Welcome back to the journal review. This is the July 2026 issue of JAMA Dermatology, and today we're focusing on a single piece — a research letter titled "Global Skin Cancer Burden From 1990 to 2023 and Projection to 2050." Let's get into it.

This is best described as a cross-sectional, registry-based epidemiologic study — essentially a global burden-of-disease analysis with a forecasting component tacked on. The group, based out of Shenzhen, pulled data from the Global Burden of Disease database, or GBD, for its 2023 release, and used it to characterize three malignancies together — melanoma, cutaneous squamous cell carcinoma, and basal cell carcinoma — across geography, sex, age, and something called the Sociodemographic Index, or SDI, which is a composite score running from zero to one that blends fertility rates in the under-25 population, educational attainment in adults, and lagged income per capita. Think of SDI as a proxy for a country's overall development and, by extension, its healthcare infrastructure and screening capacity.

Why this design? The authors don't spell out an extensive rationale beyond wanting a comprehensive epidemiologic snapshot, but the methodological logic here is fairly self-evident: you cannot get randomized trial data on population-level skin cancer incidence, so a burden-of-disease framework pooling multiple national and subnational data sources is really the only way to characterize global trends, especially in regions without robust cancer registries. The interesting analytic wrinkle is the forecasting piece — they used a Bayesian age-period-cohort model, or BAPC, which is a hierarchical Bayesian approach that separately models age effects, calendar-period effects, and birth-cohort effects, then projects them forward to 2050 with uncertainty intervals baked in. This is a fairly standard technique in GBD-adjacent forecasting papers, and it's a reasonable way to extrapolate epidemiologic trends without pretending you have certainty you don't have. One methodological detail worth flagging for anyone who works with GBD data: for basal cell carcinoma specifically, they excluded 2005 to 2009 from the model fitting because that window has a known surveillance artifact in the GBD data — essentially a documented reporting anomaly — so they fit projections only on 2010 to 2023 data. That's a sensible and transparent adjustment, though it does mean the basal cell carcinoma projections rest on a shorter observation window than the other two cancers.

Now to results, and the headline is geographic divergence. In 2023, disease burden — measured in disability-adjusted life-years, or DALYs, meaning years lost to premature death plus years lived with disability — was concentrated in high-SDI regions. Melanoma prevalence was highest in Oceania, exceeding 300 cases per 100,000. Squamous cell carcinoma peaked in high-income Western countries, particularly the US, at over 200 per 100,000. Basal cell carcinoma was highest across Oceania, North America, and Northern Europe. None of that will surprise anyone in this audience.

What's more clinically interesting is the trend data from 1990 to 2023, because the trajectory diverges sharply by development level. Low- and middle-SDI regions showed consistent incidence increases across all three cancers, with melanoma growth that's genuinely striking — roughly a two-and-a-half to three-fold increase in East Asia and in Andean Latin America. High-income Asia-Pacific followed a similar upward path. But high-income North America told a different story entirely: melanoma incidence actually declined by about one in ten, while squamous cell carcinoma more than doubled — up roughly 150 percent — and basal cell carcinoma rose about a third. So in the region most of us practice in, keratinocyte carcinoma is climbing while melanoma incidence is, at least by this metric, easing.

The DALY trends mirror this. Melanoma DALYs fell globally, and fell substantially in high-SDI settings — down about a third in both North America and Central Asia. Meanwhile squamous cell carcinoma DALYs rose sharply in low-SDI settings, up around 93 percent, essentially doubling. Basal cell carcinoma DALYs were globally stable but rose notably in East Asia and high-income Asia-Pacific, each up around 40 to 45 percent.

By sex, males had higher prevalence across all three cancers throughout the study period — nothing new there. For melanoma specifically, 2023 prevalence was about 28 per 100,000 in males versus 26 per 100,000 in females, and both sexes saw a decline from 2010 to 2023, a bit steeper in men. Age-stratified data showed melanoma prevalence rising most in patients 70 and older, while it actually declined in the 30-to-49 age bracket — a pattern that echoes what's been reported in younger cohorts in the US and Australia. A decomposition analysis — essentially partitioning how much of the case-count change is attributable to population growth versus true epidemiologic shift — found that population growth was the main driver behind rising squamous cell and basal cell carcinoma case numbers, whereas melanoma's rise, particularly in lower-SDI regions, was driven more by genuine epidemiologic change, not just more people existing.

And then the forward-looking piece. The Bayesian projections through 2050 show continued global burden growth across the board. Melanoma DALYs are projected to go from around 2 million in 2025 to more than 3.3 million by 2050. Squamous cell carcinoma DALYs are projected to more than triple, from about 1.2 million to 4 million. And basal cell carcinoma is projected to carry the single highest total DALY burden of the three, approaching 5 million by mid-century. Low- and middle-SDI regions are expected to see the steepest growth curves across all three cancers — which tracks with everything else in this paper.

On discussion and limitations — the authors frame this as confirming a familiar high-income-country narrative, melanoma burden stabilizing or declining while keratinocyte carcinoma keeps climbing, consistent with US Cancer Statistics data and Australian surveillance showing declining melanoma in patients under 40 alongside rising keratinocyte carcinoma. But the real contribution of this paper is capturing what registry-based studies from wealthy countries systematically miss: a rising burden in low- and middle-SDI populations who are underrepresented in the datasets we usually cite. The authors attribute the divergence partly to differential healthcare access and screening infrastructure — high-SDI regions have mature dermatologic surveillance systems that catch disease earlier, which paradoxically can inflate detected incidence even as mortality-weighted burden falls, whereas low-SDI settings likely have real underdiagnosis, meaning the numbers reported here may still be an underestimate of true burden. They're upfront about this: GBD estimates lean on modeling to fill gaps in incomplete reporting and weak health infrastructure in lower-resource settings, so take the absolute low-SDI figures as a floor, not a ceiling. They also caution, appropriately, that any BAPC projection out to 2050 assumes current policy and resource-allocation trajectories hold — a assumption that's inherently fragile over a 25-year horizon.

So what should you actually take from this. Nothing here is practice-changing in the sense of altering how you manage an individual patient tomorrow — this is a descriptive epidemiologic letter, not an intervention or outcomes study. But it's a useful macro-level orientation piece. The clearest actionable signal for those of us in high-income practice is confirmation of something you're probably already living: keratinocyte carcinoma volume, especially squamous cell carcinoma, is the growth curve to plan capacity around in North America, not melanoma, whose incidence is flattening or declining here even as it explodes elsewhere. If you have any connection to global health initiatives, training pipelines, or telederm outreach, the genuinely important finding is that melanoma incidence is rising two- to three-fold in East Asia and Andean Latin America, and that basal cell carcinoma is quietly becoming the single largest DALY contributor worldwide by 2050 — which argues for prioritizing keratinocyte carcinoma prevention and workforce training in the regions currently least equipped to absorb that burden. File this one under important context rather than something that changes your Monday clinic.

That's the full episode for this issue. Thanks for listening, and I'll see you in the next review.