Metastatic Lymph Node Status Is Associated With Progression-Free Survival in Oral Cavity Squamous Cell Carcinoma Treated With Pembrolizumab.

Abstract

The prognostic implications of regional lymph node metastases at the initiation of immune checkpoint inhibitor (ICI) therapy in oral cavity squamous cell carcinoma (OCSCC) are not well defined. This study evaluated whether the presence of metastatic cervical lymph nodes at the start of pembrolizumab therapy was associated with progression-free or overall survival among patients with recurrent or metastatic (R/M) OCSCC. A retrospective cohort study was conducted at a tertiary academic medical center including patients with R/M OCSCC who initiated pembrolizumab between May 2016 and May 2022. Patients receiving fewer than three cycles were excluded. The presence of metastatic lymph node(s) at ICI initiation was analyzed as a dichotomous variable. The primary outcome was 6-month progression-free survival (PFS), and the secondary outcome was 2-year overall survival (OS). Disease progression was determined using RECIST-based radiographic criteria. Cox proportional hazards models adjusted for age, PD-L1 status, presence of distant metastases, and receipt of concurrent systemic therapy. Forty-five patients met inclusion criteria; all received pembrolizumab for R/M disease. Twelve patients (27%) had metastatic cervical lymph nodes at ICI initiation. On univariate analysis, nodal metastasis was associated with poorer 6-month PFS (p = 0.024). After adjustment for age, PD-L1 status, distant metastases, and concurrent systemic therapy, cervical nodal metastasis remained independently associated with inferior PFS (HR 5.12; 95% CI 1.30-20.2; p = 0.020). Presence of metastatic cervical lymph nodes at the start of pembrolizumab therapy was associated with reduced 6-month progression-free survival, suggesting regional disease burden may predict limited ICI benefit in R/M OCSCC.