors was estimated using Kaplan-Meier method and log-rank test.Results: compared to patients with gonadotroph PT, patients with siPT were younger (51±16 vs. 60±11 yo, p=0.0006), had smaller tumor (23.4±7.7 vs. 27.8±8.1 mm, p=0.0023), had higher p53 expression (28.6% vs. 9.7%, p =0.0099) and invasion rate (33.3% vs. 12.6%, p=0.0088). Recurrence/progression occurred in 28.2% siPT (n=11, 8 siACTH and 3 siGH) compared to 18.2% gonadotroph tumors (p=0.1881). According to the grading system, invasive andproliferative (grade 2b) siPT had higher risk 8-fold-time progression/recurrence rather than non-invasive and non-proliferative (grade 1a) siPT (p=0.0125).Discussion: the five-tiered grading system may help to predict the clinical outcome of operated siPT and could advocate for a personalized therapeutic approach in invasive and proliferative siPT. However, this classification seems to be insufficient on its own to accurately predict the risk of relapse/progression in siACTH.