Sunscreen But Not “Cancer-Screen”? A Review of Sunscreen as a Preventative Measure against Skin Cancer

“Photo-aging & UV-Protection” (n.d.). Creative Bioarray. Retrieved on February 8th, 2020. https://www.creative-bioarray.com/application/photo-aging-uv-protection.htm

Nearly 5 million Americans are treated for skin cancer annually (The surgeon general’s call to action to prevent skin cancer, 2014). In fact, the National Institute of Cancer recognized skin cancer as the most common form of the disease in the American population (Skin Cancer (Including Melanoma)-Patient Version, n.d.). Because  sunscreen can effectively reduce a specific spectrum of ultraviolet radiation (UVR) (Tanner, 2006), it has become a popular form of protection in American households. However, we should not rely on sunscreen as the ultimate shield from skin cancer.

Most prominent skin cancers are categorized into two types: non-melanoma and melanoma. The non-melanoma skin cancer (NMSC) is the most commonly diagnosed and less lethal skin cancer, and 95% of NMSC can be categorized as  basal or squamous cell carcinoma (Didona, Paolino, Bottoni, & Cantisani, 2018; Rowe et al, 2015; Sommers et al, 2017). Even though factors such as skin pigmentation and family history do contribute to the risk of skin cancer (The surgeon general’s call to action to prevent skin cancer, 2014), UVR exposure remains the most substantial risk factor for both non-melanoma and melanoma skin cancers. According to wavelength, UVR is divided into UVA (320–400nm) and UVB (290-320nm); exposure to the latter  can directly damage the structure of DNA, while UVA can indirectly increase the risk of skin cancer by damaging tertiary structures (Raffa, Pergolizzi, Taylor, & Kitzen, 2019).


“What Is Skin Cancer?” (2019).  Centers for Disease Control and Prevention, Centers for Disease Control and Prevention, retrieved on February 8th, 2020. www.cdc.gov/cancer/skin/basic_info/what-is-skin-cancer.htm.

Thus, the most effective way of reducing the risk of skin cancer is by minimizing UVR exposure. For average individuals, the largest source of UVR is exposure to sunlight. However, it is both unrealistic and unwise to thoroughly avoid sun exposure,especially given that it is essential for vitamin D production (Kelly, Friedberg, Calvi, Van Wijngaarden, & Fisher, 2010). Rather, a layer of sunscreen can reduce the amount of UVR absorbed by the skin, simultaneously acting as protection against skin cancer. 

However, researchers are still debating sunscreen’s effectiveness as a protectant for skin cancers. On one hand, current in-vivo evidence does support sunscreens’ effectiveness at limiting  skin cancer to some degree (Olsen, 2017). For instance, broad-spectrum sunscreen is considered to be capable of decreasing the rate of new precancerous lesions and reducing squamous cell carcinoma (Gallagher, 2005). Gordon and his colleagues also regard  sunscreen as a cost-efficient, widely accessible method of prevention for Caucasians in sub-tropical areas (2009). On the other side, some researchers have argued that the use of sunscreen as a sun protectant is limited. The Sun Protection Factor (SPF) scale, which is the current standard for categorizing sunscreen, only assesses a sunscreen’s capability of minimizing sunburn (Raffa, 2019). As sunburn is mainly associated with UVB, Raffa states that many sunscreens with high SPF lack protection against UVA radiation. Poon, Barnetson, and Halliday further argue that SPF fails to correlate with protection against both UVA and UVB radiation (2003). Whether the SPF scale can indicate skin cancer protection still remains controversial. Furthermore, fabric is considered the most important photoprotection against UVR (Aguilera, 2014) and a more effective alternative. And as artificial sunscreen correlates with the bleaching of corals (Raffa et al, 2019), people should reconsider if there are better alternatives than sunscreen.

