Loco-regional radiotherapy in de novo metastatic nasopharyngeal carcinoma with chemotherapy and immunotherapy: A real-world retrospective study from two cancer centers.

BACKGROUND: Immunochemotherapy has become the first-line treatment for initial diagnosed metastatic nasopharyngeal carcinoma (mNPC). Loco-regional radiotherapy combined with systemic chemotherapy significantly improves the survival. However, the safety and efficacy of loco-regional radiotherapy combined with immunochemotherapy remained unknown. METHODS: Patients with de novo mNPC who received immunochemotherapy followed by loco-regional radiotherapy were included from two cancer centers. Toxicity and treatment response were assessed using CTCAE 5.0 and RECIST 1.1, respectively. Overall survival (OS) and progression-free survival (PFS) were analyzed using the Kaplan-Meier method. RESULTS: From 2019 to 2021, a total of 16 patients were retrospectively analyzed. The median follow-up was 28 months (range 14-47 months). No one died. One-year, 2-year, and 3-year PFS rate was 93.8%, 58.4% and 50.1%, respectively. Radiotherapy-related acute severe (grade 3 or higher) toxicity was dermatitis (1/16, 6.3%) and mucositis (2/16, 12.5%). CONCLUSIONS: Loco-regional radiotherapy provided a promising efficacy with modest toxicity for patients with mNPC who received immunochemotherapy.