The incidence of skin melanoma in Gran Canaria (Canary Islands, Spain) is lower than expected in Southern Europe despite high-risk environmental conditions: an island-wide cross-sectional study

[Translated article] Epidemiology of Primary Cutaneous Melanoma in the Migjorn Health Sector of Mallorca, Spain From 2003 Through 2021

The study of the increasing incidence of melanoma over the past few decades is essential regarding prevention and optimization of health resources. We collected cases of melanoma from Hospital son Llàtzer from the Migjorn health sector of Mallorca, Spain from 2003 through 2021, and calculated the incidence of melanoma adjusted to the standard European population. In addition, other demographic and clinicopathological data were descriptively analyzed too. A total of 690 new cases of melanoma were detected with a progressive increase in the age-standardized incidence from 7.47 cases per 100,000 inhabitants/year in 2003 up to 23.84 in 2021 mainly due to early stages of the disease. The incidence of melanoma has increased significantly in Mallorca probably due to the increasing population coming from northern Europe (low phototypes), sun exposure habits (tourism, fishing, agriculture), and improved early diagnosis.

Epidemiology of Primary Cutaneous Melanoma in the Migjorn Health Sector of Mallorca, Spain From 2003 Through 2021

The study of the increasing incidence of melanoma over the past few decades is essential regarding prevention and optimization of health resources. We collected cases of melanoma from Hospital son Llàtzer from the Migjorn health sector of Mallorca, Spain from 2003 through 2021, and calculated the incidence of melanoma adjusted to the standard European population. In addition, other demographic and clinicopathological data were descriptively analyzed too. A total of 690 new cases of melanoma were detected with a progressive increase in the age-standardized incidence from 7.47 cases per 100,000 inhabitants/year in 2003 up to 23.84 in 2021 mainly due to early stages of the disease. The incidence of melanoma has increased significantly in Mallorca probably due to the increasing population coming from northern Europe (low phototypes), sun exposure habits (tourism, fishing, agriculture), and improved early diagnosis.

Assessing the effect of environmental and socio-economic factors on skin melanoma incidence: an island-wide spatial study in Gran Canaria (Spain), 2007-2018

INTRODUCTION

Skin melanoma incidence has risen in the last decades becoming a major public health problem in many regions of the world. Geographic variation of rates is not well understood.

PURPOSE

To assess the spatial distribution of skin melanoma in Gran Canaria Island (Canary Islands, Spain) and to evaluate the role of environmental, socio-economic, and demographic factors in this distribution.

METHODS

We performed a small-area study with disease mapping at the census-tract level (CT) in Gran Canaria between 2007 and 2018. After testing for spatial autocorrelation, we integrated individual-level health data with census-based demographic and socio-economic indicators, and satellite-based environmental data. Finally, we assessed the role of demographic, socio-economic and environmental factors on skin melanoma incidence using a Bayesian analytical framework, with options for non-spatial and spatial random effects.

RESULTS

1058 patients were diagnosed with invasive skin melanoma in the study period and geolocated to a CT (number of CT in Gran Canaria = 565). We found evidence of global spatial autocorrelation in skin melanoma incidence (Moran's I = 0.09, pseudo p-value = 0.001). A few hotspots were detected, fundamentally in urban northern tracts. A radial pattern of high values was also observed in selected ravines with historical isolation. Multivariable conditional autoregressive models identified urbanicity, percent of females, and a high socio-economic status as risk factors for disease. Solar radiation did not show a significant role.

CONCLUSION

Urbanicity and a high socio-economic status were identified as the main risk factors for skin melanoma. These associations might reflect differential melanoma susceptibilities or be explained by health inequalities in detection. This study also uncovered high-risk areas in particular ravines. Future targeted research in these regions might help better understand the role of genetic and toxic factors in melanoma pathogenesis.