Skin Cancer and Photoprotection in People of Color

During the 2021 Skin of Color Update virtual conference, Dr. Maritza Perez opened her lecture by sharing her goal: to assess what is known about skin cancer and photoprotection in people of color. Dr. Perez is a member of the American Academy of Dermatology, who commissioned a workforce to look into this subject.

What is known about the epidemiology of keratinocyte carcinomas in people of color?

There is no tumor registry for keratinocyte carcinomas, so data stems from literature review. In a cohort retrospective study by Asgari et al. in Northern California of patients from 1998-2012, the total number of basal cell cancers diagnosed was 221,624 of which 348 (0.2%) of patients were Black, 1520 (1%) were Asian, and 4519 (3.1%) were Hispanic. Tripathi et al. evaluated the incidence of cutaneous SCC in the national inpatient service from 2009-2015. Out of 15,784 hospitalized patients with cutaneous SCC, 6.08% of patients were African American, 4.69% were Hispanic, 1.14% were Asian, and 0.13% were American Indian. Higgins et al performed a meta-analysis of incidence of keratinocyte tumors in people of color. After evaluating over 35 publications published between 1947-2017, the incidence of keratinocyte carcinomas was found to be 5% in Hispanic patients, 4% in Asian patients, and 2% in African American patients.

Dr. Perez’s take-away point: The incidence of keratinocyte carcinoma in people of color is 5% in Hispanic patients, 4% in Asian patients, and 2% in African American patients.  

Is there evidence in the literature of an association of sun exposure with keratinocyte carcinoma in people of color?

The main association of sun exposure with keratinocyte carcinoma is seen in Hispanic patients with basal cell carcinomas of the head and neck. A limited association is seen with sun exposure and squamous cell carcinoma in African Americans. In this population, squamous cell carcinoma is associated with chronic inflammation and scarring and with a 20-40% risk for metastasis, poor outcomes, and health disparities.

Dr. Perez’s take-away point: In Hispanic patients, keratinocyte carcinomas are sun related. In African American patients, keratinocyte carcinomas are associated with chronic scarring, a 20-40% risk for metastasis, poor outcomes, and health disparities.

What is known about the epidemiology of malignant melanoma in people of color?

Demographics vary based on geographical location.  Clairwood et al. published findings from a registry of patients in Connecticut from 1992-2007, which revealed that of 27,675 cases, 120 patients (1.6%) with malignant melanoma were Black, and 290 patients (2.3-4.3%) were Hispanic. Cockburn et. al reviewed cases of patients from the California Cancer Registry from 1988-2003 and identified an emergent epidemic of malignant melanoma amongst Hispanic patients at an increased rate of 1.8% per year yielding an incidence of 4.1 per 100,000. In a study published by Hu et al. of cancer data in Florida from 1990-2004, 3.6% of patients identified were Hispanic. For meta-analyses, Wu et al. evaluated 38 population-based cancer registries and identified 21.9 cases per 100,000 in white patients, 4.73 cases per 100,000 in Hispanic patients, 1.04 cases per 100,000 in African American patients, 4.52 cases per 100,000 in American Indian/Alaska Native patients, and 1.46 cases per 100,000 in Asian Pacific Islander patients. While the incidence of malignant melanoma is lower in people of color, there is a difference in outcome. Patients tend to be younger with more advanced disease and poorer prognosis

Dr. Perez’s take-away point: The incidence of malignant melanoma per 100,000 cases: 21.9 in White patients, 4.73 in Hispanic patients, 1.04 in African American patients, 4.52 in American Indian/Alaska Native patients, and 1.46 in Asian Pacific Islander patients.

What about the association of malignant melanoma with sun exposure in people of color?

Lopes at al. performed a systematic review of articles evaluating UV exposure and risk of malignant melanoma. Of the 13 articles that met criteria, only 2 had noted a weak association in Black and/or Hispanic males. In a multi-ethnic cohort study published by Park et al., invasive melanoma was associated with a sunburn susceptibility phenotype index including hair color, eye color, tanning ability, and reactivity of the skin to acute sunlight

Dr. Perez’s take-away point:  There is a limited association of melanoma with sun exposure in people of color.

