Data from this new study suggest melanoma cases rose at a slower rate in lower-income countries, but the authors say that may be due to differences in case documentation.
Cases of melanoma increased slightly in the United States over the past 3 decades, according to a new analysis, but the data suggest the patients most affected by upward melanoma trends are those older than 60 years.
The team of investigators analyzed data from the Global Burden of Disease Study 2017 to see what they said about trends in melanoma prevalence and outcome, and they published their results in ePlasty.
They noted that recent decades have seen significant shifts in public awareness about melanoma, and in the diagnosis and care of the skin cancer, and that because of this it is important to examine how these interventions have affected rates and outcomes in melanoma. The research will also set a new baseline against which to judge future mitigation efforts, they added.
The Global Burden of Disease Study includes data related to more than 350 diseases and injuries in 195 countries. The investigators culled data from 1990 to 2017 related to melanoma incidence, mortality, and disability-adjusted life-years (DALYs).
Overall, incidence of melanoma increased 1.6 times in the United States over the study period, from a rate of 10.95 to 17.54 cases per 100,000 people. That increase, however, did not reach statistical significance, the authors said. When the investigators compared these results to other countries grouped by sociodemographic index (SDI) rankings, they found similar growth. Middle-income countries had the highest rate ratio of 1.72, and low-income countries had the lowest growth, at 1.05.
However, among people in the United States over the age of 60, the increases in incidence were statistically significant, particularly for the oldest Americans. For patients aged 60 to 64 years, the incidence rate increased from 28.22 to 48.6 cases per 100,000, and for patients older than 95 years, the rate jumped from 50.34 to 133.2 cases per 100,000.
A similar trend was found for mortality. Overall, the mortality rate among Americans was unchanged: from 2.07 cases per 100,000 in 1990 to 2.06 cases in 2017, for a rate ratio of 0.99. In many age groups, mortality declined. Globally, mortality rates were similarly stable. However, for people in the United States over the age of 65, mortality increased. For people ages 75 to 79, for instance, the melanoma mortality rate was 11.35 deaths per 100,000 people in 1990 and 14.29 deaths per 100,000 people in 2017. As with incidence, the highest increases were for the oldest patient groups.
In terms of mortality to incidence ratio, the rate decreased in the United States, but the change did not reach statistical significance, the authors said. DALYs decreased slightly overall, but increased significantly for patients over the age of 75.
The authors wrote that the overall increase in incidence might be due in part to increased awareness of the disease and better access to screening.
Their comparison of countries based on SDI scores suggested that rates were increasing faster in higher-income countries than in lower-income countries. However, the authors said this may not be what it appears. They said it may be that higher-SDI countries appear to have higher rates of melanoma due to improved case documentation.
“In addition, increased life expectancy in higher-SDI countries and decreased mortality related to other common causes of death in lower-SDI countries (eg, injuries, labor-related conditions, cardiovascular events) may also be related to this ‘falsely’ elevated mortality related to melanoma in higher-SDI countries,” they wrote.
The authors suggested that, with new immunotherapy and targeted chemotherapy options developed in the early 2010s, it is likely that melanoma mortality will decline notably in the coming years.
Siotos C, Grunvald MW, Damoulakis G, et al. Trends in skin melanoma burden: findings from the Global Burden of Disease Study. Eplasty. Published online April 12, 2022.