Neoadjuvant Immunotherapy and Chemoimmunotherapy Regimens in Head and Neck Cancer

IMPORTANCE: Neoadjuvant chemoimmunotherapy has high rates of pathologic response and improved prognosis among solid tumors. Its role in head and neck squamous cell carcinoma (HNSCC) remains understudied. OBJECTIVE: To summarize the efficacy associated with neoadjuvant chemoimmunotherapy regimens in HNSCC and to compare the efficacy associated with neoadjuvant chemoimmunotherapy vs immunotherapy alone in locoregionally advanced resectable HNSCC prior to definitive surgery. DATA SOURCES: A librarian-led systematic review was conducted using multiple electronic databases, including Medline, EMBASE, Cochrane Central Register of Controlled Trials, Cochrane Database of Systematic Reviews, and Scopus, following Preferred Reporting Items for Systematic Reviews and Meta- Analyses (PRISMA) guidelines. Databases were queried from inception to October 2024. STUDY SELECTION: Inclusion criteria included prospective interventional trials that have completed accrual, with results published in English. Only trials of resectable, treatment-naive HNSCC were included. Exclusion criteria included lack of reporting on pathologic response or Response Evaluation Criteria In Solid Tumors (RECIST) version 1.1 response. DATA EXTRACTION AND SYNTHESIS: Two investigators independently conducted title, abstract, and full-text reviews per PRISMA guidelines. Primary outcomes extracted were major pathologic response (MPR) and complete pathologic response (CPR) at surgery and complete response (CR) on imaging by RECIST 1.1. Secondary outcomes included 1-year overall survival (OS) and toxic effects. MAIN OUTCOMES AND MEASURES: A meta-analysis was performed using a binary random-effects model to determine the pooled proportion of primary outcomes in the immunotherapy and chemoimmunotherapy groups. Heterogeneity was reported as I2. RESULTS: A total of 751 patients (502 [77%] male; age range, 27-87 years) across 23 studies were included in the meta-analysis, including 357 patients (47%) who underwent chemoimmunotherapy, 102 patients (14%) who underwent dual-agent immunotherapy, and 292 patients (39%) who underwent single-agent immunotherapy. Pooled rates of MPR plus CPR were 66% (95% CI, 58%-73%; I2 = 0.59) for chemoimmunotherapy, 18% (95% CI, 6%-29%; I2 = 0.65) for dual-agent immunotherapy, and 6% (95% CI, 3%-9%; I2 < 0.01) for single-agent immunotherapy. Across all groups, 1-year OS rates ranged from 88% to 96% for single-agent immunotherapy, 88% to 96% for dual-agent immunotherapy, and 88% to 100% for chemoimmunotherapy. Grade 3 to 5 adverse events were reported in 61 of 210 patients (29%), 2 of 67 patients (3.0%), and 36 of 210 patients (17%) among the reporting studies in the single-agent immunotherapy, dual-agent immunotherapy, and chemoimmunotherapy groups, respectively. CONCLUSIONS AND RELEVANCE: These findings suggest that neoadjuvant chemoimmunotherapy regimens were associated with higher pathologic and radiographic response rates compared with immunotherapy alone in locoregionally advanced HNSCC. These results call for phase 3 trials comparing these neoadjuvant regimens head to head.