RET Inhibitor for Neoadjuvant Therapy in Locally Advanced RET-altered Thyroid Cancer

Inclusion Criteria:

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

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

• Locally advanced thyroid cancer diagnosed by histopathology, including papillarythyroid carcinoma, medullary thyroid carcinoma, follicular thyroid carcinoma, poorlydifferentiated/poorly differentiated thyroid carcinoma, etc;

• RET alterations, including fusion and mutations;

• The definition of locally advanced thyroid cancer meets at least one of thefollowing criteria:

1. Local advanced thyroid cancer with estimated surgical difficulty and inabilityto R0/1 resection;

2. T4 thyroid cancer defined by AJCC: any size of tumor primary lesion or regionallymph node infiltration beyond the thyroid capsule to subcutaneous soft tissue,larynx, trachea, esophagus, or recurrent laryngeal nerve, tumor invasion of prevertebral fascia or wrapping around carotid or mediastinal blood vessels;

3. According to the imaging score, the resectable probability is less than 80%based on CT.

• At least one measurable lesion;

• For patients with distant metastasis, researchers need to determine whether patientswould benefit from surgery;

• Patients voluntarily undergo tumor tissue biopsy/surgery during enrollment andwithdrawal;

• Normal function of major organs.

Exclusion Criteria:

• Previously used RET inhibitors;

• There are multiple factors that affect the absorption of oral medication, such asinability to swallow, nausea and vomiting, chronic diarrhea, and intestinalobstruction;

• The patient refuses to undergo tumor tissue biopsy or surgery;

• Patients who are unsuitable for RET inhibitors or surgery.