No robust evidence supporting an association between tattoos and de-novo cutaneous melanoma

The recent Swedish study by Rietz Liljedahl et al. examining melanoma riskamong tattooed individuals has prompted critical discussion regarding a potential causal linkbetween tattoos and melanoma. While concerns persist that tattoo pigments deposited in thedermis may induce melanoma, several lines of evidence argue against this hypothesis, includingthe rarity of melanomas arising within tattoos, low incidence reported in nationwide studies, andthe absence of cases involving multiple melanomas within a single tattoo. Importantly, mostmelanomas in the Swedish study were not located at tattoo sites, and recent studies from theUnited States and France failed to demonstrate a positive association, with one reporting adecreased melanoma risk among individuals with multiple large tattoos. Experimental data evensuggest a possible protective effect of black ink on UV penetration. The study's interpretation isfurther limited by insufficient consideration of established melanoma risk factors, includingfamilial history, number of nevi, childhood sunburns, and sunbed use, the latter showing a highlysignificant association. Methodological issues also arise from the inclusion of dysplastic nevi withhigh-grade atypia as melanoma in situ, despite the lack of diagnostic consensus and poorinterobserver reliability. Moreover, comparisons between tattoo-related hydrocarbon exposureand occupational exposure in the petroleum industry are inappropriate due to substantialdifferences in magnitude, duration, and route of exposure. Overall, the study appears tooveremphasize hypothetical systemic effects of tattoo pigments while underestimating well-established behavioral and phenotypic risk factors. Current evidence does not support a directcausal link between tattoos and melanoma.