Global incidence, risk factors and trends of vulvar cancer: A country-based analysis of cancer registries.

Vulvar cancer is an uncommon malignancy. Vulvar cancer alarmed the public health problem in terms of the cost of diagnostic and medical treatments and psychical health of females. Our study aims to provide a thorough analysis of the global disease burden, related risk factors and temporal incidence trends of vulvar cancer in population subgroups. Data from Global Cancer Observatory and the Cancer Incidence in Five Continents Plus were used for the vulvar cancer incidence. Age-standardized rates (ASR) were used to depict the incidence of vulvar cancer. The 10-year trend of incidence was assessed using joinpoint regression with average annual percentage change and 95% confidence intervals in various age groups, while its correlations with risk factors were investigated using linear regression. Higher ASR were found in Western Europe (2.4), Northern America (1.9), Northern Europe (1.9), Australia and New Zealand (1.8) and Eastern Africa (1.4). The associated risk factors of higher vulvar cancer incidence were gross domestic product per capita, Human Development Index, higher prevalence of smoking, alcohol drinking, unsafe sex and human immunodeficiency virus infection. The overall trend of vulvar cancer incidence was increasing. An increasing trend was found in older females while a mixed trend was observed in younger females. The disease burden of vulvar cancer follows a bimodal pattern according to its two histologic pathways, affecting women in both developed and developing regions. Smoking cessation, sex education and human papillomavirus vaccination programs should be promoted among the general population. Subsequent studies can be done to explore the reasons behind the increasing trend of vulvar cancer.