Retrospective study of characteristics and outcomes of postradiation versus sporadic oral cavity squamous cell carcinoma

Postradiation oral cavity squamous cell carcinoma (OCSCC) is a common secondary malignant neoplasm affecting survivors of head and neck cancer. A retrospective study at Queen Elizabeth Hospital (Hong Kong, China) compared characteristics and outcomes of postradiation versus sporadic OCSCC. In this matched cohort study of 173 patients, postradiation OCSCC demonstrated significantly higher risk of locoregional relapse and mortality versus sporadic OCSCC, despite a higher proportion of patients with N0 disease. Postradiation OCSCC exhibited more adverse pathologic features, higher PD-1 expression, and higher gene expression of CD4 and TGF-β compared with sporadic OCSCC. The authors conclude that these findings suggest that the clinical and pathologic features of postradiation OCSCC are distinct from those of sporadic OCSCC, and further exploration of the role of immune checkpoint inhibitor therapy may be justified.