Impact of COVID-19 Pandemic on Delay of Melanoma Diagnosis: A Systematic Review and Meta-Analysis

Abstract

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.

Figure 1

Flow-chart of the selection process for the studies included in the literature review and meta-analysis.

Figure 2

Forest plot for the association between the occurrence of (A) invasive melanoma (vs. in situ, taken as reference) and (B) ulceration (vs. the absence of ulceration) with the diagnosis of melanoma in the post-lockdown period. (A) I² = 74.45, Begg p = 0.38, Egger p = 0.47; (B) I² = 78.39, Begg p = 0.29, Egger p = 0.014.

Figure 3

Forest plot for the association of high Breslow thickness with the diagnosis of melanoma in the post-lockdown period. (A) Breslow 1–2 mm vs. Breslow < 1 mm, I² = 0%, Begg p = 1.0, Egger p = 0.95; (B) Breslow > 2 mm vs. Breslow < 1 mm I² = 56.3%, Begg p = 0.48, Egger p = 0.18.

Figure 4

Forest plot for the association of melanoma AJCC stage and the diagnosis in the post-lockdown period. (A) Stage II vs. Stage I, I²:11.94%, Begg p = 0.87, Egger p = 0.92; (B) Stage III and vs. Stage I, I²:57.92%, Begg p = 0.04, Egger p = 0.002; (C) Stage IV vs. stage I, I²:4.81%, Begg p = 1.0, Egger p = 0.17.