Outcomes Among Patients With Mucosal Head and Neck Squamous Cell Carcinoma Treated With Checkpoint Inhibitors

Abstract

Immune checkpoint inhibitors (CPIs) are now part of standard therapy for patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) because of improved outcomes compared with chemotherapy in clinical trials. However, data on outcomes in patients with HNSCC in the general population who are treated with CPIs remain limited. To assess response rates, survival outcomes, and associations with key clinical covariates in a large, contemporary cohort of patients with recurrent or metastatic mucosal HNSCC who were treated with CPIs with or without chemotherapy. This retrospective cohort study included patients older than 18 years who received CPI-based therapy for recurrent or metastatic HNSCC at the University of Pennsylvania from January 1, 2015, through August 15, 2021. Clinical and survival data were abstracted through medical record review. Treatment with CPIs with or without chemotherapy for a diagnosis of HNSCC. The main outcomes were overall survival, progression-free survival, and response rates. Overall survival and progression-free survival were estimated by Kaplan-Meier methods. Multivariable Cox proportional hazards regression was used to examine associations of key clinical variables with survival; a χ2 test and logistic regression were used to assess associations with response rate. The study cohort consisted of 212 patients, of whom 165 (77.8%) were male, 148 (69.8%) were former or current smokers, and 66 (31.1%) had an Eastern Cooperative Oncology Group (ECOG) performance status of 2 or greater; median age was 63.2 years (IQR, 57.2-71.2 years). Primary tumor sites included the oropharynx (99 [46.7%]), oral cavity (61 [28.8%]), and larynx or hypopharynx (52 [24.5%]). Most (126 [59.4%]) received CPI as first-line systemic therapy, and 23 (10.8%) received combination CPI with chemotherapy. The overall response rate was 30.1%. Estimated 1-year overall survival was 51.8% (95% CI, 44.5%-58.8%), and estimated 1-year progression-free survival was 9.4% (95% CI, 5.0%-15.5%). Median overall survival was 12.9 months (IQR, 4.1-36.5 months), and median progression-free survival was 3.9 months (IQR, 1.9-17.8 months). Non-oral cavity primary site (vs oral cavity) was associated with improved overall survival (human papillomavirus-positive oropharynx: hazard ratio [HR], 0.567 [95% CI, 0.335-0.960]; all other sites: HR, 0.491 [95% CI, 0.298-0.810]), and T category of 4 at presentation (HR, 1.594; 95% CI, 1.062-2.394) and an ECOG performance status greater than 1 (HR, 2.720; 95% CI, 1.866-3.964) were associated with worse overall survival. In this cohort study of patients with recurrent or metastatic HNSCC who received CPI therapy, the overall response rate was 30.1%. Patients with oral cavity cancer had worse overall survival compared with patients with HNSCC of other subsites. These findings support the use of CPI therapies for first- or second-line treatment of recurrent or metastatic HNSCC.