Treatment Outcome of Intensity-modulated Radiotherapy for 15 Patients with Giant Pituitary Adenoma

Objective The aim of this study is to summarize the clinical experience of intensity-modulated radiotherapy (IMRT) for patients with pituitary giant adenoma, and to provide evidence for clinical treatment. Methods The data of patients with pituitary giant adenoma who received 6MV-X IMRT with linear accelerator (prescription dose of 56~60 Gy/28~30 fractions, 5 fractions per week) in the Radiotherapy Department of Peking Union Medical College Hospital from October 2012 to October 2018 were reviewed. Treatment outcomes were evaluated by the control rate of tumor growth, remission rate of endocrine hormone, and radiation-related complications. Results A total of 15 patients were included in this study. There were 8 males with a median age of 32 years. The control rate of tumor growth was 93.3% (partial response in 11 cases, stable in 3 cases, and development of pituitary carcinoma in 1 case). Among the 7 patients with functional pituitary giant adenoma, 1 patient achieved complete remission of the level of endocrine hormone and 2 patients achieved partial remission. 4 of 15 patients treated with radiotherapy plus temozolomide achieved partial remission (median remission time was 5 months), and the remission rate and remission time were better than those who did not receive temozolomide. During the follow-up period after radiotherapy, four patients were found having newly pituitary dysfunction. There were no new or aggravating visional impairment and visual field defects. Conclusion Intensity-modulated radiotherapy is an effective treatment for pituitary giant adenoma, which can reduce the tumor faster combined with temozolomide.