Cutaneous squamous cell carcinoma 1986–2019 in Germany: Incidence, anatomical site, staging, and histologic subtypes

BACKGROUND: Cutaneous squamous cell carcinoma (cSCC) is the second most common non-melanoma skin cancer. Population-based data analysis in Germany has largely focused on incidence. Recently analysed datasets covered 4,75 % of the population. OBJECTIVES: To assess incidence, anatomical site- and T-stage distribution, histological subtypes of cSCC in Germany, with a focus on sex- and age-group specific patterns and regional differences. MATERIALS AND METHODS: 213,935 first primary cSCC cases diagnosed between 1986 and 2019 from four federal states of Germany with complete case ascertainment were analysed. The dataset covers ∼35 % of the German population. Crude- and age-standardised incidence rates (CIR, ASIR) were calculated, and subgroup analyses were performed by sex, anatomical site, histological subtype, T-stage and region. RESULTS: CIR increased by > 500 % from 1986 to 2015, with a steeper rise in women. Incidence plateaued after 2015, except for a delayed increase in Saarland. Facial tumours were most frequent, with equal incidence in males and females. T1 tumours predominated (88.6 %), although staging data were incomplete in 33.5 % of cases. Regional and sex-based differences were observed in both T-stage and histological subtypes. Spindle cell and non-keratinising variants were associated with more advanced stages. Cancer registry data did not count more than one cSCC and carcinoma in situ such as actinic keratosis, leading to systematic underestimation of disease burden. CONCLUSIONS: cSCC incidence has risen substantially in Germany, with significant variation by sex, region, and tumour type. Improved registry protocols incorporating multiple primaries, clinical staging, and early in situ lesions are essential for accurate surveillance and healthcare planning.