Introduction: Several studies have described how the restrictive measures due to COVID-19 have delayed melanoma diagnoses, resulting in an increased rate of more severe cases. Summarizing the sparse results in this context might help to understand the real impact of the COVID-19 pandemic on melanoma. We conducted a systematic review and meta-analysis to investigate how the clinical and prognostic factors of new melanoma diagnoses changed after COVID-19.
Methods: A literature search in MEDLINE, EMBASE, and Scopus was conducted in September 2023. We included studies published in peer-reviewed journals reporting histopathological data on new diagnoses of cutaneous melanoma in adult patients during and/or after the lockdown compared to those diagnosed before the COVID-19 pandemic. A meta-analysis was conducted utilizing a random effects model. The between-study heterogeneity was assessed via Higgins's I2 statistic. Publication bias was assessed using the Begg and Egger test. This study adhered to the updated PRISMA guidelines. The primary outcome was a comparison of melanoma thickness between the pre-COVID-19 and post-lockdown periods. The secondary outcomes were evaluations of the histopathological subtype, stage, and presence of ulceration and mitosis in melanomas diagnosed in these two pandemic phases.
Results: The study included 45 articles. We found a significantly higher proportion of all factors indicating worse prognosis in the post-lockdown period compared to the pre-COVID-19 phase, including high thickness (SOR = 1.14, 95%CI 1.08-1.20 for 1-2 mm; SOR = 1.62, 95%CI 1.08-2.40, for >2 mm), the presence of ulcerations (SOR = 1.35, 95%CI 1.18-1.54), nodular subtype (SOR = 1.19, 95%CI 1.07-1.32), the presence of mitosis (SOR = 1.57, 95% CI 1.17-2.11), and stage III (SOR = 1.39, 95%CI 1.19-1.52) and IV (SOR = 1.44, 95%CI 1.26-1.63). Limitations include the limited studies' geographical distribution and moderate heterogeneity affecting meta-analysis estimates.
Conclusions: Our meta-analysis provided evidence of more advanced melanomas diagnosed in the post-COVID-19 pandemic period, emphasizing the importance of creating and updating pandemic preparedness plans to limit the impact of any future events on oncological care.
Keywords: COVID-19; diagnostic delay; melanoma; prognosis.