Hypofractionated Radiotherapy After Complete Resection for Stage II/III Thymic Epithelial Tumors

Inclusion criteria

• Patients who voluntarily agree to participate in this study, sign the informed consent form, demonstrate good compliance, and are willing to comply with scheduled follow-up visits.
• Age 18-75 years, male or female.
• Histopathologically confirmed thymoma or thymic carcinoma after R0 complete resection. Eligible disease stages according to the Masaoka-Koga staging system include Stage II-III thymic carcinoma, Stage IIA Type B3 thymoma, Stage IIB Type B2/B3 thymoma, and Stage III thymoma.
• Eastern Cooperative Oncology Group performance status of 0-1.
• Life expectancy of at least 3 months.
• Adequate major organ function to meet the requirements of study treatment, including bone marrow, hepatic, renal, and coagulation function according to protocol-specified criteria.
• Patients with reproductive potential must agree to use medically acceptable contraception during study treatment and for 6 months after completion of study treatment. Female patients of childbearing potential must have a negative pregnancy test before enrollment and must not be breastfeeding.

Exclusion criteria

• Patients who do not meet the protocol-specified requirements for pathological type, disease stage, or histological subtype.
• Patients who have not undergone surgical treatment, or who underwent R1 or R2 resection, or who have definite gross residual disease.
• Prior thoracic radiotherapy.
• Major surgery other than the tumor resection procedure or severe trauma within 4 weeks before the first radiotherapy treatment.
• Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage.
• Prior or ongoing non-protocol-specified antitumor therapy, including immunotherapy, targeted therapy, radiotherapy, or other investigational treatment.
• Active autoimmune disease or a history of severe autoimmune disease that, in the investigator's judgment, makes the patient unsuitable for radiotherapy.
• History of immunodeficiency, including HIV positivity, history of organ transplantation, or history of allogeneic bone marrow transplantation.
• Uncontrolled severe cardiovascular disease, such as New York Heart Association Class II or higher heart failure, unstable angina, myocardial infarction within 1 year, or severe arrhythmia requiring clinical intervention.
• Severe infection within 4 weeks before the first radiotherapy treatment, or active pulmonary inflammation indicated by baseline imaging.
• History of interstitial lung disease, history of non-infectious pneumonitis, or Grade 3 or higher pulmonary dysfunction confirmed by pulmonary function testing.
• Active pulmonary tuberculosis, active hepatitis B infection, or active hepatitis C infection.
• Diagnosis of another malignancy before the first radiotherapy treatment, except for low-risk malignancies that have been adequately treated.
• Any other condition that, in the investigator's judgment, may affect patient safety, compliance, or the collection of study data.