Trends in Melanoma Incidence Rates in Eight Susceptible Populations through 2015

Abstract

Melanoma incidence and mortality rates continue to rise globally (Erdmann et al., 2013Erdmann F. Lortet-Tieulent J. Schuz J. Zeeb H. Greinert R. Breitbart E.W. et al.International trends in the incidence of malignant melanoma 1953–2008—are recent generations at higher or lower risk?.Int J Cancer. 2013; 132: 385-400Crossref PubMed Scopus (466) Google Scholar). Although public health campaigns aimed at reducing sun exposure and use of sunbeds have been launched by many health agencies, the breadth and duration of such campaigns varies significantly across countries. In 2016, we published data on melanoma incidence trends through 2011 in six susceptible populations with different histories of sun protection campaigns (US Whites, United Kingdom, Sweden, Norway, Australia, and New Zealand) and projected trends out to 2031 (Whiteman et al., 2016Whiteman D.C. Green A.C. Olsen C.M. The growing burden of invasive melanoma: projections of incidence rates and numbers of new cases in six susceptible populations through 2031.J Invest Dermatol. 2016; 136: 1161-1171Abstract Full Text Full Text PDF PubMed Scopus (345) Google Scholar). Our models predicted that annual increases in melanoma incidence of approximately 3% in the United Kingdom, Sweden, Norway, and US whites would be sustained until 2031 and that rates in Australia and possibly New Zealand were expected to decline. We postulated that these observed differences across countries were mainly due to differences in investments in sun protection campaigns and sunbed regulations, although other secular trends, including migration-dilution effects (Czarnecki, 2014Czarnecki D. The incidence of melanoma is increasing in the susceptible young Australian population.Acta Derm Venereol. 2014; 94: 539-541Crossref PubMed Scopus (20) Google Scholar), may contribute (Baade et al., 2015Baade P.D. Youlden D.R. Youl P. Kimlin M. Sinclair C. Aitken J. Assessment of the effect of migration on melanoma incidence trends in Australia between 1982 and 2010 among people under 30.Acta Derm Venereol. 2015; 95: 118-120Crossref PubMed Scopus (12) Google Scholar). We have now updated our analyses of invasive melanoma incidence trends in these six populations by adding the most recent 4 years of data (i.e., 2012–2015, inclusive). We have also examined incidence trends for the entire period of 1982–2015 in two other populations with moderate to high melanoma incidence, Denmark and Canada. We obtained data on incident invasive melanoma cases from population-based cancer registries in the United States, the United Kingdom, Norway, Sweden, Denmark, and New Zealand from 1982 through 2015 (see Supplementary Materials online). Incidence data were unavailable for Australia for the year 2015 and for Canada (except Quebec) before 1992. We calculated the average annual percentage rate change in invasive melanoma incidence using the Joinpoint Regression Program, version 4.0.4 (National Cancer Institute, Rockville MD) using the Hudson continuous fitting algorithm (Hudson, 1966Hudson D.J. Fitting segmented curves whose join points have to be estimated.J Am Stat Assoc. 1966; 61: 1097-1129Crossref Scopus (306) Google Scholar). All incidence rates were standardized to the US 2000 population as the reference population most similar to the demographic distribution of the high income countries studied, therefore ensuring that the age-specific rates in elderly populations are weighted appropriately. In the most recent year of data, the age-standardized incidence rates for invasive melanoma were highest for Australia (50.3/100,000) and New Zealand (47.4/100,000), followed by Denmark (33.9/100,000), Norway (32.7/100,000), US whites (32.4/100,000), and Sweden (29.3/100,000). Rates were substantially lower in the United Kingdom (20.0/100,000) and Canada (17.9/100,000). Recent trends in melanoma incidence varied across populations (Figures 1 and 2). In US whites, the United Kingdom, Sweden, and Norway, incidence continued to increase at a rate of 1.7% (95% confidence interval [CI] = 1.2–2.2), 2.7% (95% CI = 2.0–3.5), 4.8% (95% CI = 4.0–5.6), and 4.5% per year (95% CI = 3.8–5.2), respectively. For Canada (except Quebec), incidence increased steadily since 1992 at a rate of 1.9% per year (95% CI = 1.7–2.0). Although our earlier analysis suggested that rates in Australia might have been declining, the additional data points for 2012 through 2014 indicate that rates have remained stable since 