USA: Study on UV Exposure and Keratinocyte Carcinoma in Skin of Color

A recent study in JAMA Dermatology has found that in people with skin of color, the association between UV exposure and keratinocyte carcinoma (KC) may be dependent on the type of UV exposure. This includes a positive association with UV exposure via the sun but no association with phototherapy.

Exposure to ultraviolet radiation (UV) is an important modifiable risk factor for KC in fair-skinned non-Hispanic White populations; however, there is less certain evidence for this relationship in those with darker skin. To fill this knowledge gap, Elysha Kolitz, The University of Texas Southwestern Medical Center, Dallas, and colleagues aimed to assess and synthesize the published data concerning the association between UV exposure and the risk of KC in people with skin of color.

For this purpose, the researchers searched the online database from database origin through January 2022. It included studies with UV exposure as a risk factor for KC in individuals with skin of color, defined as any race other than non-Hispanic White, Fitzpatrick skin types IV to VI, or tanning ability of rarely or never burns. Measures of exposure included the UV index, irradiance, latitude, history of phototherapy, history of sunburn, or occupational exposure. Evidence quality was assessed using the Oxford Centre for Evidence-Based Medicine guidelines.

The meta-analysis included 12 articles, with clinical data spanning the years 1990 to 2019. More than 32,970 KCs in individuals with skin of color were included.

Key Findings of the Study

• Eight studies found no association between UV exposure and KC, while 4 studies showed a positive association.
• Study types included 1 ecological study, 9 cohort studies, and 2 case-control studies.
• The quality of the studies was rated from moderate to low (2b to 4).

"Our results showed that there is moderate to low quality evidence assessing the association of UV exposure with KC," wrote the authors. "The studies that found no association were among patients receiving phototherapy. Small positive associations were found in primarily East Asian individuals among studies assessing nonphototherapy-related UV exposure." No studies were performed in the US, no studies among Black individuals, and only 1 study among a Hispanic population.

"Further research is required to better assess whether these associations exist across populations of patients with darker skin types," they concluded.

Reference

Kolitz E, Lopes FCPS, Arffa M, Pineider J, Bogucka R, Adamson AS. UV Exposure and the Risk of Keratinocyte Carcinoma in Skin of Color: A Systematic Review. JAMA Dermatol. Published online March 23, 2022. doi:10.1001/jamadermatol.2022.0263

Keywords

JAMA, UV exposure, keratinocyte carcinoma, ultraviolet rays, skin of color, darker skin, skin color, skin cancer, phototherapy, Elysha Kolitz, fair skin