This study is a real-world study to observe the role of adjuvant radiotherapy in locally advanced recurrent high-risk thyroid cancer. The study included thyroid cancer that requires adjuvant radiotherapy to increase local control rate, excluding undifferentiated cancer. Local-regional recurrence free survival is the primary endpoint of the study.

Inclusion Criteria:

• Patients voluntarily join this study and sign an informed consent form;

• Age: ≥ 14 years old,<80 years old, male or female not limited;

• Thyroid cancer diagnosed by histopathology, including differentiated thyroid cancer, medullary carcinoma, poorly differentiated carcinoma, etc;

• High risk of local late recurrence, meeting any of the following criteria:

  1. The surgery did not achieve R0 resection;
  2. After neoadjuvant therapy;
  3. Pathological types with poor prognosis, such as poorly differentiated cancer, CASTLE, etc;
  4. Thyroid cancer with obvious extracapsular invasion, invading important structures such as the esophagus, trachea, and recurrent laryngeal nerve, requiring adjuvant radiotherapy;
  5. For patients with distant metastasis, researchers need to determine the value of local treatment;

• The main organ functions are normal;

• Good compliance and cooperation with follow-up.

Exclusion Criteria:

• Untreated thyroid cancer or thyroid cancer that has only undergone surgical biopsy;
• Within 5 years or simultaneously suffering from other active malignant tumors. Cured local tumors, such as skin basal cell carcinoma, skin squamous cell carcinoma, superficial bladder cancer, prostate carcinoma in situ, cervical carcinoma in situ, breast carcinoma in situ, can be included in the group;
• Previously received radiation therapy for the head and neck area;
• Pregnant or lactating women;
• There are other physical illnesses that affect patients' ability to receive standard treatment;
• According to the researcher's judgment, there may be other factors that could force the subject to terminate the study midway, such as suffering from other serious illnesses (including mental illnesses) that require concurrent treatment, severe abnormal laboratory test values, family or social factors that may affect the subject's safety or the collection of trial data;
• Individuals with claustrophobia who are unable to undergo radiation therapy;
• Other patients deemed unsuitable for inclusion by the treating physician.

Patients with high recurrence risk locally advanced thyroid cancer