Postoperative adjuvant immunotherapy versus standard of care in resectable locally advanced head and neck squamous cell carcinoma with intermediate- and high-risk factors: a real-world retrospective study

Improving the prognosis of patients with LA-HNSCC who have intermediate- and high-risk factors has long been a priority for head and neck surgeons. Immunotherapy, particularly programmed cell death protein 1 (PD-1) inhibitor, has shown promise. However, there are currently no reports on the use of PD-1 inhibitors for postoperative adjuvant treatment of these patients. This retrospective study included 59 postoperative intermediate- and high-risk patients with LA-HNSCC. These patients were divided into two groups: a standard therapy group, consisting of patients who received only postoperative risk-adapted adjuvant (chemo)radiation (n = 34), and an adjuvant immunotherapy group, consisting of patients who received adjuvant immunotherapy as a follow-up maintenance regimen after the standard of care (n = 25). Progression-free survival (PFS) and overall survival (OS) by the Response Evaluation Criteria for Solid Tumors was the main outcome. The 2-year PFS and OS rates in the adjuvant immunotherapy group were 80.0% and 95.0%, respectively, compared to 62.1% (χ ²  = 2.465, P  = 0.116) and 79.3% (χ ²  = 2.434, P  = 0.119) in the standard therapy group. Stratified analysis showed that the 2-year PFS rate for patients in the adjuvant immunotherapy group with programmed death ligand 1 (PD-L1) combined positive score (CPS) ≥ 20 significantly improved compared to the standard therapy group (92.9% vs. 62.1%, χ ²  = 4.644, P  = 0.031). No serious immune-related adverse events were detected in the adjuvant immunotherapy group. Our study suggests administering PD-1 inhibitor as adjuvant therapy after standard of care shows a trend towards improving 2-year PFS in postoperative intermediate- and high-risk patients with LA-HNSCC. This trend is more pronounced in patients with a CPS of 20 or higher. Future clinical trials are needed to verify these results.