Impact of the Covid‐19 pandemic on melanoma diagnosis: A retrospective study from the French clinical database of melanoma patients (RIC‐Mel)

Impact of the Covid-19 pandemic on melanoma at initial diagnosis was not unanimously appreciated. Most studies, evaluating only pathologic criteria of melanoma, showed in postlockdown period increased thickness, less stage 0 and more stage II.1 However, a large study (20.434 patients) found minimal impact of the Covid-19 pandemic on melanoma thickness.2 Impact on metastatic diseases, evaluated in smaller studies, showed increased stage III, and increased or no change for stage IV.3, 4 To analyze the impact of the Covid-19 pandemic, we compared newly diagnosed melanomas recorded in the French national multicentric database RICMEL between the 1-year prelockdown period (pre-LD, March 17, 2019, to March 16, 2020) and the 1-year postlockdown period (post-LD, May 11, 2020, to May 10, 2021). A total of 2137 patients were included from 28 centers, representative of the different French regions, 1119 in pre-LD and 1018 in post-LD (Table 1). Demographics features were similar between the two periods. In post-LD versus pre-LD, melanomas were less thin (<1 mm) (307/34.1% vs. 363/37.7% respectively) and more ulcerated (259/25.4% vs. 250/22.3%, respectively). However, thickness and ulceration showed no significant difference in pre- and postlockdown periods. Stages' distribution was significantly different (p = 0.031). In post-LD, stage 0 decreased (118/11.6% vs. 156/13.9%), stage II (249/24.5% vs. 249/22.2%), and stage III (152/14.9% vs. 131/11.7%) increased; and stage IV (38/3.7% vs. 59/5.3%) decreased. In details, the most important increases in post-LD concerned stage IIC (74/7.3% vs. 64/5.7%) and stage IIIC (90/8.8% vs. 72/6.4%) (Table 2). Melanoma subtypes showed less lentigo melanoma/lentigo malignant melanoma (LM/LMM) subtype (71/7% vs. 100/8.9%) in post-LD. Sentinel lymph node (SLN) biopsy was more frequent in post-LD (380/37.3% vs. 321/28.7%, p < 0.000). During the Covid-19 pandemic, routine consultations for screening were frequently canceled. This could explain less in situ and stage I melanoma in post-LD as these melanomas were frequently asymptomatic. In this line LM/LMM, frequently diagnosed with a thin Breslow or in situ, were also decreased in post-LD. Our results revealed an impact of the COVID-19 pandemic on melanoma severity at initial presentation. Indeed, we observed a trend for more aggressive, that is, thicker and ulcerated, primary melanomas in post-LD. These results were not significant possibly due to too small effectives and missing data. However, they were supported by the modification in stages' distribution. Indeed, we observed more stage II and III in post-LD. Related to this, more sentinel biopsy procedures were performed in post-LD with the same positivity rate, suggesting no modification of practices. The increased stage III in post-LD could be explained by the clinical delay with macrometastasis and more frequent SLN biopsies performed. This distribution of metastatic melanomas in post-LD (more stage III and less stage IV) may represent the natural history of melanoma which spreads preferentially in lymph nodes before visceral metastasis. The more aggressive subgroups (stage IIC and stage IIIC) were increased in post-LD although, due to the small size of each subgroups, these results were not significant. Our study did not support a role of demographical characteristics (age, sex) to explain the observed modifications in post-LD. This may be mostly due to delays in medical care, secondary to disorganization of medical staff, patient fear of getting covid-19 infection in hospital and psychologic distress inducing depression.5 In conclusion, the present study showed a negative impact of the COVID-19 pandemic with more stages II and III in post-LD at initial diagnosis of melanomas. François Skowron, Stéphane Mouret, and Marie-Thérèse Leccia: study design, data collection, interpretation of results, manuscript preparation, approval of final manuscript. Arnaud Seigneurin: statistical analysis of results, manuscript preparation, approval of final manuscript. Henri Montaudié, Eve Maubec, Florent Grange, Gaelle Quereux, Philippe Célérier, Mona Amini-Adle, Sophie Dalac-Rat, Julie De Quatrebarbes, Ouidad Zehou, Abed Safia, Philippe Muller, Philippe Modiano, Laurent Misery, Noemie Litrowski, Florence Brunet-Possenti, Laurent Mortier, Guido Bens, Alice Hervieu, Nicolas Leduc, Thomas Jouary, Candice Lesage, Nathalie Beneton, Yannick Le Corre, Lionnel Geoffrois, Domitille Thomas-Beaulieu, and Ewa Hainaut: Data collection. The authors have no funding to report. The authors declare no conflict of interest. The RicMel database (Clinical Trials n°. NCT03315468) gathers data from 49 participating centers in different French regions. It received ethics committee approval on February 9, 2012 (no. 12.108) from the Independent Ethics Committee of Paris and authorization from the French Data Protection Agency (CNIL, DR-2012—259, May 28, 2012). All patients in this manuscript have given written informed consent for participation in the study and the use of their deidentified, anonymized, aggregated data and their case details for publication. The data that support the findings of this study are available from the corresponding author upon reasonable request.