What is known about the aging process in people of color?

In the multi-decade and ethnicity study, patients from multiple decades of life (20s-70s) and multiple ethnicities (Caucasian, and patients of African, Chinese, and Hispanic descent) were studied with regards to the appearance of their skin, skin structure and genomics at multiple body sites (face, arm, buttocks). Biopsies of exposed and non-exposed areas demonstrated elastosis in the dermis in Caucasian patients beginning at age 40, whereas in patients of Chinese and Hispanic descent it was not present until age 60, and in those of African descent there was no evidence of elastosis even up to age 60. Elastosis is the signature of the aging face, and cellular senescence is a key cause of aging. Removal of senescent cells has been shown to prevent or delay tissue dysfunction and age-related disorders. This can be measured through the levels of expression of the CDKN2A gene which encodes p16. In sun exposed sites there is an increased expression of CDKN2A which is seen across ethnicities. Autophagy, or cellular recycling, is another important principle of aging. In areas exposed to the sun on the face, genes involved in autophagy are lost. Sun exposure, lack of moisturizing, low aerobic exercise and smoking are also associated with loss of autophagy.

What is known about photodermatoses in people of color?

Lupus is more prevalent in African Americans compared to Hispanic and Asian patients. These patients demonstrate decreased minimal erythema dose to UVB. Sun protection can prevent the development of new lesions in 96% of patients. Dermatomyositis is 4 times more common in African Americans and these patients also demonstrate a reduced minimal erythema dose to UVB.  Sun avoidance, sun protective clothing, and high SPF are key recommendations for patients with lupus and dermatomyositis.

Polymorophous light eruption is more prevalent in African Americans and UVA is implicated more than UVB. Treatment recommendations are geared towards this and include sunscreens with avobenzone and oral polypodium leucotomas. Solar urticaria is seen more frequently in Caucasian patients and is associated with the action spectrum of visible light, thus tinted filters are recommended.

Chronic actinic dermatitis is more prevalent in African Americans and characterized by a reduced minimal erythema dose to both UVB, UVA and visible light. Recommendations include strict photoprotection, avoidance of allergens and systemic anti-inflammatories. Drug induced photodermatosis is seen more commonly in Caucasian patients, related to UVA and treated with broad spectrum sunscreens. Vitiligo is seen in all skin types, characterized by UV induced erythema and multiple methods of sun protection are recommended including SPF, sun protective clothing, and shade-seeking. Melasma is most prevalent in the southern United States and near the equator and is mediated by UVA and visible light. Tinted sunscreens with titanium dioxide and iron oxide are recommended.

What are different methods of sun protection that we can recommended to patients?

Hats with a larger diameter, thick material, and weaving can provide an SPF of 7 for the nose, 3 for the cheeks, 5 for the neck ,and 2 for the chin. Protective clothing that is tightly woven, thick, and dark can reduce total UV transmission. Sunglasses with tinted lenses, wrap around style and with side shields can be effective. Interestingly trees with dense foliage can provide an SPF coverage of 4-50. When discussing sunscreen, amounts are important. Dr. Perez recommends 1 teaspoon for head, face, and neck; 1 teaspoon for each upper extremity; 2 teaspoons for the trunk (front and back) and 2 teaspoons for each lower extremity. Lastly window glass in residential or commercial buildings block UVB only, and some automobile windows block UVA in addition to UVB.

Dr. Perez’s closed her talk by sharing final thoughts for recommending sun protection in persons of color. Sun protection can prevent sun burn, prevent the aging process, is associated with a potential but not proven prevention of keratinocyte carcinoma, a potential but not proven prevention of malignant melanoma, prevention of exacerbation from photodermatosis and prevention of development and progression of pigmentary disorders.

This information was presented by Dr. Maritza Perez at the 2021 Skin of Color Update virtual conference held on September 10-12-2021. The above highlights from her lecture were written and compiled by Dr. Blair Allais.

Did you enjoy this article? Find more on Skin of Color Dermatology here.