Optimization of Cervical Nodal CTV for Early and Medium Stage NPC

ISRT-NPC is a prospective, multicenter, open-label, noninferiority, phase III randomized controlled trial. A total of 488 patients will be randomly assigned in a 1:1 ratio to receive ISI or ERI. Randomization will be stratified by institution and N stage. Generally, in the ISI group, the high-risk CTV1 (dose: 60 Gy) includes a 1-cm expansion of the positive LN as well as the VIIa and the retrostyloid space above the bilateral transverse process of the atlantoaxial spine (C1), regardless of N status. The low-risk CTV2 (Dose: 50 Gy) covers the cervical nodal region with a 3-cm caudal expansion below the transverse process of C1 for N0 disease and a 3-cm expansion below the positive LN for positive LNs (at least covering the level II).

• Age between 18 and 75 years;
• Karnofsky performance status (KPS) score ≥ 70;
• Pathologically confirmed World Health Organization (WHO) type II-III NPC;
• TNM stage I-III (T1-3N0-2M0) according to the 8th American Joint Committee on Cancer / Union for International Cancer Control (AJCC/UICC) staging system with a maximum diameter (MAD) of cervical involved LNs ≤ 3 cm, namely LB-LN;
• Available baseline nasopharynx and neck computed tomography (CT) or magnetic resonance imaging (MRI) (strongly advocated) data (including functional MRI sequences) and measurable tumor lesions;
• All procedures for defining the tumor burden completed within 4 weeks of registration;
• Survival expectancy of at least 6 months;
• Normal marrow and organ function: hemoglobin ≥ 120 g/L, WBCs ≥ 4 × 109 /L, platelets ≥ 100 × 109 /L; liver and kidney function-related indicators within 1.25*the normal upper limit;
• Patient willingness to comply with the protocol;
• Patient willingness and ability to provide an informed consent form.