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

Inclusion Criteria: * age ≥ 18 years and ≤ 75 years. * ECOG performance status score ≤ 1, with an expected survival period ≥ 6 months. * Completion of radical resection for adrenocortical carcinoma (ACC) with curative intent. * Postoperative pathological diagnosis of adrenocortical carcinoma. * Pathological stage is localized ACC: ENSAT stage 1-3; where ENSAT stage 3 is defined as any T stage (T1-4) with regional lymph node positivity, or tumor invasion into surrounding tissues/organs or the renal vein/inferior vena cava, but without distant metastasis. * High-risk factors: Ki-67 index \>10%, ENSAT stage 3, positive resection margin, high pathological grade; the presence of any one of these factors qualifies. * Postoperative imaging review prior to radiotherapy shows no evidence of residual or metastatic disease. Exclusion Criteria: * ENSAT Stage 4 adrenocortical carcinoma. * Performance status: Karnofsky Performance Status (KPS) score ≤ 70 or Zubrod score \> 2. * Prior radiotherapy to the abdomen or pelvis. * Insufficient function of major organs (heart, lung, liver, kidney, bone marrow hematopoiesis) precluding tolerance to radiotherapy. * Pregnant or lactating women, and subjects of childbearing potential unwilling to use contraception. * Patients with psychiatric disorders, history of alcoholism or substance abuse, or those unable to provide informed consent. * Other conditions deemed by the investigator to make the subject unsuitable for participation in this trial, i…