2002. In contrast, the new data suggest that rates have been declining significantly in New Zealand since 2008, at a rate of 1.3% per year (95% CI = 0.4–2.1). The previously unpublished data for Denmark show that the underlying trend in melanoma incidence between 1982 and 2010 was similar to the trends of neighboring Sweden and Norway. However, melanoma incidence in Denmark has plateaued since 2011, but not in Norway or Sweden. To explore these national trends further, we examined age-specific rates in the period of 2011–2014. We found that melanoma rates had stabilized in all age groups for New Zealand, for those younger than 60 years in Australia, and in those younger than 40 years in Denmark (see Supplementary Figure S1 online).Figure 2Age-standardized melanoma incidence (US 2000 population) from 1982 through 2015 and annual percentage change in four populations. (a) US whites. (b) Canada. (c) Australia. (d) New Zealand. The most recent data points (2012–2014/2015) are marked red. APC, annual percentage change; ASR, age standardized rate (US 2000).View Large Image Figure ViewerDownload Hi-res image Download (PPT) These data confirm that trends in melanoma incidence are continuing to diverge across populations. In North America and some countries in northern Europe, melanoma rates are rising with no signs of abating, although the rate of increase varies across countries. In contrast, in Australia, New Zealand, and Denmark, it appears that melanoma rates have plateaued and may even be declining. These latter three countries have arguably taken more steps toward implementing multicomponent, community-wide skin cancer prevention programs than any others (US Department of Health and Human Services, 2014US Department of Health and Human ServicesThe Surgeon General’s call to action to prevent skin cancer.https://www.surgeongeneral.gov/library/calls/prevent-skin-cancer/call-to-action-prevent-skin-cancer.pdfDate: 2014Google Scholar). Australia has a long history of coordinated and broad-reaching prevention campaigns, beginning in the early 1980s, whereas in the United States, United Kingdom, Norway, Sweden, and New Zealand, such programs were implemented at least a decade later. In Canada, there is no nationally coordinated approach to skin cancer prevention, and efforts at the provincial level have been limited in scope (Joshua, 2012Joshua A.M. Melanoma prevention: are we doing enough? A Canadian perspective.Curr Oncol. 2012; 19: e462-e467Crossref PubMed Scopus (12) Google Scholar). In Denmark, a 10-year national sun safety campaign began in 2007 (Koster et al., 2010Koster B. Thorgaard C. Philip A. Clemmensen I.H. Prevalence of sunburn and sun-related behaviour in the Danish population: a cross-sectional study.Scand J Public Health. 2010; 38: 548-552Crossref PubMed Scopus (47) Google Scholar). Population-based surveys conducted before and after initiation of the campaign have shown significant reductions in the proportion of Danes using sunbeds, specifically among the group who were traditionally high users, young people aged 15–25 years (Koster et al., 2009Koster B. Thorgaard C. Clemmensen I.H. Philip A. Sunbed use in the Danish population in 2007: a cross-sectional study.Prev Med. 2009; 48: 288-290Crossref PubMed Scopus (49) Google Scholar, Koster et al., 2018Koster B. Meyer M.K. Andersson T.M. Engholm G. Dalum P. Sunbed use 2007–2015 and skin cancer projections of campaign results 2007–2040 in the Danish population: repeated cross-sectional surveys.BMJ Open. 2018; 8: e022094Crossref PubMed Scopus (11) Google Scholar, Meyer et al., 2017Meyer M.K.H. Koster B. Juul L. Tolstrup J.S. Bendtsen P. Dalum P. et al.Sunbed use among 64,000 Danish students and the associations with demographic factors, health-related behaviours, and appearance-related factors.Prev Med. 2017; 100: 17-24Crossref PubMed Scopus (9) Google Scholar). The multicomponent, population-based campaigns implemented in Australia (Iannacone and Green, 2014Iannacone M.R. Green A.C. Towards skin cancer prevention and early detection: evolution of skin cancer awareness campaigns in Australia.Melanoma Manag. 2014; 1: 75-84Crossref PubMed Google Scholar) have resulted in positive changes in behavior related to sun exposure (Dobbinson et al., 2015Dobbinson S.J. Volkov A. Wakefield M.A. Continued impact of SunSmart advertising on youth and adults’ behaviors.Am J Prev Med. 2015; 49: 20-28Abstract Full Text Full Text PDF PubMed Scopus (25) Google Scholar, Volkov et al., 2013Volkov A. Dobbinson S. Wakefield M. Slevin T. Seven-year trends in sun protection and sunburn among Australian adolescents and adults.Aust N Z J Public Health. 