key: cord-344273-uztk6pc0
authors: Tejera‐Vaquerizo, Antonio; Nagore, Eduardo
title: Estimated effect of COVID‐19 lockdown on melanoma thickness and prognosis: a rate of growth model
date: 2020-05-02
journal: J Eur Acad Dermatol Venereol
DOI: 10.1111/jdv.16555
sha: 
doc_id: 344273
cord_uid: uztk6pc0

The coronavirus COVID‐19 pandemic, which emerged in Wuhan, China several months ago,(1) has led to large‐scale lockdown in many countries around the world, including Spain. Uncertainty about the duration of these measures led us to consider the potential impact of diagnostic delays due to the paralyzation of certain health procedures and services on the prognosis of patients with melanoma.

To de Editor,

The coronavirus COVID-19 pandemic, which emerged in Wuhan, China several months ago, 1 has led to large-scale lockdown in many countries around the world, including Spain. Uncertainty about the duration of these measures led us to consider the potential impact of diagnostic delays due to the paralyzation of certain health procedures and services on the prognosis of patients with melanoma.

To estimate this impact, we built a model based on melanoma rate of growth (ROG). 2 ROG is the rate of increase in Breslow thickness, as a surrogate measure for tumor volume, from the time a patient first notices a lesion or observes changes in an existing lesion, to excision of the tumor. It is measured as millimeters per month (Fig. 1) . Although ROG in our model was based on subjective information provided by the patient, it has been found to match ROG values calculated using biopsy specimens taken from the same lesions at different moments of time. 3 Melanoma ROG has been associated with prognosis 4,5 and a higher probability of lymph node involvement. 6 We randomly selected 1000 melanomas with a known ROG from the database of Instituto Valenciano de Oncología in Valencia, Spain. The tumors were classified according to thickness (T1, T2, T3, or T4) based on the melanoma staging criteria of the American Joint Committee on Cancer (AJCC). 7 For each case, we used ROG to estimate tumor thickness after a diagnostic delay of 1, 2, and 3 months. We calculated, for example, that a melanoma with a Breslow thickness of 2 mm at diagnosis and a ROG of 0.5 mm a month would measure 2.5 mm after 1 month, 3 mm after 2 months, and 3.5 mm after 3 months. Using AJCC survival data for the different T stages, 7 we then calculated 5-and 10-year survival rates for the patients divided into diagnostic groups (initial sample and the same group at the three time points analyzed).

Over half of the melanomas in the initial sample (n=403; 40.3%) were T1. Of the remaining tumors, 24.2% were T2, 19.2% were T3, and 16.3% were T4. For patients in the 1-month diagnostic delay group, the model predicted an upstaging rate of 21% (i.e., progression to the next tumor stage in 21% of cases). The proportion of tumors that would be upstaged in the other two groups was 29% in the 2-month-delay group and 45% in the 3-month-delay group ( Estimated 5-year survival for the group as a whole was 94.2% in the initial sample and 92.3% in the group of patients whose diagnosis was delayed by 3 months. The respective 10-year survival rates were 90% and 87.6%.

One limitation of our study is that the random sample included 1000 cases, although the distribution of tumor thickness measurements was very similar to that in the Spanish National Melanoma Registry. 8 We did not estimate clinical progression rates, as it was impossible to estimate the proportion of nonulcerated tumors that would become ulcerated in the time periods considered. The actual differences in survival rates could thus be even greater.

Our ROG model shows that in the absence of adequate care for cancer patients in the current lockdown situation in Spain, our healthcare system could see a considerable rise in melanoma upstaging cases, and, of course, healthcare costs. 9 Approximately 300 patients are diagnosed of cutaneous melanoma every month in Spain, 10 and if we extrapolate this figure to countries with similar lockdown measures, many of which have a higher incidence of melanoma, it would not be unrealistic to predict a situation with potentially serious consequences. In conclusion, considering the current situation, efforts should be made to promote self-Accepted Article examination and facilitate controlled access to dermatologists (through teledermatology, for example), as this will prevent delays resulting in worse prognosis. 

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