Impact of the COVID-19 pandemic on the care of patients with malignant melanoma Dear Editors, the COVID-19 pandemic led to numerous limitations in medical care. In patients with malignant melanoma, early detection is critical for prognosis.To clarify whether the pandemic had an impact on tumor thickness at initial diagnosis, we conducted a survey of melanoma patients undergoing sentinel lymphonodectomies at 105 German dermatology clinics. We thereby considered January 2021 (during the lockdown) as well as corresponding periods before the pandemic in January 2020 and January 2019.The query included age, sex, tumor thickness, ulceration, and TNM stage (according to AJCC 2017). Tumor thickness at initial diagnosis in January 2021 was compared with corresponding values from the two previous years using a t-test. Due to the right-skewed distribution of tumor thickness, the data were first transformed (logarithmized). The significance level of 5% was adjusted after Bonferroni correction, with a P value < 0.025 assumed to be statistically significant. The survey was approved by the Ethics Committee of the Hannover Medical School (No. 9570_BO_K_2021).Forty-nine dermatology hospitals reported complete data sets. The total sum of all sentinel lymph node surgeries was