Expression of PDL-1 between primary and recurrent/metastatic head and neck squamous cell carcinoma: A bi-institutional retrospective concordance analysis (CONCORDL-1 study)

Immune checkpoint inhibitors (ICIs) have demonstrated efficacy in the treatment of recurrent and/or metastatic (RM) head and neck squamous cell carcinoma (HNSCC) Keynote 048 highlighted the relevance of PD-L1 Combined Positive Score (CPS) as a predictive biomarker for ICIs treatment, but challenges persist regarding ideal assessment and concordance between primary and relapsing tumor has not been determined.