Progesterone Receptor Is Responsible for Benign Biology of Skull Base Meningioma

Objective: Many studies have been performed to evaluate the roles of estrogen receptor and progesterone receptor (PGR) in meningiomas, but their influence on tumor behavior remains unclear.

Methods: We retrospectively analyzed patients with meningioma who underwent surgical resection at our institute. Patients with data for immunohistochemical staining of estrogen receptor, PGR, and Ki-67 were included.

Results: The study included 161 patients comprising 61 skull base and 100 non-skull base meningiomas. Histologically, the number of patients with World Health Organization (WHO) grade I, II, and III disease were 132 (82.0%), 22 (14.7%), and 7 (4.4%), respectively. Tumor recurrence was observed in 21 (13.0%). Negative PGR, high Ki-67 index, incomplete resection, and WHO grade II or III were significantly correlated with tumor recurrence and shorter recurrence-free survival. Skull base meningiomas were difficult to remove entirely; 31 patients (50.8%) with skull base and 77 patients (77.0%) with non-skull base meningiomas had overall complete removal (P = 0.0006). Ki-67 indices, proportion of WHO grade II or III, and recurrence rate or recurrence-free survival did not differ between the tumor locations. The only difference was the proportion of patients with positive PGR, which was significantly higher for skull base meningiomas (61.5 ± 33.4% vs. 42.2 ± 35.7%, P = 0.0009).

Conclusions: Although skull base meningiomas are often incompletely resected, there were no differences in recurrence-free survival or recurrence rate between skull base and non-skull base meningiomas. As the Ki-67 index and WHO grade were not different between these locations, the high rate of positive PGR may be responsible for the benign biology of skull base meningiomas.