Figure Three.

Age-adjusted incidence rates of HPV-related (panels A & C) and HPV-unrelated (panels B & D) head and neck squamous cell cancer between 1973 and 2006, stratified by age at diagnosis. The annual percent change in incidence for each age category is shown next to each line; * indicates slope with p<0.05. As per Chaturvedi et al¹⁷, HPV-related sites includes base of tongue, lingual tonsil, tonsil, oropharynx, and Waldeyer ring and HPV-unrelated sites includes other and unspecified parts of tongue, gum, floor of mouth, palate, and other parts of mouth. Graph generated with the assistance of Anil Chaturvedi, modified from similar graph in Chaturvedi et al. 2008 article.¹⁷