Revisiting the evidence: UV exposure, melanoma and the need for smarter public health strategies

The association between melanoma and exposure to ultraviolet radiation (UV) has been thoroughly investigated throughout the years. Notably, the three-part meta-analysis by Gandini et al., which dedicated its second part specifically to UV radiation, has shaped the way that we evaluate risk factors for melanoma.¹ Despite the multifaceted pathogenesis of melanoma, several global campaigns promoting sun protection have been implemented in response to these findings. The SunSmart campaign in Australia, for example, recently published a cost-effectiveness and return-on-investment analysis, reporting an impressive return of $8.70 for every $1 spent.² This benefit is reflected in the prevention of melanoma, melanoma-related deaths and gains in quality-adjusted life years. However, despite the apparent simplicity of the solution, there remains a critical need for ongoing epidemiological research. This is essential to capture shifts in trends and behaviours over time and necessitates the continuous collection of accurate and robust data.

The paper by Kwa et al.³ effectively synthesizes data from studies published over the past two decades on sun exposure and melanoma. Findings highlight that both a history of sunburn and cumulative sun exposure are significant contributors to melanoma development. However, this paper also aggregates data across Fitzpatrick skin phototypes I–IV, which is noteworthy given that most research and public health messaging tend to focus predominantly on phototypes I and II. This narrow emphasis may influence patient perceptions and behaviours, potentially leading individuals with darker skin phototypes to underestimate their risk. A recent survey paper reported that although up to 90% of patients were aware that sun exposure could be harmful, over 83% (including patients with dark phototypes) had experienced at least one sunburn in their lifetime.⁴ In addition, 13% and 26% (phototypes I and VI, respectively) did not use any form of photoprotection.⁴

Another interesting observation from the paper by Kwa et al.³ is the significant disparity in epidemiologic data collection across different contexts and regions. These disparities encompass a wide range of issues, from patient recall bias to inconsistencies in the definition of terms such as ‘sunburn’. While attempts have been made in the past to standardize melanoma-related data collection—such as through the development of the Melanostrum questionnaire⁵—data heterogeneity continues to pose a challenge. This variation can dilute the strength of epidemiologic findings and lead to conflicting reports and inconclusive findings. For instance, in this meta-analysis,³ some of the included studies reported no association between the use of UV tanning beds and melanoma, while others did find a significant link. Furthermore, the paper reported a range of 1.23–8.48 positive odds ratios for >1 sunburn and positive associations for UV index and outdoor leisure activity, among others (quality of evidence 3B).

The value of revisiting epidemiological data and conducting meta-analyses lies in offering a more critical perspective on existing knowledge and how it can be effectively applied. It allows for the identification of knowledge gaps that warrant focused research, shaping better-targeted public health messaging—especially to reach populations at risk—and improving our own practices, in both data collection practices and clinical care strategies.

ES: nothing to declare. CG has received research support by BMS, Delcath, Novartis, Pierre-Fabre, Regeneron and Sanofi. He is a member of the advisory board of Beiersdorf, BioNTech, BMS, Delcath, Immunocore, MSD, Novartis, Pierre-Fabre, Regeneron, Sanofi, SUN Pharma and SkylineDX. He has received honoraria by Bioderma, BMS, Delcath, Immatics, Immunocore, MSD, Novartis, Onkowissen, Pierre-Fabre, Regeneron, Sanofi, SUN Pharma, SkylineDX and Sysmex. CG is a board member of the DeCOG (ADO), unpaid; a board member of the European Association of Dermato-Oncology (EADO), unpaid; a scientific board member of the Melanoma World Society (MWS), unpaid; he is a board member of the Hiege Stiftung—Die Deutsche Hautkrebsstiftung, unpaid. CG is a board member of the Roggenbuck Stiftung, unpaid. CG is scientific of Melanoma Info Deutschland (MID), unpaid. He is co-Founder of Dermagnostix and Dermagnostix R&D.