Elective Level Ib Irradiation in Nasopharyngeal Carcinoma Patients Based on the International Guidelines

Elective Level Ib Irradiation in Nasopharyngeal Carcinoma Patients Based on the International Guidelines: an Open-label, Non-inferiority, Multicentre, Randomised Phase 3 Trial

Currently, nasopharyngeal carcinoma (NPC) patients who had level II involvement with extracapsular extension (ECE), and/or had a maximum nodal axial diameter (MAD) of greater than 2cm in level II will be recommended to receive level Ib-covering IMRT according to the International Guidelines. Our previous study, which retrospectively analyzed a cohort of 390 patients, indicated that it should be safe and feasible for patients who only had at least one of the above two radiological features. Thus, the investigators conduct this non-inferior phase 3, randomized trial to further determine the feasibility of sparing level Ib in patients who had level II involvement with ECE, and/or had a MAD of greater than 2cm in level II.

Currently, nasopharyngeal carcinoma (NPC) patients who had level II involvement with extracapsular extension (ECE), and/or had a maximum nodal axial diameter (MAD) of greater than 2cm in level II will be recommended to receive level Ib-covering IMRT according to the International Guidelines. Our previous study, which retrospectively analyzed a cohort of 390 patients, indicated that it should be safe and feasible for patients who only had at least one of the above two radiological features. Thus, the investigators conduct this non-inferior phase 3, randomized trial to further determine the feasibility of sparing level Ib in patients who had level II involvement with extracapsular extension (ECE), and/or had a maximum nodal axial diameter (MAD) of greater than 2cm in level II.

Inclusion Criteria:

1. newly diagnosed, non-metastatic nasopharyngeal carcinoma histologically confirmed by biopsy;
2. the following conditions: ① involvement of level II LNs with extracapsular extension(ECE); ② level II LNs involvement with maximum nodal axial diameter (MAD) greater than 2 cm;
3. Eastern Cooperative Oncology Group (ECOG) score of 0 or 1.

Exclusion Criteria:

1. level Ib involvement with positive pathological results;
2. submandibular glands (SMGs) involvement;
3. involvement of structures that drain to level Ib as the first echelon site (the oral cavity, anterior half of nasal cavity involvement);
4. previous malignancy or other concomitant malignant disease.