Our literature review suggests that RON occurs in 1.36% of patients with GH-secreting pituitary adenoma, treated with external beam photon radiation therapy. Assuming that in as much as 50% of reported cases, no risk factors related to radiation therapy were present, would suggest that other risk factors, including vascular compromise and GH-secreting pituitary adenoma itself, contribute to RON occurrence. RON may occur after a considerable latency period. A female preponderance for developing RON is suggested.
The current dose-fractionation policy in our department is 45 Gy in 1.8 Gy fractions for all pituitary adenomas if radiation therapy is indicated. To our opinion there is no benefit in applying a higher total dose in pituitary adenoma radiation treatment, because a dose-volume effect above 45 Gy is absent60. Taken into consideration that in 50% of RON cases radiation treatment characteristics are likely to contribute to the development of this complication, our treatment scheme could further decrease RON
development.