The sociological basis of the skin cancer epidemic.

Given the precipitous rise in its incidence in recent decades, skin cancer has been recognized as a growing epidemic. We explore the sociological underpinnings of this epidemic, including: (1) aging of the demographic; (2) human ecologic factors (residing in areas with high ambient ultraviolet levels and a depleted ozone layer); (3) large-scale European migration to more equatorial latitudes; (4) social structures that for centuries minimized miscegenation and maximized segregation; (5) gender-based differences in sunbathing, tanning, sunscreen use, and clothing choice; (6) occupational ultraviolet exposure; (7) the complex interplay of socioeconomic status, race, and urbanization on skin cancer incidence and mortality; (8) the effects of war on skin cancer incidence; (9) cultural shifts in clothing, travel, outdoor sports, recreation, and attitudes towards being tan; and (10) the indirect effects of religion. We show that without these sociological factors, the most common type of cancer would not be nearly as common.

Skin cancer: role of ultraviolet radiation in carcinogenesis.

UV radiation is a carcinogen known to play a role in the development of non-melanoma and melanoma skin cancers. Acute and chronic exposure to UV radiation causes clinical and biological effects that promote the unregulated proliferation of skin cells. In recent decades, changes in climate and increased air pollution have led to environmental changes that increase UV light transmission. In this chapter, we discuss sources of UV radiation that are relevant to human health, as well as the acute and chronic effects that result from UV radiation exposure.

Sunscreens: a review of health benefits, regulations, and controversies.

Ultraviolet radiation plays a major role in the development of nonmelanoma and melanoma skin cancers. Photoprotection by sunscreens has been shown to prevent the development of actinic keratosis, squamous cell carcinoma, melanoma, and photoaging. However, these benefits are only derived if the users apply sunscreen appropriately and practice other sun protection measures. This review discusses the health benefits provided by sunscreen use, updates the latest regulatory landscape on sunscreen, and addresses the controversies and limitations associated with sunscreen use.

Photoprotection: part I. Photoprotection by naturally occurring, physical, and systemic agents.

The acute and chronic consequences of ultraviolet radiation on human skin are reviewed. An awareness of variations in naturally occurring photoprotective agents and the use of glass, sunglasses, and fabric can lead to effective protection from the deleterious effects of ultraviolet radiation. New systemic agents, including Polypodium leucotomos, afamelanotide, and antioxidants have potential as photoprotective agents.

Current status of photoprotection by window glass, automobile glass, window films, and sunglasses.

Ultraviolet radiation (UVR) has known adverse effects on the skin and eyes. Practitioners are becoming more aware of the importance of outdoor photoprotection. However, little attention is directed to the exposure of the skin and eyes to UVR through the window glass or sunglasses. The amount of ultraviolet transmission through glass depends mainly on the type of the glass. All types of commercial and automobile glass block the majority of ultraviolet-B; however, the degree of ultraviolet-A transmission depends on the type of glass. Laminated glass offers better UVA protection than tempered glass; new safety regulations for automobiles may result in increased use of laminated glass for side windows. Window films can be applied to glass to increase UVR protection. Sunglasses need to be compliant with one of the national standards; a wraparound style or side shields offer the best protection. Increased understanding by practitioners on the transmission of UVR through glass, window films, and sunglasses would allow them to better educate the public and to better manage photosensitive patients.

The evolution of sunscreen products in the United States--a 12-year cross sectional study.

Excessive exposure from ultraviolet (UV) radiation contributes to the development of skin cancers and photoaging. Topical sunscreen products remain one of the most widely used forms of protection for the majority of the public. The objective of this analysis was to examine photoprotection trends (e.g., SPF value) and the degree of UVA I protection from 1997 to 2009 in the United States. Sunscreen products purchased and evaluated in 1997 (N = 59), 2003 (N = 188) and again in 2009 (N = 330), totaling 577, were included in this analysis. Information regarding (1) the SPF value, (2) name and concentration of the active ingredients, (3) type of products (i.e., daily vs. recreational/beach), and (4) claims of UVA protection was recorded and analyzed. In addition, the critical wavelength (CW) of 330 products from 2009 was determined. The results showed an increase in the SPF values of products from 1997 to 2009. The percentage of low SPF products (SPF 4-14) decreased from 27% in 1997 to 6% in 2009. The number of products containing a known UVA-I filter (i.e., avobenzone or zinc oxide) increased from 5% in 1997 to 70% in 2009. Lastly, approximately, 225 (68%) of the products tested in 2009 attained CW > 370 nm. In the past decade, sunscreen products have undergone fundamental improvements, the most significant of which is the breadth of protection against UVA I.

