Lichen Sclerosus: Incidence and Risk of Vulvar Squamous Cell Carcinoma.

BACKGROUND The association between lichen sclerosus and vulvar squamous cell carcinoma (VSCC) has long been recognized, but large epidemiologic studies are lacking. METHODS Data of women diagnosed with vulvar pathology in the Netherlands were retrieved from the Dutch Pathology Registry. All vulvar pathology reports of this historical cohort were reviewed to construct a research database, including 3,038 women with lichen sclerosus diagnosed between 1991 and 2011. The incidence rate of lichen sclerosus and the cumulative incidence of VSCC among women with lichen sclerosus were estimated. RESULTS Between 1991 and 2011, the incidence rate of lichen sclerosus increased from 7.4 to 14.6 per 100,000 woman-years. The median age at time of lichen sclerosus diagnosis was 59.8 years and the cumulative VSCC incidence was 6.7%. The 10-year VSCC incidence in women with lichen sclerosus was associated with concurrent vulvar intraepithelial neoplasia (VIN; 18.8% in women with VIN and 2.8% in women without VIN) and age at time of lichen sclerosus diagnosis (5.9% in women of ≥70 years, 3% in women between 50 and 70 years, and 1.8% in women <50 years). The effects of presence of VIN and age remained significant in adjusted Cox regression analysis. CONCLUSION This historical cohort showed a nearly 100% increase in incidence of lichen sclerosus between 1991 and 2011. Concurrent VIN and age ≥70 years at time of lichen sclerosus diagnosis are important risk factors for vulvar cancer development. IMPACT The incidence of lichen sclerosus is rising and special attention is needed in particular in women with concurrent VIN because of their high risk of cancer. Cancer Epidemiol Biomarkers Prev; 25(8); 1224-30. ©2016 AACR.