A Prospective, Randomized, Multicenter Clinical Study Comparing Adjuvant Radiotherapy Versus Observation in High-risk Localized Adrenocortical Carcinoma After Surgery.

"1. Technique:Linear accelerator with volumetric modulated arc therapy for irradiation.~2. Target Volume Delineation (Two-phase irradiation):~Clinical Target Volume 1 (CTV1):Encompasses tumor bed (preoperative MRI/CT-defined ACC extent) + regional lymphatics (ipsilateral para-aortic nodes).~Clinical Target Volume 2 (CTV2):Tumor bed only (preoperative MRI/CT-defined ACC extent).~Planning Target Volume (PTV):PTV1: CTV1 + 0.6 cm margin.PTV2: CTV2 + 0.6 cm margin.~4.Organs at Risk (OARs):Stomach, liver, bilateral kidneys, pancreas, spinal cord, and bowel/colon within radiation fields.~5.Prescription Dose: Phase 1: PTV1 → 45 Gy in 25 fractions (1.8 Gy/fraction), 5 fractions/week. Phase 2: PTV2 → 10 Gy in 5 fractions (2.0 Gy/fraction), 5 fractions/week."