Reduced-dose vs Standard-dose Irradiation for Low-risk Clinical Target Volume in Nasopharyngeal Carcinoma.

To evaluate the locoregional control, survival rate, toxicity, and quality of life in patients with nasopharyngeal carcinoma treated with reduced prophylactic irradiation doses to the Low-Risk Clinical Target Volume (CTV).

Inclusion Criteria: Newly diagnosed, untreated, non-distant metastatic, and non-keratinizing NPC; aged between 18 and 70 years; Eastern Cooperative Oncology Group performance score of 0-1; adequate hematologic function (neutrophil count ≥ 1.5 × 10\^9/L, platelet count ≥100×109/L, and hemoglobin≥ 90 g/L); adequate renal function (creatinine ≤ 1.5 upper limit of normal \[ULN\]) or calculated creatinine clearance (CrCl) ≥ 60 mL/min (Cockcroft-Gault formula); and adequate hepatic function (serum bilirubin ≤ 2.0×ULN, and alanine aminotransferase and aspartate aminotransferase ≤ 2.5×ULN). Exclusion Criteria: Previous chemotherapy treatment, surgery (except diagnostic) or radiotherapy to the neck or nasopharyngeal regions; previous malignancy (except for cured basal cell carcinoma or carcinoma in situ of the cervix); lactation or pregnancy; or severe coexisting illness. \-