The goal of this clinical trial is to learn whether postoperative radiotherapy can delay disease recurrence in patients with early-stage oral squamous cell carcinoma who have high-risk factors. The main question it aims to answer is: Is the clinical outcome of early-stage tongue squamous cell carcinoma patients with risk factors after tumor enlargement resection receiving postoperative radiotherapy better than that of patients with simple follow-up observation? How is the safety? Researchers will compare the postoperative radiotherapy group and the simple follow-up observation group to see if there are differences between the two groups in terms of 3-year disease-free survival rate, 5-year disease-free survival rate, overall survival rate, toxicity events, and quality of life.

Participants of postoperative radiotherapy group will receive postoperative radiotherapy 6-8 weeks after surgery.

Inclusion Criteria:

1. Age ≥ 18 years old and ≤ 70 years old, gender not limited;
2. Newly treated patients (who have not undergone radiotherapy, chemotherapy, or targeted therapy before);
3. Complete resection of the tumor with naked eye and no residual tumor observed in postoperative pathology;
4. The lesion is limited to the anterior 2/3 of the tongue (active part of the tongue);
5. Postoperative pathological diagnosis was squamous cell carcinoma of the tongue;
6. According to AJCC 8th edition, the pathological TNM staging is T1-2N0M0;
7. Having at least one risk factor: vascular cancer thrombus, nerve invasion, moderate or low differentiation;
8. The general status score of the Eastern Cancer Collaboration Group (ECOG) is 0-2 points;
9. Not participating in other clinical trials within the previous 4 weeks prior to screening; If other trials fail to screen cases, but meet the requirements of this trial, they can be enrolled.

Exclusion Criteria:

1. Patients who invade the oropharynx, mouth floor, cheeks, neck, and other organs;
2. Have received chemotherapy or other anti-tumor drugs;
3. Previously received radiation therapy for the head and neck area;
4. Patients with active autoimmune diseases that require systemic treatment in the past;
5. Pregnant or lactating women;
6. Individuals with acute infections that are difficult to control;
7. Patients with drug abuse, drug abuse, long-term alcoholism and AIDS;
8. The subjects also have other known invasive malignant tumors (excluding those with no evidence of tumor recurrence through treatment and a duration of more than 2 years);
9. Researchers believe that there are other conditions that hinder patients from participating in this trial.