1123P - Melanoma incidence and mortality decline in younger adults in Sweden: Start of a shift in the upgoing trend?

Background

Over the past decades, many regions have experienced a steady increase in the incidence of cutaneous melanoma. In recent years a downward trend has been observed in younger age groups in Australia and USA. Yet, in none of the European countries a significant decline in the melanoma incidence has been reported, in any age group. Here we explore melanoma incidence and mortality trends in Sweden, focusing on individuals younger than the average age of onset for melanoma.

Methods

This study is based on the national population based Swedish Melanoma Registry, covering >99% of all invasive melanomas diagnosed in the country, including 87 930 registered cases. Incidence and mortality rates per 100,000 inhabitants were calculated, in 1990-2022. Joinpoint regression models were used to evaluate statistical significance of temporal trends and points of change.

Results

In the years 1990-2022, 33 415 cases of invasive melanoma were diagnosed among patients under the age of 60 years (ys), with the following numbers of cases in each age group, 0-12ys (n=13), 13-19ys (n=243), 20-29ys (n=2 292), 30-39ys (n=5 709), 40-49ys (n=10 498) and 50-59ys (n=14 660). Throughout the study period, a constant melanoma incidence rise was observed in those ≥50ys. In the age groups 20-29, 30-39 and 40-49ys, there was a consistent incidence peak in the years 2014-2015 in both males and females, with a significant decline or leveling off in the period until 2022. In those <20ys the melanoma incidence remained low with no significant trends. During the study period, there was also a significant decline in the melanoma mortality in those aged 20-59ys but not in those ≥60ys.

Conclusions

This is the first report from a European country demonstrating a significant downward trend in the melanoma incidence and mortality among young adults. National campaigns that were initiated in the 1990s, promoting skin-cancer awareness and UV protection, emphasizing the importance of protecting children are likely contributory. Other factors may be a reduced usage of tanning devices, more hours spent indoor, together with an immigration of populations with darker skin. More effective oncological treatments are also likely promoting a decline in the population mortality of melanoma among young people.

Clinical trial identification

Editorial acknowledgement

Legal entity responsible for the study

Karolinska Comprehensive Cancer Center.

Funding

Cancerfonden, Radiumhemmets forskningsfonder.

Disclosure

H. Helgadottir: Financial Interests, Personal, Invited Speaker: Pierre Fabre, MSD, BMS. All other authors have declared no conflicts of interest.