From the bottle to the skin: challenges in evaluating antioxidants.

Endogenous production and ultraviolet-generated free radicals in the skin can lead to photoaging and even skin cancer. Topical antioxidants have been found to provide benefits against ultraviolet damage and these ingredients have been incorporated into various cosmetic products and claimed to have substantial effects. Currently, there is a lack in a standardized rating system to measure the concentration and activity levels of antioxidants in these products. As a result, it is difficult for consumers and clinicians to evaluate and select commercial products based on readily accessible evidence. In this review, we will describe four assays which have been used to measure antioxidants in various products, and the strengths and weaknesses of each test will be detailed. We will highlight key considerations for clinicians when interpreting the results of antioxidant tests when evaluating commercial products containing antioxidants.

Sunscreens: obtaining adequate photoprotection.

Adequate photoprotection plays a paramount role in reducing the burden of both photoaging and photocarcinogenesis. The scope of photoprotective strategies employed by the public, from most to least effective, includes: sun avoidance, seeking shade, the use of protective clothing, and the application of sunscreen. Among these options, sunscreen use remains the strategy most frequently employed by the public--a reversal of the preferred order of photoprotection. Given this trend, it is clear why sunscreens invariably take center stage in any discussion regarding obtaining adequate photoprotection.

The role of antioxidants in photoprotection: a critical review.

Free radicals have long been studied as a contributor to aging and disease processes. Endogenous production of radicals from cellular metabolism and exogenous sources from ultraviolet radiation and pollution can damage the skin on the cellular and tissue levels. Although the body possesses an elegant defense system to prevent radical damage, this innate system can be overwhelmed and lead to a state of oxidative stress or immunosuppression, and can even trigger carcinogenesis. Topical supplementation of antioxidants can provide additional protection to neutralize reactive oxygen species from both endogenous and exogenous sources. This review will discuss our current understanding of the mechanisms of free radical damage and evaluate the potential benefit of topical antioxidants in sunscreens and skin care products.

Dermoscopic features of basal cell carcinomas: differences in appearance under non-polarized and polarized light.

BACKGROUND: Basal cell carcinomas (BCCs) can be diagnosed using different dermoscopic modalities. OBJECTIVE: To evaluate dermoscopic features of BCCs using nonpolarized and polarized dermoscopy to highlight similarities and differences between dermoscopic modalities. MATERIALS AND METHODS: Retrospective study of 149 BCCs under nonpolarized dermoscopy (NPD), polarized contact dermoscopy (PCD), and polarized noncontact dermoscopy (PNCD). Images were evaluated for a range of dermoscopic colors, structures, and vessels. Features were compared according to histopathologic subtype. RESULTS: The most common dermoscopic structures in BCCs across all modalities included globules (50.3-51.0%), dots (49.7-50.3%), white structureless areas (63.1-74.5%), structureless gray-brown areas (24.2-24.8%), and ulcerations (28.2%). The most frequently observed vasculature included arborizing vessels (18.8-38.3%), short fine telangiectasias (SFTs) (73.8-82.6%), and vascular blush (41.6-83.2%). Structures with higher levels of agreement across modalities included pigmented structures and ulcerations. Lower levels of agreement existed between contact and noncontact modalities for certain vascular features. White shiny structures, which include shiny white lines (chrysalis and crystalline structures) (0-69.1%), shiny white areas (0-25.5%), and rosettes (0-11.4%), exhibited no agreement between NPD and polarized modalities. CONCLUSIONS: This study highlights differences in dermoscopic features of BCCs under three dermoscopic modalities. Shiny white lines (chrysalis and crystalline structures) and shiny white areas may be used as additional criteria to diagnose BCCs.

