Locoregional radiotherapy improves survival outcomes in de novo metastatic nasopharyngeal carcinoma treated with chemoimmunotherapy

• Published in: ESMO open Vol. 8; no. 5; p. 101629
• Main Authors: Hu, Y.-J., Lu, T.-Z., Zhang, H., Fang, M., Chen, B.-J., Guo, Q.-J., Lin, S.-J., Feng, P., Wang, Y., Jiang, T.-C., Gong, X.-C., Pan, J.-J., Li, J.-G., Xia, Y.-F.
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-10-2023; Elsevier
• Subjects: de novo metastatic nasopharyngeal carcinoma; Epstein–Barr virus DNA; immunotherapy; locoregional radiotherapy; Original Research; locoregional radiotherapy; Epstein–Barr virus DNA; de novo metastatic nasopharyngeal carcinoma; immunotherapy
• ISSN: 2059-7029; 2059-7029
• DOI: 10.1016/j.esmoop.2023.101629

We aimed to investigate the efficacy of locoregional radiotherapy (LRRT) in patients with de novo metastatic nasopharyngeal carcinoma (dmNPC) receiving chemotherapy combined with anti-programmed cell death receptor-1 monoclonal antibodies (anti-PD-1 mAbs) as first-line treatment and identify optimal candidates for LRRT.
We enrolled patients with dmNPC receiving platinum-based palliative chemotherapy and anti-PD-1 mAbs followed or not followed by LRRT from four centers. The endpoints were progression-free survival (PFS), objective response rate (ORR), and overall survival (OS). We used the inverse probability of treatment weighting (IPTW) to balance the baseline characteristics of the LRRT and non-LRRT groups to minimize selection bias before comparative analyses. Multivariate analyses were carried out using the Cox proportional hazards model.
We included 163 patients with dmNPC (median follow-up: 22 months). The median PFS was 20 months, and the ORR was 92.0%; the median OS was not achieved. After IPTW adjustments, patients who received LRRT had a significant survival benefit over those not receiving LRRT (median PFS: 28 versus 15 months, P < 0.001). The Epstein–Barr virus DNA (EBV DNA) level after four to six cycles of anti-PD-1 mAbs [weighted hazard ratio (HR): 2.19, 95% confidence interval (CI) 1.22-3.92, P = 0.008] and LRRT (weighted HR: 0.58, 95% CI 0.34-0.99, P = 0.04) were independent prognostic factors. Patients with undetectable EBV DNA levels after four to six cycles of anti-PD-1 mAbs (early EBV DNA clearance) benefitted from LRRT (HR: 0.41, 95% CI 0.22-0.79, P = 0.008), whereas those with detectable levels did not (HR: 1.30, 95% CI 0.59-2.87, P = 0.51).
Palliative chemotherapy combined with anti-PD-1 mAbs followed by LRRT was associated with improved PFS in patients with dmNPC, especially for patients with early EBV DNA clearance.
•Patients with dmNPC receiving chemotherapy plus anti-PD-1 mAbs had an ORR of 92.0% and a median PFS of 20 months.•Chemotherapy plus anti-PD-1 monoclonal antibodies followed by LRRT improves survival outcomes.•Early clearance of EBV DNA is a biomarker for identifying suitable LRRT candidates in the era of immunotherapy.