Reduced-Dose Versus Conventional-Dose Intensity-Modulated Radiation Therapy in Locally Advanced Nasopharyngeal Carcinoma With Remission After Induction Chemotherapy and Immunotherapy: A Multicenter, Phase III Clinical Trial
To explore the efficacy and safety of reduced-dose radiotherapy combined with concurrent chemotherapy and immunotherapy in stage Ⅳa (AJCC 8th,) locally advanced nasopharyngeal carcinoma patients who are sensitive to induction chemoimmunotherapy (assessed as complete response \[CR\]/partial response \[PR\] by imaging, with EBV DNA copy number reduced to zero or below the lower limit of detection), so as to provide a new treatment option for these patients.
• Histologically and/or cytologically confirmed nasopharyngeal non-keratinizing carcinoma (differentiated or undifferentiated type, i.e., WHO classification Type II or Type III).
• Clinical stage: AJCC 8th edition staging: T4N0-2M0, T1-4N3M0 (stage IVa); AJCC 9th edition staging: T4N0-2M0, T1-4N3M0 (stage III).
• After 3 courses of platinum-based chemotherapy combined with immunotherapy as induction treatment, the efficacy is assessed as PR or CR by nasopharyngoscopy and enhanced MRI of nasopharynx + neck, with EBV DNA reduced to zero or below the lower limit of detection.
• Age: 18-70 years old.
• PS/ECOG score (performance status score of 0 or 1).
• Adequate organ function:
‣ Hematology: White blood cell count ≥ 4000/μL, neutrophil count ≥ 2000/μL, hemoglobin ≥ 9 g/dL, platelet count ≥ 100000/μL;
⁃ Liver function: Bilirubin ≤ 1.5 × upper limit of normal (ULN) (patients with known Gilbert's disease and serum bilirubin level ≤ 3 × ULN are eligible), AST and ALT ≤ 1.5 × ULN, and alkaline phosphatase ≤ 1.5 × ULN; albumin ≥ 3 g/dL;
⁃ Renal function: Serum creatinine ≤ 1.5 × ULN or creatinine clearance ≥ 60 mL/min calculated by the Cockcroft-Gault formula.
⁃ Proteinuria: Urine protein/creatinine ratio (UPC ratio) \< 1.0. For those with UPC ratio ≤ 0.5, no further examination is required; for those with UPC ratio \> 0.5, further testing showing 24-hour urine protein \< 1000 mg is eligible.
• Note: The UPC ratio of random urine is an estimate of 24-hour urine protein quantification, and the two have a good correlation. The UPC ratio can be calculated using the following formulas:
• i. Urine protein/urine creatinine (if both protein and creatinine are in mg/dL); ii. (Urine protein) × 0.088/urine creatinine (if urine creatinine is in mmol/L).
• e) Coagulation function: International normalized ratio (INR) ≤ 1.5, activated partial thromboplastin time (APTT) ≤ 1.5 × ULN.
• Patients have signed the informed consent form and are willing and able to comply with the study's scheduled visits, treatment plans, laboratory tests, and other study procedures