Sep 29

PQA 07 - Head and Neck Cancer, Lung Cancer/Thoracic Malignancies, and Nursing and Supportive Care

3530 - Exploratory Study on Prophylactic Irradiation of Visible Lymph Nodes in Low-Risk Regions of Nasopharyngeal Carcinoma (VNRT): A Prospective Phase II Trial

03:45pm - 05:00pm ET

Poster Hall - Exhibit Hall A

Screen: 7

Presenter(s)

Wenjun Liao, PhD - Sichuan Cancer Hospital & Institute, Cancer Hospital affiliate to School of Medicine, University of Electronic Science and Technology of China, Chengdu,

W. Liao¹, Y. Deng¹, Y. Zhao¹, and S. Zhang²; ¹Department of Radiation Oncology, Sichuan Cancer Hospital & Institute, Sichuan Cancer Center; Cancer Hospital affiliate to University of Electronic Science and Technology of China, Chengdu, Sichuan, China, ²Department of Radiation Oncology, Sichuan Cancer Hospital& Institution, Sichuan Cancer Center, School of Medicine, University of Electronic Science and Technology of China, Chengdu, China

Purpose/Objective(s): Nasopharyngeal carcinoma (NPC) is characterized by a distinct pattern of lymph node (LN) metastasis. Although standard whole-cervical prophylactic irradiation (WNI) provides high regional control rates, it is accompanied by significant long-term toxicities. Recent de-escalation strategies have highlighted the safety of sparing specific low-risk regions from irradiation. Based on previous studies, we propose a novel strategy called Visible Lymph Node Irradiation for Low-Risk Cervical Levels (VNRT). This approach hypothesizes that by irradiating only radiologically visible LNs (short axis = 3 mm) in low-risk cervical regions, regional control can be maintained while further reducing toxicities. This study aims to evaluate the efficacy and safety of VNRT in selected NPC patients.

Materials/Methods: This study is a prospective, single-arm, Phase II clinical trial (ChiCTR2300067783). Eligible patients are aged =18 years with pathologically confirmed NPC, staged as T1-2/N0-1M0 or T3N0M0 according to the AJCC 8th Edition, and with a Karnofsky Performance Status of =70.Patients with T1-2N0 receive radiation therapy alone, while other patients receive cisplatin-based concurrent chemoradiotherapy. The key feature of target delineation is the modification of cervical lymph node level irradiation. The proposed VNRT includes two clinical target volumes (CTVs): lymph node levels of prophylactic irradiation (CTVln) and irradiation of all visible lymph nodes in low-risk cervical levels (CTVnd). The detailed delineation strategies are as follows: (i) For N0 patients and N1 patients with only ipsilateral or bilateral positive retropharyngeal lymph nodes, CTVln covers bilateral level II, and CTVnd includes all visible lymph nodes in bilateral levels III and Va. (ii) For N1 patients with positive lymph nodes in cervical level II, CTVln includes bilateral levels II and ipsilateral levels III and Va; CTVnd includes all visible lymph nodes located in ipsilateral levels IV and Vb, and contralateral levels III and Va. (iii) For N1 patients with positive lymph nodes in cervical levels II and III, CTVln includes bilateral levels II and ipsilateral levels III, IV, and V; CTVnd includes all visible lymph nodes located in contralateral levels III and Va. The primary endpoint is 2-year regional recurrence-free survival. Secondary endpoints include overall survival, distant metastasis-free survival, and patient-reported outcomes.

Results: Enrollment has been completed with a total of 20 patients. The study is currently in the follow-up phase.

Conclusion: This prospective Phase II study evaluates the efficacy and safety of VNRT, a novel de-escalation irradiation strategy that selectively targets visible lymph nodes in low-risk cervical regions, aiming to maintain regional control while reducing treatment-related toxicities in selected NPC patients.