Neutrophil‐to‐Lymphocyte Ratio and Pembrolizumab Outcomes in Oral Cavity Squamous Cell Carcinoma

Abstract Objective To determine the relationship between pretreatment neutrophil‐to‐lymphocyte ratio (NLR) and 6‐month progression‐free survival (PFS)/2‐year overall survival (OS) among patients with recurrent or metastatic (R/M) oral cavity cancer on pembrolizumab. Study Design This study was a retrospective, observational study performed at a tertiary care academic center. Setting Participants included patients with oral cavity squamous cell carcinoma (OCSCC) who began pembrolizumab treatment at the University of California, San Francisco between May 2016 and May 2022. Methods The primary outcome was a 6‐month PFS. The secondary outcome was a 2‐year OS. NLR was treated as a continuous variable. Disease progression was determined using radiographic criteria, adopted from the Response Evaluation Criteria in Solid Tumors. Results Fifty‐two patients with OCSCC were included. Immune checkpoint inhibitor (ICI) indication was recurrence/metastasis for all patients. The median pretreatment NLR was 5.7 (interquartile range: 3.6‐7.6). Twenty‐seven (55%) patients received pembrolizumab alone. Of those receiving treatment for R/M prior to ICI, 9 (18%) received salvage surgery and adjuvant therapy, 2 (4%) received chemotherapy alone, 1 (2%) received chemoradiation, and 10 (20%) received salvage surgery. Nineteen (36.5%) patients had distant metastases at the start of ICI. Six‐month PFS was 46%. Two‐year OS was 44%. NLR was independently associated with 6‐month PFS [hazard ratio, HR: 1.05 (95% confidence interval, CI: 1.01‐1.11), P = .028] and 2‐year OS [HR: 1.12 (95% CI: 1.05‐1.20), P < .001]. Conclusion Higher pretreatment NLR was associated with poorer 6‐month PFS and 2‐year OS in OCSCC patients treated with pembrolizumab.