2013; 37: 63-69Crossref PubMed Scopus (86) Google Scholar), and studies evaluating the campaigns in the United States and United Kingdom have shown more modest improvement in sun-protective behaviors (Boyle et al., 2010Boyle R. O’Hagan A.H. Donnelly D. Donnelly C. Gordon S. McElwee G. et al.Trends in reported sun bed use, sunburn, and sun care knowledge and attitudes in a U.K. region: results of a survey of the Northern Ireland population.Br J Dermatol. 2010; 163: 1269-1275Crossref PubMed Scopus (20) Google Scholar, Miles et al., 2005Miles A. Waller J. Hiom S. Swanston D. SunSmart? Skin cancer knowledge and preventive behaviour in a British population representative sample.Health Educ Res. 2005; 20: 579-585Crossref PubMed Scopus (58) Google Scholar). Sunbeds were banned in all Australian states by the end of 2015; however, before the ban, the prevalence of sunbed use was lower in Australia (11%) than in the United States (35%) and Europe (42%) (Wehner et al., 2014Wehner M.R. Chren M.M. Nameth D. Choudhry A. Gaskins M. Nead K.T. et al.International prevalence of indoor tanning: a systematic review and meta-analysis.JAMA Dermatol. 2014; 150: 390-400Crossref PubMed Scopus (211) Google Scholar), where legislation has restricted use by children/adolescents in some, but not all, jurisdictions (Le Clair and Cockburn, 2016Le Clair M.Z. Cockburn M.G. Tanning bed use and melanoma: establishing risk and improving prevention interventions.Prev Med Rep. 2016; 3: 139-144Crossref PubMed Scopus (32) Google Scholar, Pawlak et al., 2012Pawlak M.T. Bui M. Amir M. Burkhardt D.L. Chen A.K. Dellavalle R.P. Legislation restricting access to indoor tanning throughout the world.Arch Dermatol. 2012; 148: 1006-1012Crossref PubMed Scopus (61) Google Scholar). In interpreting the temporal trends in melanoma incidence, consideration should be given to the effects of migration patterns. An increase in the proportion of migrants who are constitutionally at lower risk of melanoma compared with the resident population would lead to artificially reduced observed incidence rates due to dilution of the at-risk population (Czarnecki, 2014Czarnecki D. The incidence of melanoma is increasing in the susceptible young Australian population.Acta Derm Venereol. 2014; 94: 539-541Crossref PubMed Scopus (20) Google Scholar). The proportion of migrants has increased for all countries examined over the period of 1990–2015, most markedly in Norway, New Zealand, and Sweden (see Supplementary Figure S2 online). The proportion of older (≥65 years) relative to younger (≤19 years) migrants is highest in Australia and New Zealand (see Supplementary Figure S3 online); incidence rates are continuing to rise in the older age group in both countries (see Supplementary Figure S1). Denmark, in comparison, has a higher proportion of young migrants; however, incidence is very low in the 0–19-year-old age group (see Supplementary Figure S1). In the most recent time period of 2010–2015, the proportion of migrants from Asia and Africa has increased in Sweden, Norway, Australia, and New Zealand, but not in Denmark. Thus, although population dilution may contribute to the observed stabilization of melanoma incidence rates in New Zealand and Australia, it is not yet having a detectable effect in Sweden or Norway and is unlikely to account for the recent declines observed in Denmark. The structure of all of these populations has also changed, with more older people and fewer younger people than the US 2000 standard population; this tends to enhance the impact of changes occurring in young age groups relative to changes in older age groups. It is too early to tell if the current trends in melanoma incidence in Australia, New Zealand, and Denmark will be sustained over time. Continued monitoring is needed to inform melanoma control efforts in these jurisdictions and in those where incidence rates continue to rise unabated. Catherine M. Olsen: http://orcid/org/0000-0003-4483-1888 Adele C. Green: http://orcid/org/0000-0002-2753-4841 Nirmala Pandeya: http://orcid/org/0000-0003-1462-4968 David C. Whiteman: http://orcid/org/0000-0003-2563-9559 The authors state no conflict of interest. The study was supported by a Program Grant (APP1073898) from the National Health and Medical Research Council of Australia (NHMRC). DCW is supported by a Research Fellowship from the NHMRC. Download .pdf (.41 MB) Help with pdf files Supplementary Data