Rising cSCC and CIS Incidence in Denmark: Registry Findings (2005–2023)

A nationwide Danish registry report spanning 2005–2023 described rising incidence of invasive cutaneous squamous cell carcinoma (cSCC) and cSCC in situ (CIS), alongside shifting patterns across keratinocyte neoplasms.

These findings come from long-term trend data from routine histopathology and cancer registration, emphasizing changes over time rather than short-interval variation. Differences are reported by sex, age group, and anatomic site, with keratoacanthoma (KA) presented separately from cSCC and CIS.

The report describes case capture from Danish pathology and cancer registries, identifying 109,787 histologically confirmed first-time diagnoses among 95,352 adults aged 20 years or older between 2005 and 2023 in a Danish registry analysis (2005–2023). For invasive cSCC, age-standardized incidence rates (ASIRs) were reported to increase in both sexes, with estimated annual percentage changes (EAPCs) of 2.6% in males and 3.1% in females, reaching ASIRs of 131.6 and 77.7 per 100,000 person-years, respectively, by 2023. CIS was reported to rise more sharply, with EAPCs of 6.4% in males and 5.8% in females, while KA incidence was described as declining over the study period. Alongside absolute diagnosis counts, the report highlights ASIRs as a standardized way to track change over time. CIS showed the steepest annual increases, while invasive cSCC rose more steadily.

Stratified patterns of “who and where” were also described beyond the overall incidence curves. The authors were reported to note male predominance for lesions on the face, scalp, and neck, while females were described as having comparatively higher lower-limb ASIRs. The report further states that trends for cSCC and KA appeared stable among individuals younger than 50 years, which the authors suggested may reflect early effects of prevention efforts. These site- and age-specific observations were presented as context for interpreting the overall rise in invasive cSCC and CIS. Overall, the report juxtaposed sex-linked anatomic distribution with relative stability in younger adults over the same period.

The authors noted that the reported patterns may be relevant to how future surveillance activity and clinical care demands are considered, particularly by sex, age, and anatomical site.

Key Takeaways:

• From 2005–2023, research reports rising ASIRs for invasive cSCC in both sexes, with CIS increasing faster on an annual percent basis than invasive disease.
• The authors describe sex- and site-specific patterning (head/neck predominance in males and higher lower-limb rates in females) and report stable cSCC and KA trends in people younger than 50 years.
• The authors note that stabilizing trends in individuals younger than 50 years may reflect early prevention efforts and that findings may influence future surveillance and clinical care planning.