Did COVID-19 lockdown delay actually worsen melanoma prognosis?

BackgroundThe COVID-19 lockdown possibly meant a delay in the diagnosis and treatment of melanoma and therefore, worsening its prognosis. This unique situation of diagnosis deferral is an exceptional opportunity to investigate melanoma biology.ObjectivesTo evaluate the immediate and mid-term impact of diagnosis delay on melanoma.MethodsA retrospective observational study of melanoma diagnosed between March 14^th 2019 and March 13^th 2021. We compared the characteristics of melanomas diagnosed during the first 6-month period after the lockdown instauration and a second period after recovery of normal activity with the same periods of the previous year, respectively.ResultsA total of 119 melanomas were diagnosed. There were no differences in age, sex, incidence, location, presence of ulceration or mitoses, and in situ/invasive melanoma rate (p > 0.05). After the recovery of the normal activity, Breslow thickness increased in comparison with the previous year (2.4 vs 1.9 mm, p < 0.05) resulting in a significant upstaging according to the AJCC 8^th ed. (p < 0.05).Study limitationsThe main limitation is that this is a single-center study.ConclusionsThe COVID-19 lockdown implied a diagnosis delay leading to a mid-term increase in Breslow thickness and an upstaging of invasive melanomas. However, the detection deferral did not result in a higher progression of in situ to invasive melanoma, in our sample.