LICHEN planus was associated with increased risks of oral, genital, and skin cancers in a nationwide Danish retrospective cohort study, with the greatest relative risks observed at anatomical sites affected by the condition. Although absolute cancer risks remained low, the findings suggest that site-specific malignancy should be considered during long-term care for patients with lichen planus.
Researchers analysed register-based data from 35,845 people diagnosed with lichen planus between 1978 and 2020, including 21,650 females and 14,195 males. Participants had no previous cancer diagnosis and were followed until death, emigration, or the end of 2023. Cancer incidence was compared with that of the general Danish population, with results assessed separately by sex.
Among females with lichen planus, the standardised incidence ratio (SIR) for lip cancer was 6.0 (95% CI: 3.3–10.0), while oral cavity cancer had an SIR of 7.5 (95% CI: 6.4–8.9) and tongue cancer an SIR of 6.8 (95% CI: 5.4–8.4). Vulvar cancer risk was also elevated (SIR: 2.6; 95% CI: 2.0–3.4). The overall pattern was similar in males. Site-specific analyses found that oral lichen planus was associated with a 9–14-fold higher risk of oral cancer, while genital lichen planus was associated with a 17–24-fold higher risk of genital cancer. Squamous cell carcinoma risk was slightly elevated among females (SIR: 1.4; 95% CI: 1.3–1.6).
Site-specific analyses found the strongest associations where lichen planus affected the corresponding anatomical region. Oral lichen planus was associated with a nine- to 14-fold increased risk of oral cancers, while genital lichen planus was linked to a 17- to 24-fold increased risk of genital cancers.
The study also identified a modestly increased risk of squamous cell carcinoma among females with lichen planus (SIR: 1.4; 95% CI: 1.3–1.6). Conversely, lung cancer incidence was lower in this group (SIR: 0.7; 95% CI: 0.6–0.8). The researchers reported that risk patterns remained consistent over follow-up.
Despite the elevated relative risks, the absolute risks of individual cancers over 20 years were comparatively low. Oral cavity cancer risk was 0.8% in females and 1.0% in males with lichen planus. Corresponding risks for tongue cancer were 0.5% and 0.6%, respectively.
The authors concluded that lichen planus was associated with increased risks of oral and genital cancers, alongside a smaller increase in skin cancer risk. The findings support consideration of site-specific cancer as a possible long-term complication. However, the observational design establishes associations rather than causation, and the study does not establish a specific surveillance schedule.
Reference
Medianfar CE et al. Cancer risk in patients with overall and site-specific lichen planus. JAMA Dermatol. 2026;DOI:10.1001/jamadermatol.2026.3933.
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