Conclusions
The establishment of prevaccine HPV prevalence in the United States is critical to the surveillance of vaccine efficacy. Almost 80% of anal cancers were positive for the vaccine types HPV-16 or HPV-18, and in 70%, these were the only types detected, suggesting that a high proportion might be preventable by current vaccines.
Methods
Population-based archival anal cancer specimens were identified from Florida, Kentucky, Louisiana, and Michigan cancer registries and Surveillance, Epidemiology, and End
Objective
This study aimed to conduct a representative survey of human papillomavirus (HPV) prevalence and its genotype distribution in invasive anal cancer specimens in the United States. Materials and
Results
Among 146 unique invasive anal cancer cases, 93 (63.7%) were from women, and 53 (36.3%) were from men. Human papillomavirus (any type) was detected in 133 cases (91.1%) and 129 (88.4%) contained at least 1 high risk-type, most (80.1%) as a single genotype. Human papillomavirus type 16 had the highest prevalence (113 cases, 77.4%); HPV types 6, 11, 18, and 33 were also found multiple times. Among HPV-16-positive cases, 37% were identified as prototype variant Ep, and 63% were nonprototypes: 33% Em, 12% E-G131G, 5% Af1, 4% AA/NA-1, 3% E-C109G, 3% E-G131T, 2% As, and 1% Af2. No significant differences in the distributions of HPV (any), high-risk types, or HPV-16/18 were seen between sex, race, or age group. Conclusions: The establishment of prevaccine HPV prevalence in the United States is critical to the surveillance of vaccine efficacy. Almost 80% of anal cancers were positive for the vaccine types HPV-16 or HPV-18, and in 70%, these were the only types detected, suggesting that a high proportion might be preventable by current vaccines.