Long-term outcomes of modern radiation therapy for pituitary adenoma - different techniques: single institute experience.

Background: Pituitary adenomas are relatively common benign intracranial tumors that may cause significant hormonal imbalances and visual impairments. Radiotherapy (RT) remains an important treatment option, particularly for patients with residual tumor after surgery, recurrent disease, or ongoing hormonal hypersecretion. This study summarizes long-term clinical outcomes and radiation-associated toxicities in patients with pituitary adenomas treated with contemporary radiotherapy techniques at a single institution.

Methods: A retrospective analysis was conducted on 122 patients treated with RT for pituitary adenomas at the tertiary Hospital in Germany between 1992 and 2023. Patient data were assessed for tumor characteristics, treatment modalities, and outcomes. Overall survival (OS), and local control (LC) were evaluated using Kaplan-Meier analysis. Statistical comparisons between subgroups were performed with the log-rank test. Treatment-related toxicities were graded according to the Common Terminology Criteria for Adverse Events (CTCAE), version 5.0.

Results: Median follow-up was 107 months from initial diagnosis and 63 months post-RT. Most patients (96%) received fractionated stereotactic radiotherapy (FSRT), and 4% underwent single-session radiosurgery. RT achieved LC rates of 95% and 75% at 5 and 20 years, respectively. Proton therapy significantly improved LC and overall survival (OS) compared to photon-based treatments (p < 0.01). Hypopituitarism was the most common long-term toxicity, occurring in 40% of patients, while visual impairments were rare (< 3%). Tumor recurrence occurred in 9% of patients, primarily in those treated with delayed RT after incomplete resection.

Conclusion: Modern RT techniques, particularly proton therapy, provide durable tumor control and manageable toxicity profiles for pituitary adenomas. Optimized timing and precision in RT delivery are critical to enhancing outcomes and minimizing complications. Long-term follow-up remains essential to monitor disease progression and late toxicities.