Risk of oral tongue cancer among immunocompromised transplant recipients and human immunodeficiency virus-infected individuals in the United States.

Background: Oral tongue cancer incidence has increased among whites in the United States; however, the cause remains unknown. If an infectious agent is implicated, then elevated risk would be expected among immunosuppressed individuals.
Methods: By using population-based registry linkage information from the US Transplant Cancer Match and human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) Cancer Match studies, the authors examined the risk of oral tongue squamous cell carcinoma (SCC) among immunocompromised transplantation recipients and HIV-infected individuals. In addition, the risks of oropharyngeal SCC (strongly related to human papillomavirus infection; modestly affected by immunosuppression), other tobacco/alcohol-related oral cavity SCCs (not thought to be infection/immunosuppression-related), and non-Hodgkin lymphoma of oral cavity/pharynx (strongly related to Epstein-Barr virus; profoundly affected by immunosuppression) were evaluated.
Results: Compared with the general population, the risk of non-Hodgkin lymphoma was strongly increased (standardized incidence ratio [SIR] > 8.0). The risk of all SCCs was modestly and similarly elevated among transplantation recipients (SIR range, 2.2-2.7; P _{heterogeneity}  = .2); whereas, among HIV-infected individuals, the risk of oral tongue SCC was higher compared with the risk of other SCCs (SIR, 3.0 vs 1.7 [for oropharyngeal SCCs] and 2.3 [for other oral cavity SCCs]; P _{heterogeneity}  < .001). The risk of SCCs was significantly higher among men, older individuals, and whites; and risk increased with the time since transplantation/AIDS onset. The risk of oral tongue SCC was significantly higher among HIV-infected men who have sex with men compared with the average risk in HIV-infected individuals (adjusted incidence rate ratio = 2.0).
Conclusions: Similar modest increases in the risk of oral tongue and other oral cavity SCCs do not suggest that an infectious agent or exposure profoundly affected by immunosuppression underlies the increase in oral tongue cancer. Cancer 2018;124:2515-22. © 2018 American Cancer Society.
(© 2018 American Cancer Society.)