PD-1 Inhibitors Combined with Chemotherapy versus Re-irradiation/chemoradiotherapy for Unresectable Locally Recurrent T3-4 Nasopharyngeal Carcinoma: A Retrospective Study.

Objective: To evaluate the efficacy, toxicity, and long-term outcomes of PD1 inhibitors plus chemotherapy versus re-irradiation/chemoradiotherapy in patients with unresectable locally recurrent T3-4 nasopharyngeal carcinoma (NPC). Methods: A retrospective analysis was conducted on 42 patients with recurrent nasopharyngeal cancer (NPC) after receiving immunochemotherapy or re-irradiation between February 2018 and May 2022 in Zhejiang Cancer Hospital. Overall survival (OS), progression-free survival (PFS), local recurrence-free survival (LRFS), and distant metastasis-free survival (DMFS) were determined using the Kaplan-Meier method, log-rank test, and Cox proportional hazard regression. Results: With a median follow-up duration of 28.7 months (ranging from 7.2 to 63.9 months), the 3-year OS rate was 23.3% in the re-irradiotherapy (RI) group (N = 24) and 59.6% in the immunochemotherapy (IC) group (N = 18) (p = 0.042). The 3-year PFS, LRFS, and DMFS rates were not significantly different between the two groups (PFS: 45.3% vs. 62.6%, P = 0.482; LRFS: 54.4% vs. 62.6%, P =0.891; DMFS: 89.8% vs. 100.0%, P = 0.489). The univariate analysis revealed that regimen (HR: 0.354, 95% CI: 0.130-0.962, P = 0.042) was significantly correlated with OS. Multivariate analysis also showed that treatment regimen (HR: 0.329, 95% CI: 0.12-0.970, P =0.044) was the only significant prognostic factor associated with OS. The most common late toxicities in the RI group were xerostomia, deafness, and nasopharyngeal necrosis. Of these, nasopharyngeal necrosis was present in 16 patients (66.7%) and in 10 patients (41.7%) at a grade 3 or above. Nasopharyngeal necrosis is the main cause of death in the RI group. In contrast, in the IC group, grade 3 or higher immune-related adverse events or late adverse events were not observed. Conclusions: For unresectable locally recurrent NPC, re-irradiation is an effective treatment; nevertheless, the survival obtains are usually surpassed by serious late complications. For these individuals, chemotherapy in addition to an anti-PD-1 checkpoint inhibitor may be a helpful course of treatment.