It is universally accepted that high-risk human papillomavirus (HR-HPV) is the cause of cervical dysplasia and cancer. More recently it has been shown that HPV is also a marker of clinical outcome in oropharyngeal cancer. However, contemporary information is lacking on both the prevalence of HPV infection in vulvar cancer (VSCC) and the influence of HPV-status on the prognosis of this malignancy.
We retrieved tissue from all cases of VSCC diagnosed between 01/01/2008 and 31/12/2009 from a regional (NHS Greater Glasgow and Clyde) pathology biobank. All tissue underwent pathology review and clinical variables were extracted from electronic records. HPV genotyping using the Optiplex HPV Genotyping assay was preformed. This assay detects 24 HPV types including all established high-risk types. Rates of overall survival (OS) and progression-free survival (PFS) were estimated by the Kaplan–Meier method. Cox proportional-hazards models were used to estimate hazard ratios.
Valid HPV results were obtained for 62/66 cases of VSCC; HPV infection was present in 52% cases (32/62) and all types identified were HR-HPV types. As age increased, VSCC cases were less likely to be associated with HR-HPV (OR 0.51 95% CI 0.33-0.80, p trend=0.003). The mean follow-up time was 6 years. In the Kaplan-Meier analysis, women with HR-HPV positive VSCC had better OS (log-rank test p=0.01) and PFS (log-rank test p=0.0001). The 5-year rates of OS were 78% in the HR-HPV positive group and 49% in the HPV negative group. The 5-year rates of PFS were 87% in the HR-HPV positive group and 47% in the negative group. After adjustment for age and cancer stage, patients with HPV positive tumours had a 67% reduction in risk of death (hazard ratio, 0.33; 95% CI 0.12-0.80, p=0.001) and an 83% reduction in risk of disease progression (hazard ratio, 0.18; 95% CI 0.07-0.48, p=0.01) compared to HPV negative tumours.
HPV infection is common in vulvar cancer, especially in the young. HPV positivity is strongly associated with a better prognosis in patients with vulvar cancer even after adjustment for age and cancer stage.