Comparison of induction chemotherapy with/without PD-1 inhibitors followed by concurrent chemoradiotherapy in locally advanced head and neck squamous cell carcinoma.

[BACKGROUND] Locally advanced head and neck squamous cell carcinoma (LA HNSCC) remains a disease with a challenging prognosis. Concurrent chemoradiotherapy has long been the standard of care, yet efforts to enhance outcomes through the addition of induction or adjuvant therapies have largely failed. Recently, immune checkpoint inhibitors, particularly PD-1 inhibitors, have demonstrated efficacy in managing HNSCC, becoming a first-line treatment for recurrent/metastatic cases. This study aims to evaluate whether adding PD-1 inhibitors to induction chemotherapy can improve long-term outcomes in newly diagnosed LA HNSCC patients.

[PATIENTS AND METHODS] This retrospective analysis included 204 newly diagnosed LA HNSCC patients treated between February 2012 and February 2023. Patients were divided into two cohorts: TPI group (n=115), who received induction chemotherapy including PD-1 inhibitors, and TP group (n=89), who received induction chemotherapy alone. The primary outcome was overall survival (OS), while secondary outcomes included progression-free survival (PFS) and objective response rate (ORR). Baseline characteristics were balanced using overlap propensity score weighting. Survival analyses were conducted using the Kaplan-Meier method, and subgroup analyses employed Cox proportional hazards models.

[RESULTS] With a median follow-up of 29.23 months, baseline characteristics were balanced after weighting. The addition of PD-1 inhibitors significantly improved OS (HR: 0.11, 95% CI: 0.03-0.37, p<0.001) and PFS (HR: 0.43, 95% CI: 0.20-0.89, p=0.024). Furthermore, the TPI group showed a significant improvement in the best radiological responses (p=0.02). Subgroup analyses identified specific factors associated with enhanced PFS and OS.

[CONCLUSIONS] The addition of PD-1 inhibitors to induction chemotherapy significantly improves overall survival in patients with LA HNSCC, underscoring the potential for further clinical trials to refine and optimize treatment strategies.