Yoon‐Jung Kang, Megan Smith, Ellen Barlow, Kate Coffey, Neville Hacker, Karen Canfell

The aim of this study was to assess trends in the age-specific incidence of vulvar cancer in 13 high-income countries satisfying a priori conditions regarding the availability of cancer registry data over a 20 year period; these were Canada, USA, 9 European countries, Australia and Japan. Five-yearly incidence and population at risk were obtained from Cancer Incidence in Five Continents for the years 1988-1992 (Volume 7) to 2003-2007 (Volume 10). The 5-yearly average percent change (AvPC) over the 20-year period and standardised rate ratios (SRRs) for 2003-2007 vs. 1988-1992 were used to assess changes in the age-standardised incidence rates of vulvar cancer for all ages, and for <60 years and 60+ years. During the study period, the 5-yearly AvPC across the 13 countries increased by 4.6% (p=0.005) in women of all ages, and 11.6% (p=0.02) in those <60 years. No change was observed in women aged 60+ years (5-yearly AvPC=0.1%, p=0.94). The SRR for 2003-2007 vs 1988-1992 was significantly elevated in women <60 years of age (SRR=1.38, 95% CI: 1.30-1.46), but not in women of 60+ years (SRR=1.01, 95% CI: 0.97-1.05). The increase in incidence in women <60 years of age drove a significant increase in the overall SRR in women of all ages (SRR=1.14, 95% CI: 1.11-1.18). The findings are consistent with changing sexual behaviours and increasing levels of exposure to HPV in cohorts born around/after 1950, but younger cohorts offered HPV vaccination are likely to receive some protection against developing vulvar cancer in the future. This article is protected by copyright. All rights reserved.