Incidence and Survival of Cutaneous Squamous Cell Carcinoma: A Spanish Multicenter Population-Based Study

Cutaneous squamous cell carcinoma (cSCC) constitutes a serious public health problem, as it is the 2nd most frequent skin cancer. Few studies have assessed epidemiological indicators of cSCC in Southern Europe. The objectives of this study were to analyze its incidence rate and estimate survival of cSCC cases from all Spanish population-based cancer registries that register this cancer.

We conducted a retrospective descriptive study of all incident first cSCC cases registered in Girona, Granada, Navarre and Tarragona (Spain) from 1994 to 2017. Crude and age-standardized (ASR-E) incidence rates were calculated. Incidence trends were analyzed using joinpoint regression. Observed survival was estimated using the Kaplan-Meier method and relative survival was estimated using the Ederer II method.

A total of 22,434 cSCC cases (61.5% men) were registered, accounting for 20.3% of all skin cancers. The most common anatomical site was the skin of face, scalp and neck (59.1%) and the incidence rate increased exponentially with age. The annual ASR-E per 100,000 inhabitants was 25.0 in women and 56.6 in men. Both sexes showed a significant upward incidence trend, with an annual percent change of +2.0% (95%CI, +1.6% to +2.4%). The 5-year relative survival rate was 93.5% (95%CI, 92.5-94.6%), slightly higher in women, and did not seem to increase over time.

This study provides an updated description of cSCC incidence and survival, which are key indicators to frame the scenario of this cancer in Spain. Overall, results are consistent with former studies, showing a rising trend in the incidence rate alongside high survival rates. Further research is warranted to elucidate the causes underlying these findings.