Risk of Vulvar Squamous Cell Carcinoma in Lichen Sclerosus and Lichen Planus: A Systematic Review

ABSTRACT Objectives: The objectives of this study were to determine: 1) the prevalence of lichen sclerosus (LS) and lichen planus (LP) present in association with vulvar squamous cell carcinoma (VSCC), and 2) the incidence and absolute risk of developing VSCC in LS and LP. Methods: A search was performed of MEDLINE, EMBASE and CINAHL databases. Three independent reviewers screened articles published before September 1, 2020, first on title/abstract and then on the full text. Women with a history of VSCC, human papillomavirus, smoking, or autoimmune disease were excluded. Newcastle-Ottawa observational study scales were used to assess the risk of bias and methodological quality of the included studies. Of the 3132 studies assessed, 31 were selected for analysis. Due to study heterogeneity, a qualitative synthesis was conducted. Results: The prevalence of LS and LP in association with VSCC ranged from 0% (95% CI 0–5) to 83% (95% CI 36–100) and 1% (95% CI 0–7) to 33% (95% CI 4–78), respectively. The incidence of VSCC ranged from 1.16 (95% CI 0.03-6.44) to 13.67 (95% CI 5.50–28.17) per 1000 person-years for LS. The absolute risk of developing VSCC in patients ranged from 0.0% (95% CI 0.0–5.52) to 21.88% (95% CI 9.28–39.97) with LS and was 1.16% (95% CI 0.1–4.1) with LP. Incidence was not calculable for LP owing to study characteristics. Conclusions: This review provides evidence that there is an increased risk of developing VSCC in women with LS, while associations with LP are less clear. Early identification, treatment, and long-term follow-up are essential to prevent potential malignant progression of these vulvar dermatoses.