- Design
- Nationwide register-based retrospective cohort
- Population
- 35,845 Danish patients with incident lichen planus and no prior cancer
- Primary outcome
- Cancer incidence compared with the general population
- Effect
- Women: oral cavity SIR 7.5 (95% CI 6.4 to 8.9); vulva 2.6 (2.0 to 3.4); 20-year oral cavity risk 0.8%
A Danish nationwide register cohort followed 35,845 people with a new diagnosis of lichen planus from 1978 to 2020, all without previous cancer, and compared their cancer rates with the general population. Published in JAMA Dermatology on 14 October 2026.
In women, rates were raised for cancers of the lip (standardised incidence ratio 6.0, 95% CI 3.3 to 10.0), oral cavity (7.5, 6.4 to 8.9) and tongue (6.8, 5.4 to 8.4), and for vulval cancer (2.6, 2.0 to 3.4). Cutaneous squamous cell carcinoma was slightly raised (1.4). Men showed a similar pattern. Oral cancer risk was highest in people with oral lichen planus, and genital cancer risk in those with genital disease. The 20-year absolute risk of oral cavity cancer was 0.8% in women and 1.0% in men; of genital cancer, 0.4% and 0.2%.
This is observational, and some excess may reflect closer examination of people already under follow-up. But the site-specific pattern is consistent and supports a follow-up plan matched to where the disease is, rather than discharging patients once skin lesions settle. In India, where tobacco and areca nut use add to oral cancer risk, the case for oral review is stronger.
- Arrange periodic oral examination for patients with oral lichen planus, with dental or oral medicine input
- Arrange periodic genital review for patients with genital lichen planus
- Biopsy any non-healing ulcer, thickened plaque or changing area at an affected site
- Advise stopping tobacco and areca nut, which add to oral cancer risk
- Explain that absolute risk is low, around 1% over 20 years for oral cancer
Why it matters
Discharging a patient once skin lesions fade leaves mucosal disease, and its cancer risk, unwatched.
Don't overread it
This is an association from register data; it does not establish a follow-up interval or show that surveillance saves lives.
The statistics, in plain English
A standardised incidence ratio of 7.5 means about seven and a half times as many oral cavity cancers as expected in the general population. Because these cancers are rare, that still translates into an absolute 20-year risk of about 1 in 100.
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