Impact of UV Exposure and Incidence of Merkel Cell Carcinoma Between 1990 and 2018 in Austria

Background: The purpose of this study was to report on (i) patients’ demographics and (ii) Austrian UV data, and (iii) to examine a possible association between UV exposure and the onset of disease in Austria between 1990 and 2018. Methods: We included all patients diagnosed with MCC and their clinical and demographic data to compare with UV radiation. Results: A total of 538 cases were identified, and the incidence (per 100.000/y) increased from 0.013 to 0.43. The MCC incidence was significantly higher in West Austria (mean incidence 0.269 ± 0.04) compared to East Austria (0.180 ± 0.02 p = 0.005). Notably, the mean and maximum UV radiation values were higher in the western (p < 0.001) compared to the eastern part of Austria. The sum (p = 0.033; r: 0.503) and mean (p = 0.019; r: 0.546) UV values correlated significantly with the MCC incidence. Conclusions: The incidence of MCC increased significantly, and higher UV radiation levels in western Austria compared to the east were associated with a correspondingly higher MCC incidence, suggesting a contributing role of UV radiation in general.