Photoprotection in the era of nanotechnology.

Commercial sunscreen based on nano-sized titanium dioxide (TiO(2)) and zinc oxide (ZnO) delivers superior UV protection and reduces whitening on skin compared to the older generations of inorganic sunscreens. This review discusses the historical use of nano-sized TiO(2) and ZnO in sunscreen and the relationship between UV attenuation and the primary particles, aggregates and agglomerates that make up these inorganic oxides. In addition we reviewed the recent safety concerns surrounding these materials, specifically, percutaneous penetration of TiO(2) and ZnO nanoparticles through human skin and their potential to cause phototoxicity.

Detection of early basal cell carcinoma with dermoscopy in a patient with psoriasis.

A 49-year-old man with a history of basal cell carcinoma and psoriasis presented for routine skin exam and psoriasis management. He had multiple erythematous, scaly patches and plaques, originally diagnosed as psoriasis. Noticeably, one erythematous patch had a focal erosion. Dermoscopy revealed arborizing vessels, an erosion, pink structureless areas, and short, fine telangiectasias (SFTs), suggestive of superficial basal cell carcinoma (sBCC). Dermoscopy of all other lesions was consistent with psoriasis, exhibiting dotted vessels on a faint erythematous background. In conclusion, sBCCs may be overlooked in patients with multiple psoriatic plaques. In this case, the lesions were all initially presumed to be psoriasis. After detecting an erosion, the clinician was prompted to inspect further with dermoscopy and biopsy. Suspicion of sBCC was confirmed after visualization of dermoscopic structures consistent with sBCC. We highlight this case to encourage the use of dermoscopy in these patients for prompt diagnosis of BCCs.

Current sunscreen controversies: a critical review.

BACKGROUND/PURPOSE: Sunscreens are believed to be a valuable tool in providing photoprotection against the detrimental effects of UV radiation, a known carcinogen. However, a number of controversies have developed regarding their safety and efficacy. This review summarizes the relevant studies surrounding these controversies. METHODS: Evidence of the prevention of skin cancer, an oft-cited reason for sunscreen use, was examined as it pertains to squamous cell carcinoma, basal cell carcinoma and melanoma. We also reviewed studies examining the effects of sunscreen on the synthesis of vitamin D, an essential nutrient whose role in health and disease continues to grow. Lastly, we analyzed studies surrounding the safety and toxicity of oxybenzone, retinyl palmitate and nanoparticles of zinc oxide (ZnO) and titanium dioxide (TiO2 ). RESULTS: The overwhelming majority of available data is drawn from studies conducted using antiquated sunscreen formulations. Nonetheless, our research revealed that topical use of sunscreen protects against squamous cell carcinoma, does not cause vitamin D deficiency/insufficiency in practice and has not been demonstrated to adversely affect the health of humans. CONCLUSION: Given the established benefits of UV protection, the use of sunscreens remains an important part of an overall photoprotective strategy. Future sunscreens with improved formulation should ideally offer superior protection. With increased usage of sunscreen by the public, continuous and vigilant monitoring of the overall safety of future products is also needed.

Noninvasive imaging technologies in the diagnosis of melanoma.

The incidence of melanoma has increased during the last few years. Melanoma care and survival can be improved by early diagnosis, which can be facilitated by the use of noninvasive imaging modalities. Here we review 5 modalities available in clinical practice. Total body photography is used to follow patients at high risk for melanoma by detecting new lesions or subtle changes in existing lesions. Dermoscopy is an effective noninvasive technique for the early recognition of melanoma by allowing clinicians to visualize subsurface structures. Computer-assisted diagnostic devices are fully automated analysis systems with the capacity to classify lesions as benign or malignant with limited involvement from clinicians. Confocal scanning laser microscopy is an in vivo and noninvasive technology that examines the skin at a resolution comparable to that of histology. High-resolution ultrasound is an adjunct diagnostic aid mainly for the early detection of lymph node metastasis. Applications and limitations of each technology are discussed.