Study Background: Both proton therapy and intensity-modulated radiation therapy (IMRT) utilize high-energy particles and X-rays to eliminate tumors. While both therapies exhibit similar tumor control efficacy, they differ in their impact on normal tissues, leading to variations in adverse effects. Post-surgical radiation therapy is crucial for preventing recurrence and improving survival rates; therefore, minimizing adverse effects significantly impacts patients' quality of life. ## Trial Design and Key Evaluation Metrics: This early-phase I clinical trial, led by Mayo Clinic, compares acute gastrointestinal toxicity in patients receiving proton therapy and IMRT. The primary evaluation involves quality-of-life questionnaires and adverse event reports at the end of treatment, aiming to capture both objective clinical data and patient-reported outcomes. ## Industry and Investment Perspective: If proton therapy demonstrates a significant reduction in gastrointestinal toxicity, hospitals can achieve economic benefits through improved patient satisfaction and reduced readmission rates relative to treatment costs. Conversely, if the difference is minimal, the continued use of existing IMRT is likely, necessitating a cautious approach to investments in related equipment.