Prevention and Treatment of Radiation-Induced Oral Mucositis in NPC With Houyanqing Oral Liquid

Inclusion Criteria: 1. Staged as Stage I-IV according to the 9th edition of the TNM Classification of Malignant Tumors formulated by the American Joint Committee on Cancer (AJCC) and the Union for International Cancer Control (UICC); 2. Age: 18 to 75 years old; 3. Karnofsky Performance Status (KPS) score ≥ 80 before treatment; 4. No oral diseases (such as oral mucositis or salivary gland damage) before radiotherapy; 5. Requiring radical radiotherapy; 6. The patient has signed the informed consent form and is willing and able to comply with the study's follow-up visits, treatment plan, laboratory tests, and other research procedures. Exclusion Criteria: 1. Patients with confirmed tumor recurrence, distant tumor metastasis, or who have received other anti-tumor treatments; 2. Previous history of head and neck radiotherapy; 3. Known allergy to the drugs used in this study (Houyanqing Oral Liquid, any conventional treatment drugs); 4. Local use of Houyanqing Oral Liquid, Recombinant Human Epidermal Growth Factor (rhEGF) Topical Solution, Vitamin B12 Solution, or Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF) mouthwash in the oral cavity within one month before enrollment; 5. Comorbidities requiring long-term treatment with immunosuppressive drugs, or systemic/local use of corticosteroids at immunosuppressive doses before enrollment; 6. HIV-positive patients; 7. Pregnant women or lactating women; 8. Patients with severe mental illnesses; 9. Patients with severe cardio-cerebrovascular diseases, endocrine disorders, infectious diseases, or other tumors.