Human papillomavirus genotype prevalence in invasive vaginal cancer from a registry-based population

Abstract

Objective: To describe the human papillomavirus (HPV) genotype distribution in invasive vaginal cancers diagnosed before the introduction of the HPV vaccine and evaluate if survival differed by HPV status.

Methods: Four population-based registries and three residual tissue repositories provided formalin-fixed, paraffin-embedded tissue from microscopically confirmed primary vaginal cancer cases diagnosed between 1994 and 2005 that were tested by L1 consensus polymerase chain reaction with type-specific hybridization in a central laboratory. Clinical, demographic, and all-cause survival data were assessed by HPV status.

Results: Sixty cases of invasive vaginal cancer were included. Human papillomavirus was detected in 75% (45) and 25% (15) were HPV-negative. HPV 16 was most frequently detected (55% [33/60]) followed by HPV 33 (18.3% [11/60]). Only one case was positive for HPV 18 (1.7%) Multiple types were detected in 15% of the cases. Vaginal cancers in women younger than 60 years were more likely to be HPV 16- or HPV 18-positive (HPV 16 and 18) than older women, 77.3% compared with 44.7% (P=.038). The median age at diagnosis was younger in the HPV 16 and 18 (59 years) group compared with other HPV-positive (68 years) and no HPV (77 years) (P=.003). The HPV distribution did not significantly vary by race or ethnicity or place of residence. The 5-year unadjusted all-cause survival was 57.4% for women with HPV-positive vaginal cancers compared with 35.7% among those with HPV-negative tumors (P=.243).

Conclusion: Three fourths of all vaginal cancers in the United States had HPV detected, much higher than previously found, and 57% could be prevented by current HPV vaccines.

Figure 1. HPV Genotype Distribution in Vaginal Cancer Cases (n = 60) HPV Typing of Cancers Study

Fig 1*Multiple types includes human papillomavirus (HPV) 16/33 (n = 5 56%) HPV 16 / 35 (n = 1, 11%) HPV 16/66 (n = 1, 11%) HPV 16/81 (n = 1, 11%), HPV 51 / 82 (n = 1, 11%).

Figure 2

5-year all-cause survival by HPV status among vaginal cancer patients. Note: Five-year unadjusted survival estimates are presented as Kaplan-Meier estimates with statistical testing performed using the log-rank test.