Cutaneous melanoma in Argentina: an analysis of its characteristics and regional differences.

Purpose: This study aims to increase the knowledge about the characteristics of cutaneous melanoma in Argentina, their association with the risk of having Breslow ≥1 mm and mortality trends for the period 2002-2017.

Patients And Methods: Descriptive statistics and regression analyses were done for 10.199 cases within the Argentine Melanoma Registry in the period 2002-2018. Trends in age-standardised mortality rates (ASMR) were analysed using the Join point Regression Model.

Results: Cases showed lesions mainly located in males' trunk (37%) and in females' lower limbs (29%). The level of invasion was higher in males who also showed higher mortality. Cases from the North West and North East regions showed a major risk of Breslow >1 mm and harboured CM in lower limbs more frequently than in other regions. Nearly, 25% of tumours over 2 mm were in cases aged <50 years and 37.6% in patients ≥50 years. In the North West, North East and Patagonia, the frequency of cases in young people was higher than in older people. In 43% of cases, the melanoma subtype was not specified in the report. The number of superficial spreading melanomas, the most common histology, was nearly twice that of Nodular melanomas the following histology in importance (3,403 and 1,754, respectively). Melanoma mortality rates in all Argentine population increased in the elderly. Lower melanoma mortality rates were observed in the North West. In 2007-2017, ASMR decreased significantly in females (average 1.4% p/year) while it increased nonsignificantly in males (0.4% p/year).The tumours with the worst prognosis were associated with the elderly, males, nodular or acrolentiginous morphologies, residing somewhere other than Centro and Patagonia and with tumors located in the head/neck and legs.

Conclusion: The geographical variations found for melanoma characteristics and their mortality in Argentina, makes it imperative that epidemiological research is continued to avoid generalisations and improve future preventive actions.