The goal of this clinical trial is to learn if hypofractionated radiotherapy works to shorten the treatment time without increasing the side effects in patients of thymic epithelial tumors. The main questions it aims to answer are:

• Does Hypofractionated radiotherapy provide better results?
• Can hypofractionated radiotherapy reduce toxic and side effects compared with conventional radiotherapy? Researchers will compare the efficacy and safety of hypofractionated radiotherapy after thymic tumor surgery.

Participants will:

• Receive hypofractionated radiotherapy or conventional radiotherapy
• Visit the hospital regularly once every 12 weeks for checkups and tests

According to the World Health Organization histological classification system, thymic epithelial tumors (TET) are divided into thymoma and thymic carcinoma. Surgery is the main treatment for thymic tumors, and radiotherapy (RT), as an important auxiliary method of surgery, also plays an irreplaceable role in all stages of thymoma.

Hypofractionated radiotherapy is a common mode of radiotherapy for thoracic tumors. Unlike conventional radiotherapy, hypofractionated radiotherapy has a higher single dose and a shorter course of treatment. Because it improves the treatment efficiency, it can reduce the treatment time of patients and medical institutions and the cost of patients.

In the postoperative radiotherapy stage, conventional radiotherapy and hypofractionated radiotherapy were used. The course of hypofractionated radiotherapy was shorter than that of conventional radiotherapy. Patients chose to accept hypofractionated radiotherapy as the hypofractionated group, but not the conventional group.

Inclusion Criteria:

1. Patients must provide written informed consent.
2. 18 years old ≤ age <75 years old.
3. Thymoma confirmed by pathology: type A, type AB, type B1, type B2, type B3. Thymic carcinoma. Patients with previous thymectomy were required to have complete surgical related data.
4. Masaoka⁃Koga ⁃ stage Ⅰ-Ⅲ
5. ECOG performance status 0-2.
6. Expected survival time > 1 year.
7. Participants of childbearing age must agree to use effective contraception during the trial; In women of childbearing age, a serum or urine pregnancy test must be negative.
8. Patients who are not lactating.
9. Sufficient bone marrow reserve and good function of important organs.

Exclusion Criteria:

1. patients with prior thoracic radiotherapy;
2. diseases not suitable for radiotherapy, such as recent myocardial infarction, active congestive heart failure;
3. Uncontrolled infectious disease or other serious medical or mental illness that may interfere with care
4. Patients with other malignant tumors that are not under stable control;
5. Known history of mental illness, substance abuse, alcohol or drug abuse.
6. Other conditions deemed unsuitable for enrollment by the attending physician.