3700 - Efficacy of PD-1 Inhibitors Combined with Chemoradiotherapy in Locally Advanced Nasopharyngeal Carcinoma with High-Grade Radiological Extranodal Extension
Presenter(s)
Y. Zou1,2, W. Weili1,2, T. Zhao1,2, T. Zhou1,2, T. Chen1,2, L. Zhao1,2, H. Tang1,2, X. Chen2, J. Long1,2, and Y. Zeng3; 1Affiliated Hospital of Guizhou Medical University, Guizhou Province, China, 2Affiliated Tumor Hospital of Guizhou Medical University, Guizhou Province, China, 3Guiyang Public Health Treatment Center, Guizhou Province, China
Purpose/Objective(s): To evaluate the efficacy and safety of programmed death-1 (PD-1) inhibitors in locally advanced nasopharyngeal carcinoma (LANPC) with high-grade radiological extranodal extension (ENE).
Materials/Methods: We reviewed records of all LANPC patients with high-grade ENE treated at our institution from January 2018 to September 2022. Patients were divided into two groups based on treatment: the PD-1 group (n = 49) received PD-1 inhibitors plus induction chemotherapy followed by radiotherapy alone or concurrent chemoradiotherapy; the Standard group received TPF (docetaxel, cisplatin, and 5-fluorouracil) or GP (gemcitabine and cisplatin) induction chemotherapy followed by concurrent chemoradiotherapy. Propensity score matching was used to select 49 patients for the Standard group. SPSS version 25.0 was used for statistical analysis.
Results: After induction therapy, the PD-1 group showed higher regression rates of cervical lymph nodes and overall tumor burden compared to the Standard group (Z = -2.10, P = 0.036; Z = -2.50, P = 0.012). The PD-1 group demonstrated superior 3-year event-free survival (EFS) and distant metastasis-free survival (DMFS) (91.8% vs. 69.4%, P = 0.005; 98.0% vs. 75.7%, P = 0.024). During induction chemotherapy, leukopenia and neutropenia were more frequent in the Standard group (Z = -3.42, P = 0.001; Z = -3.61, P < 0.001). Within the Standard group, the TPF regimen caused more severe leukopenia and neutropenia than the GP regimen (Z = -2.87, P = 0.004; Z = -3.35, P = 0.001). No significant differences in leukopenia or neutropenia were found between the GP regimen (Standard group) and the PD-1 group (Z = -0.81, P = 0.416; Z = -0.88, P = 0.377). The PD-1 inhibitor group had a higher incidence of grade 1-2 renal impairment (Z = -3.00, P = 0.003). During radiotherapy, the Standard group experienced higher rates of leukopenia, neutropenia, hemoglobin reduction, and gastrointestinal reactions (Z = -2.72, P = 0.007; Z = -3.10, P = 0.002; Z = -3.24, P = 0.001; Z = -3.96, P = 0.001). Within the PD-1 group, the subgroup receiving concurrent chemotherapy had higher incidences of leukopenia, neutropenia, hemoglobin reduction, and gastrointestinal reactions (Z = -2.67, P = 0.008; Z = -3.82, P < 0.001; Z = -1.97, P = 0.049; Z = -3.11, P = 0.002). Comparing the PD-1 subgroup with concurrent chemotherapy to the Standard group, no significant differences were found in leukopenia, neutropenia, hemoglobin reduction, or gastrointestinal reactions (all P > 0.05). The most common immune-related adverse event was hypothyroidism (51.0%). Multivariate analysis identified treatment in the PD-1 group as a protective factor for EFS.
Conclusion:
PD-1 inhibitor-based chemoradiotherapy enhances therapeutic efficacy and maintains a favorable safety profile in patients with LANPC presenting with high-grade ENE.