When you are enjoying your holiday at a sunny beach, don’t assume that you are free from skin cancer because of your SPF 50 sunscreen. Even though sunscreen can protect you from UV radiation, it should not solely relied upon when it comes to avoiding skin cancer. You may not feel the burn, but it is likely that UVA is still damaging the DNA in your skin. In addition to  applying a thick layer of sunscreen, you should consider enjoying the same beautiful view under a nice, big umbrella.

Edited by: Lauren Flamenbaum

Placed by: Muskan Dubey

References

Aguilera, J., de Gálvez, M. V., Sánchez‐Roldán, C., & Herrera‐Ceballos, E. (2014). New advances in protection against solar ultraviolet radiation in textiles for summer clothing. Photochemistry and photobiology, 90(5), 1199-1206.

Didona, D., Paolino, G., Bottoni, U., & Cantisani, C. (2018). Non Melanoma Skin Cancer Pathogenesis Overview. Biomedicines, 6(1), 6. https://doi.org/10.3390/biomedicines6010006

Gallagher, R. P. (2005). Sunscreens in melanoma and skin cancer prevention. Cmaj, 173(3), 244-245.

Gordon, L. G., Scuffham, P. A., van der Pols, J. C., McBride, P., Williams, G. M., & Green, A. C. (2009). Regular Sunscreen Use Is a Cost-Effective Approach to Skin Cancer Prevention in Subtropical Settings. Journal of Investigative Dermatology, 129(12), 2766–2771. https://doi-org.proxy.library.emory.edu/10.1038/jid.2009.141

Kelly, J., Friedberg, J., Calvi, L., Van Wijngaarden, E., & Fisher, S. (2010). A case-control study of ultraviolet radiation exposure, vitamin D, and lymphoma risk in adults. Cancer Causes & Control,21(8), 1265-1275. Retrieved February 24, 2020, from www.jstor.org/stable/40792972

Olsen, C. M., Wilson, L. F., Green, A. C., Biswas, N., Loyalka, J., & Whiteman, D. C. (2017). Prevention of DNA damage in human skin by topical sunscreens. Photodermatology, photoimmunology & photomedicine, 33(3), 135-142.

Poon, T. S., Barnetson, R. S., & Halliday, G. M. (2003). Prevention of immunosuppression by sunscreens in humans is unrelated to protection from erythema and dependent on protection from ultraviolet A in the face of constant ultraviolet B protection. Journal of investigative dermatology, 121(1), 184-190.

Raffa, R. B., Pergolizzi, J. V., Taylor, R., & Kitzen, J. M. (2019). Sunscreen bans: Coral reefs and skin cancer. Journal of Clinical Pharmacy & Therapeutics, 44(1), 134–139. https://doi-org.proxy.library.emory.edu/10.1111/jcpt.12778

Rowe, C. J., Law, M. H., Palmer, J. M., MacGregor, S., Hayward, N. K., & Khosrotehrani, K. (2015). Survival outcomes in patients with multiple primary melanomas. Journal of the European Academy of Dermatology & Venereology, 29(11), 2120–2127. https://doi-org.proxy.library.emory.edu/10.1111/jdv.13144

Skin Cancer (Including Melanoma)-Patient Version. (n.d.). National Cancer Institute. Retrieved on February 23th, 2020, from https://www.cancer.gov/types/skin

Sommers, L. W., Steenbakkers, R. J. H. M., Bijl, H. P., Vemer-van den Hoek, J. G. M., Roodenburg, J. L. N., Oosting, S. F., Halmos, G. B., de Rooij, S. E., & Langendijk, J. A. (2017). Survival Patterns in Elderly Head and Neck Squamous Cell Carcinoma Patients Treated With Definitive Radiation Therapy. International Journal of Radiation Oncology, Biology, Physics, 98(4), 793–801. https://doi-org.proxy.library.emory.edu/10.1016/j.ijrobp.2017.02.214

Tanner, P. R. (2006). Sunscreen product formulation. Dermatologic clinics, 24(1), 53-62.The surgeon general’s call to action to prevent skin cancer. (2014). Reports of the Surgeon General. U.S. Dept of Health and Human Services.


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