ESTRO 2025 - Abstract Book

S1006

Clinical – Head & neck

ESTRO 2025

Conclusion: Over 80% of NPC patients survive without disease progression 24 months after treatment and are followed with a favorable sOS. Except for stage IVA, most patients achieving PFS24 share indistinguishable survival with the background population. Nonetheless, individuals with early recurrence experience markedly reduced survival. These notable outcome disparities underscore the value of PFS24 in NPC risk stratification, patient surveillance, and study design.

Keywords: nasopharyngeal carcinoma; surrogate endpoint

1973

Digital Poster Efficacy of immunotherapy in Epstein-Barr Virus-Negative Recurrent/Metastatic Nasopharyngeal Carcinoma: A Study from Non-High-Incidence Areas Lei Wang, Shiyou Li, Dongqin Liu, Xiao Ma, Ruiping Wu, Guifang Hu, Yi Yang, Yaoxiong Xia, Xiaoli Wang Department of Radiotherapy, Yunnan Cancer Hospital, The Third Affiliated Hospital of Kunming Medical University, Peking University Cancer Hospital Yunnan, Kunming, China Purpose/Objective: Background and Objectives: Nasopharyngeal carcinoma (NPC) is highly prevalent in South China and is closely associated with Epstein-Barr virus (EBV) infection. 20-30% of NPC patients still experience recurrence or metastasis after receiving radiotherapy and chemotherapy. Clinical studies from high-incidence areas of NPC have shown that immunotherapy combined with chemotherapy (ICT) for first-line treatment of recurrent/ metastatic NPC can significantly improve patients survival. However, the treatment situation and efficacy of ICT in EBV-negative recurrent/ metastatic NPC in non-high-incidence areas have been rarely reported. Material/Methods: The clinical data of EBV-negative recurrent/ metastatic NPC patients who received immunotherapy in Yunnan Cancer Hospital from August 2019 to March 2023 were retrospectively collected. Survival analysis was performed using the Kaplan-Meier method, and the log-rank test was used to compare the survival differences between groups. Results: A total of 31 EBV-negative recurrent/ metastatic NPC patients who received ICT were included in this study, with a median age of 49 years (ranging from 30 to 65 years). Among the 31 patients, 4 (12.9%), 4 (12.9%), and 23 (71.2%) patients underwent ICT treatment due to disease recurrence, local lesion recurrence combined with distant metastasis, and distant metastasis, respectively. Moreover, 13 (41.9%), 10 (32.3%), and 8 (25.8%) patients received ICT as first-line, second-line, and third-line or above treatments, respectively. The median progression-free survival (mPFS) and median overall survival (mOS) of all patients were 13.7 and 39.3 months, respectively. After treatment, 5 (16.1%) patients achieved complete remission, 7 (22.6%) patients achieved partial remission, 6 (19.4%) patients achieved stable disease, 7 (22.6%) patients had disease progression, and 6 (19.4%) patients had their disease status unevaluable. The objective response rate and disease control rate of all patients after treatment were 38.7% and 58.1%, respectively. In addition, the mPFS of patients with recurrence, distant metastasis, and recurrence combined with metastasis were not reached, 10.2 months, and 12.1 months, respectively. The most common adverse reaction in all patients was an increase in aspartate aminotransferase (22.6%). Conclusion: ICT treatment is safe and effective in EBV-negative recurrent/ metastatic NPC in non-high-incidence areas, with cases used as first-line, second-line, third-line, or above treatments. Patients with only disease recurrence have