Biopsy‐verified vulvar lichen sclerosus and the risk of non‐vulvar cancer: A nationwide cohort study

Abstract

AbstractVulvar lichen sclerosus (VLS) is a chronic inflammatory mucocutaneous disease known to be associated with human papillomavirus‐independent vulvar squamous cell carcinoma. Evidence on the association with other types of cancer, however, is sparce. We conducted a large nationwide cohort study examining the incidence of non‐vulvar cancers among women with biopsy‐verified VLS compared with the general female population. By using the nationwide Pathology Registry, we identified all women in Denmark with a biopsy‐verified VLS diagnosis during 1978–2019 (n = 16,921). The cohort was followed up in the Danish Cancer Registry until 2022 for a subsequent non‐vulvar cancer diagnosis. Standardized incidence ratios (SIRs) were computed with 95% confidence intervals (CIs) as relative risk estimates of all specific non‐vulvar cancer sites. Compared with general female population rates, women with biopsy‐verified VLS had decreased rates of several non‐vulvar cancers, including HPV‐related cancers (combined estimate: SIR = 0.5; 95% CI: 0.3–0.7), and lung (SIR = 0.6; 95% CI: 0.5–0.7), liver (SIR = 0.5; 95% CI: 0.2–0.9), and thyroid cancer (SIR = 0.5; 95% CI: 0.3–0.9). The decreased SIRs tended to sustain throughout the follow‐up period following the VLS diagnosis. This large nationwide cohort study shows that women with biopsy‐verified VLS may have a long‐term reduced risk of developing HPV‐related (cervical, vaginal, oropharyngeal, and anal) and smoking‐associated cancers (lung, liver, and cervical) as well as thyroid cancer. Future studies focusing on the mechanisms behind the decreased cancer risk are needed.