RESEARCH LETTER
Melanoma Diagnosis in the Post-COVID-19 Era: Return to “Normality” only in 2023 in 2 German Skin Tumour Centers
Peter MROTZEK1,2, Silke C. HOFMANN1, Alexander KREUTER3, Sebastian APPELBAUM2, Ulrich WESSELMANN1, Ulrich Peter WEHRY3 and Galina BALAKIRSKI1*
1Center for Dermatology, Allergology and Dermatosurgery, Helios University Hospital Wuppertal, University of Witten/Herdecke, Wuppertal, 2Faculty of Health, University of Witten/Herdecke, Witten, and 3Department of Dermatology, Venereology and Allergology, Helios St. Elisabeth Hospital Oberhausen, University of Witten/Herdecke, Oberhausen, Germany. *E-mail: galina.balakirski@helios-gesundheit.de
Citation: Acta Derm Venereol 2025; 105: adv42863. DOI: https://doi.org/10.2340/actadv.v105.42863.
Copyright: 2025 © The Author(s). Published by MJS Publishing, on behalf of the Society for Publication of Acta Dermato-Venereologica. This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial 4.0 International License (https://creativecommons.org/licenses/by-nc/4.0/).
Submitted: Jan 5, 2025; Accepted after revision: Jan 10, 2025; Published: Feb 25, 2025.
Dear Editor,
Numerous reports concerning melanoma (MM) during the COVID-19 pandemic stated reduced numbers of new diagnoses and increased Breslow thickness during lockdown in different countries, e.g., the USA, France, and Italy (1–3). Moreover, the number of melanomas with less favourable prognostic parameters such as higher mitotic rate (≥ 2) and presence of ulcerations increased during the COVID-19 pandemic, as shown in large retrospective cohorts from Italy, Austria, Switzerland, and Germany (4). Our working group showed an increase in sentinel lymph node metastasis in both pandemic years 2020 and 2021 compared with 2019 in 2 German dermatological clinics as a possible result of a diagnostic delay (5). However, less is known about the development of the melanoma diagnosis in the post-COVID-19 era.
To investigate whether the clinical and pathological parameters of newly diagnosed melanomas in the post-pandemic years have returned to pre-pandemic levels, we conducted a data analysis of all melanoma cases diagnosed and surgically treated between 1 January 2022 and 31 December 2023 in 2 board-certified skin cancer centres in North Rhine-Westphalia (Wuppertal and Oberhausen) and compared it with the already reported data from the years 2019 (before the SARS-CoV-2 pandemic) and 2020/2021 (during the pandemic) (5). For all identified MM cases, the following parameters were analysed: patient’s age, tumour thickness, pT-stage, presence of ulcerations, tumour stage according to the American Joint Committee on Cancer (AJCC), and detection of tumour infiltration in the sentinel lymph node (SLN), if applicable. The project was approved by the responsible ethics committee of University Witten/Herdecke (application number S-235/2021).
For statistical analysis IBM SPSS Statistics (version 29.0, IBM Corp, Armonk, NY, USA) was used. Descriptive statistics of metric scaled data were given by mean and standard deviation (SD). Group comparisons were performed using ANOVA and t-test to compare the groups with each other. The distribution of categorical data was presented by absolute and relative frequencies and compared between groups using a χ2 test. All statistical hypothesis testing was two-tailed with a significance level of 0.05.
There was no reduction in the annual number of MM during the COVID-19 pandemic; moreover there was a substantial increase in MM diagnoses in 2022 and 2023, with the largest increase (of 31.5% compared with 2019) in 2022. Neither tumour thickness nor tumour stages (both pT stages and tumour stages according to AJCC 2017) showed a statistically significant difference between each other and compared separately with the data from 2019 (see Table I).
