A Systematic Review of Risk Factors for Development, Recurrence, and Progression of Vulvar Intraepithelial Neoplasia

Objective Vulvar intraepithelial neoplasia (VIN) is a premalignant condition with high recurrence rates despite treatment. Vulvar intraepithelial neoplasia develops through separate etiologic pathways relative to the presence or absence of human papillomavirus (HPV) and TP53 mutations. This systematic review was conducted (1) to identify historical risk factors for the development, recurrence, and progression of VIN and (2) to critique these risk factors in the context of advances made in the stratification of VIN based on HPV or TP53 status. Materials and Methods A systematic search was performed on MEDLINE, Embase, Cochrane Database, PsychInfo, and CINAHL from inception to July 5, 2021. Three gynecologic oncologists independently evaluated the eligibility of studies based on predetermined inclusion and exclusion criteria, abstracted data, and then analyzed the relevant data. Results A total of 1,969 studies (involving 6,983 patients) were identified. Twenty-nine studies met inclusion criteria. The quality of evidence was low; primarily level 2b (Oxford Centre for Evidence-Based Medicine). Risk factors associated with the development of VIN include: smoking and coexisting vulvar dermatoses. Risk factors associated with recurrence include: smoking, multifocal disease, and positive surgical margins. Recent studies identified the presence of differentiated VIN/TP53 mutation as the most significant risk factor for both VIN recurrence and malignant progression. Conclusions The current body of evidence consists primarily of small retrospective observational studies. Well-designed retrospective case-control series and/or prospective observational studies are urgently needed. Ideally, future studies will collect standardized data regarding associated risk factors and stratify women with VIN based on HPV and TP53 status.