Long-lasting effects of the COVID-19 pandemic on the incidence and depth of malignant melanoma

The COVID-19 pandemic has influenced healthcare systems worldwide, which is also evident in the treatment of -malignant melanoma. In this study, the effects of the pandemic on the incidence and depth of invasion of malignant melanoma of the skin were investigated. We retrospectively investigated the incidence as well as the average tumour thickness during the course of the pandemic and the pre-pandemic year. Data from the Department of Dermatology at Hietzing Hospital, Vienna, were analysed. Average depth of invasion of malignant melanomas was measured by Breslow index (BI), and the total number of patients with diagnosed malignant melanomas that were excised was analysed. A significant reduction in excisions (pcorr.=0.007) was found based on comparison between the pre-COVID-19 cohort (227 subjects) and the cohort of the second year of the pandemic (136 subjects). The average BI was 1.1±1.14 mm in the pre-COVID-19 cohort, and 1.8 ± 2.3 mm in the first and 1.4±1.85 mm in the second-pandemic-year cohort. A significant difference in average tumour thickness was detected between the pre-COVID-19 and the first-pandemic-year cohort (pcorr. =0.003), as well as between the pre-COVID-19 and the second-pandemic-year cohort (pcorr.=0.027). The long-lasting effects of the pandemic are discussed based on the further decline in the number of excisions and a simultaneous increase in the average BI during the second year of the pandemic.