Stage-specific incidence trends of melanoma in an English region, 1996-2015: longitudinal analyses of population-based data.

Abstract

The aim of this study was to examine temporal trends in overall and stage-specific incidence of melanoma. Using population-based data on patients diagnosed with melanoma in East Anglia, England, 1996-2015, we estimated age-standardized time trends in annual incidence rates for each stage at diagnosis. Negative binomial regression was used to model trends over time adjusted for sex, age group and deprivation, and to subsequently examine variation in stage-specific trends by sex and age group. The age-standardized incidence increased from 14 to 29 cases/100 000 persons (i.e. 4% annually). Increasing incidence was apparent across all stages but was steepest for stage I [adjusted annual increase: 5%, 95% confidence interval (CI): 5-6%, and more gradual for stage II-IV disease (stage II: 3%, 95% CI: 2-4%; stage III/IV: 2%, 95% CI: 1-3%)]. Stage II-IV increase was apparent in men across age groups and in women aged 50 years or older. Increases in incidence were steeper in those aged 70 years or older, and in men. The findings suggest that both a genuine increase in the incidence of consequential illness and a degree of overdiagnosis may be responsible for the observed increasing incidence trends in melanoma in our population during the study period. They also suggest the potentially lower effectiveness of public health awareness campaigns in men and older people.