| Factor | Year | p-value | |||||
| 2019 | 2020 | 2021 | 2022 | 2023 | |||
| Tumour thickness, mm, mean±SD | 1.7 ± 2.3 | 1.5 ± 1.7 | 1.9 ± 3.4 | 1.5 ± 2.1 | 1.5 ± 2.0 | 0.182 | |
| Age, year, mean ± SD | 62.5 ± 16.5 | 61.7 ± 17.3 | 64.0 ± 15.8 | 66.5 ± 16.0* | 64.7 ± 16.1 | < 0.001* | |
| Number of newly diagnosed MM, n | 320 | 319 | 347 | 421 | 379 | ||
| Age ≤ 40, n (%) | 40 (12.5) | 40 (12.6) | 30 (8.6) | 36 (8.6)* | 30 (7.9) | 0.044* | |
| Age > 40 / ≤ 70, n (%) | 162 (50.6) | 159 (49.8) | 182 (52.5) | 190 (45.1)* | 200 (52.8) | ||
| Age > 70, n (%) | 118 (36.9) | 120 (37.6) | 135 (38.9) | 195 (46.3)* | 149 (39.3) | ||
| AJCC stage, n (%) | |||||||
| 0 (in situ) | 55 (17.2) | 41 (12.9) | 54 (15.5) | 83 (19.7) | 80 (21.1) | 0.51 | |
| I | 185 (57.8) | 196 (61.4) | 206 (59.4) | 241 (57.2) | 213 (56.2) | ||
| II | 55 (17.2) | 47 (14.7) | 50 (14.4) | 60 (14.3) | 55 (14.5) | ||
| III | 19 (5.9) | 29 (9.1) | 26 (7.5) | 36 (8.6) | 28 (7.4) | ||
| IV | 6 (1.9) | 6 (1.9) | 11 (3.2) | 1 (0.2) | 3 (0.8) | ||
| Tumour thickness, mm, n (%) | |||||||
| ≤ 1 | 147 (45.9) | 156 (48.9) | 163 (47.0) | 200 (47.5) | 169 (44.6) | 0.742 | |
| > 1–2 | 51 (15.9) | 61 (19.1) | 57 (16.4) | 69 (16.4) | 64 (16.9) | ||
| > 2–4 | 32 (10.0) | 36 (11.3) | 42 (12.1) | 38 (9.0) | 44 (11.6) | ||
| > 4 | 35 (10.9) | 25 (7.8) | 31 (9.0) | 31 (7.4) | 22 (5.8) | ||
| pT stage, n (%) | |||||||
| pT1 | 149 (46.6) | 155 (48.6) | 168 (48.4) | 197 (46.8) | 169 (44.6) | 0.198 | |
| pT2 | 47 (14.7) | 63 (19.7) | 55 (15.9) | 74 (17.6) | 63 (16.6) | ||
| pT3 | 34 (10.6) | 34 (10.7) | 40 (11.5) | 39 (9.3) | 45 (11.9) | ||
| pT4 | 35 (10.9) | 26 (8.1) | 30 (8.7) | 28 (6.6) | 22 (5.8) | ||
| Presence of ulcerations, n (%) | 53 (16.6) | 57 (17.9) | 67 (19.3) | 77 (18.3) | 61 (16.1) | ||
| Performed SLNB, n (%) | 106 (33.1) | 102 (32.0) | 110 (31.7) | 127 (30.2) | 120 (31.7) | 0.260 | |
| Positive SLNB, n (%) | 10 (9.4†) | 20 (19.6†)* | 20 (18.2†)* | 24 (18.9†)* | 21 (17.5†) | ||
| †Percentage of positive sentinel lymph nodes detected from the performed SLNB. *Statistically significant increase compared with the year 2019 (p < 0.5). |
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There was a statistically significant difference in the mean age of patients when using ANOVA. However, when the years were compared separately with the 2019 data using a t-test, there was only statistically significant higher patient age in 2022. Although there was similar proportion of young MM patients (≤ 40 years of age) compared with the year before the COVID-19 pandemic, it was a significantly higher proportion of older patients (˃ 70 years old) who presented with MM at the 2 participating clinics in 2022 (p = 0.021).
There was no statistical significance in the number of sentinel lymph node biopsies (SLNBs) performed in the years following the SARS-CoV-2 outbreak. However, the proportions of positive SLNBs were statistically significantly higher in 2020, 2021, and 2022 than in 2019 (Fig. 1). The year 2023 was the first year after the start of the COVID-19 pandemic in which the clinically distinct increase in positive SLNBs compared with 2019 (21 [17.5%] vs 10 [9.4%]) was no longer statistically significant.
Fig. 1. Presentation of positive sentinel lymph node biopsies (SLNBs) in the years 2019 to 2023 with corresponding statistical analysis of the respective years compared with 2019 using the chi-square test. A p-value < 0.05 was considered statistically significant (here shown in bold).
So far, less is known about melanoma development in the years following the COVID-19 pandemic. A retrospective cohort from Romania revealed that also in the year 2022 and at the beginning of 2023 (second post-pandemic year defined as the period from 1 March 2022 to 28 February 2023), Breslow thickness and mitotic rate of newly diagnosed melanomas were still significantly higher compared with the pre-COVID-19 period (6).
The exact cause of this development is unclear. One explanation for our results could be that COVID-19 restrictions in Germany were waived only gradually. In February 2023 the requirement to wear a surgical mask on public transport was removed. In April 2023 all remaining restriction measures were terminated, officially marking the end of the pandemic. However, although the epidemiological situation was stable during 2022 and 2023 and appointments with healthcare professionals and scheduled surgical procedures were possible without any restrictions, our data indicate no return to “normality” before 2023. The increase in MM patients over 70 years of age in 2022 may be a possible indication that this patient group, which was at highest risk in the COVID-19 pandemic, were finally daring to visit dermatologists again. In 2023 the age ratio returned to pre-COVID values again.
A diagnostic and therapeutic delay in patients with melanoma significantly worsen their prognosis, as the median tumour doubling time was estimated to be 94 days (7). Also, an empiric rate of growth model for MM suggested that about one-third of the lesions with a Breslow thickness of ≤ 1 mm would achieve tumour thickness of over 1 mm (or pT2 stage) after a diagnostic delay of 3 months (8). It is therefore possible that the normalization of epidemiological MM development started with a delay only in 2023.
ACKNOWLEDGEMENTS
The authors would like to thank Beate Balkes (Medical Documentation of the Philipp Klee-Institute for Clinical Pharmacology, Helios University Hospital Wuppertal) and Steffen Goldbach (Medical Documentation of the Department of Dermatology, Venereology and Allergology, Helios St. Elisabeth Hospital Oberhausen) for providing the clinical information on tumour diagnosis and thickness.
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