UV Exposure and Melanoma Risk in Patients With Skin of Color

Although ultraviolet (UV) radiation exposure is a well-established risk factor for melanoma in fair-skinned individuals, in whom 90% of melanomas affect sun-exposed surfaces, there is uncertainty regarding this association for people of color.¹ Research findings have demonstrated that individuals belonging to racial minority groups often present with melanomas in sun-protected areas.² Acral lentiginous melanoma, the most commonly diagnosed subtype in Black and Asian patients, is associated with worse survival rates compared with superficial spreading melanoma, the type most frequently diagnosed in non-Hispanic White patients.³

Other results have shown higher cancer-specific mortality rates for nodular melanoma and lentigo melanoma among Black patients compared with White patients, as well as deeper tumors and higher rates of ulceration and lymph node positivity in Black vs White patients with several different types of melanoma.⁴ In a 2017 study, Black patients presented with deeper tumors for superficial spreading (1.26mm vs 0.83 mm), nodular (3.50mm vs 2.93 mm), and lentigo maligna (1.07mm vs 0.63 mm) melanoma (P  < .001), and tumor ulceration was more often present among Black vs White patients (36.2% vs 26.3%, P  <.05) with acral lentiginous melanoma.⁴ In patients with nodular melanoma, lymph node positivity was observed in 21.8% of Black patients compared with 17.8% of White patients (P  = .01).

Overall, people of color are generally diagnosed with melanoma at more advanced stages and have lower 5-year survival rates and worse outcomes compared with White patients, underscoring the pressing need to clarify risk factors and effective interventions for these populations.⁵ In a review published in December in JAMA Dermatology,  Lopes, et al examined the link between UV exposure and the risk for cutaneous melanoma in people of color; people of color was defined as individuals of any race or ethnicity other than non-Hispanic White, those with Fitzpatrick skin types IV through VI, and those with a tanning ability of rarely or never burns.⁶

Of the 548 studies assessed, the 13 studies that met inclusion criteria (7 ecological studies, 5 cohort studies, and 1 case-control study) were of moderate to low quality and comprised more than 7,700 melanomas. No association was observed between UV exposure and melanoma in 11 studies, and the other 2 studies found small but significant associations in Black and Hispanic men.

These results suggest that “UV exposure may not be an important risk factor for melanoma development in people with skin of color,” and “…recommendations promoting UV protection for melanoma prevention in skin of color are not supported by most current studies,” the study authors concluded. However, they note the need for additional research to clarify these points.⁶

To further discuss these findings and related clinical implications, we interviewed Raja Sivamani, MD, MS, AP, integrative dermatologist and associate professor of clinical dermatology at the University of California, Davis, in Sacramento, and lead editor of wellness platform Jivome and integrative educational website LearnSkin.com.

What are your thoughts about the results of the recent review by Lopes, et al?

This study sheds light on the need for more complex conversation on how we approach skin of color. First, the study raises awareness that individuals with darker skin may have a different risk profile in regards to UV exposure and melanoma. However, we have to be careful in that many of the studies included in this systematic review did not actually measure pigmentation level and only referred to ethnicity or focused on Fitzpatrick skin types, which can be crude and have wide variation in the type 3 to 4 region.

Therefore, we do not know if there was a higher risk in those with less skin pigmentation since they may have been grouped in the overall analysis. This is the problem with studies that try to group everyone into one big group. Secondly, sun exposure can still have detrimental effects such as melasma and uneven skin pigmentation in those with darker skin, so we still need to emphasize high-quality sun protection habits among those with skin of color. 

What are the implications of these findings for clinicians? In particular, how should POC be advised about UV protection for melanoma prevention?

While this study is interesting, the findings will not change my practical approach to how I counsel my patients with skin of color. People with darker skin still need to protect from sun exposure because they are still at risk for sun damage and sun-related changes like melasma. So, my approach isn’t to just focus on melanoma but to focus on their skin more globally and emphasize the need to use tinted zinc oxide-based sunscreens with iron oxides, along with the other important aspects of sun protection such avoidance of intense sunlight, sun-protective clothing, and the use of sun-protective foods and oral supplements. 

What should be the focus of additional research regarding this topic?

One of the major limitations in the current research into those with skin of color is that we are still relying on ethnicity or Fitzpatrick skin types, and both are likely too crude when trying to differentiate those with Fitzpatrick types of 3 to 5. A better approach would be to use more objective techniques that directly measure the pigmentation level, and future studies should assess skin cancer risk against an objective pigmentation measure. 

References

1. Dermatology education – melanoma. Skin of Color Society. Melanoma | Skin Cancer in Skin of Color | Melanoma in blacks (skinofcolorsociety.org) Accessed on January 3, 2021.

2. Kundu RV, Patterson S. Dermatologic conditions in skin of color: part I. Special considerations for common skin disorders. Am Fam Physician. 2013;87(12):850-856. PMID:23939567

3. Culp MB, Lunsford NB. Melanoma among non-Hispanic Black Americans. Prev Chronic Dis. 2019;16:E79. doi:10.5888/pcd16.180640

4. Mahendraraj K, Sidhu K, Lau CS, McRoy GJ, Chamberlain RS, Smith FO. Malignant melanoma in African-Americans: a population-based clinical outcomes study involving 1106 African-American patients from the Surveillance, Epidemiology, and End Result (SEER) database (1988-2011). Medicine (Baltimore). 2017;96(15):e6258. doi:10.1097/MD.0000000000006258

5. Ferguson NN. Challenges and controversy in determining UV exposure as a risk factor for cutaneous melanoma in skin of color. JAMA Dermatol. Published online December 16, 2020. doi:10.1001/jamadermatol.2020.4615

6. Lopes FCPS, Sleiman MG, Sebastian K, Bogucka R, Jacobs EA, Adamson AS. UV exposure and the risk of cutaneous melanoma in skin of color: a systematic review. Published online December 16, 2020. JAMA Dermatol. doi:10.1001/jamadermatol.2020.4616