SUNSCREEN, SKIN CANER

UV Radiation & Skin Cancer

Ultra violet (UV) radiation is a form of electromagnetic radiation that naturally is emitted from the sun. There are three different types of UV radiation: UVA, UVB, and UVC. UVA rays have the least energy but can cause skin cells to age and can cause indirect damage to cells’ DNA. UVA is linked to long-term skin damage like wrinkles. UVB rays have more energy than UVA rays and can directly damage cells’ DNA. These rays are the main cause of sunburn and cause the most skin cancers. UVC rays have the highest energy of the three but they do not pose a risk to humans due to the fact that they react with ozone in the atmosphere before they are able to reach the ground. Sunlight is the main way that humans are exposed to UV radiation although there are some manmade mechanisms such as tanning beds and welding torches. UVA and UVB rays are not equally emitted by the sun. about 95% of the UV rays are UVB while 5% are UVA. The strength of the rays reaching humans varies according to several different factors. UV rays are strongest midday (10am-4pm) as well as during the spring and summer seasons. Exposure to UV radiation decreases as your location gets farther from the equator. UV radiation exposure may also be increased in areas with water, sand, snow, or pavement due to the rays’ ability to bounce off these surfaces (American Cancer Society).

There are three main types of skin cancer that can be caused by UV radiation: basal cell carcinoma, squamous cell carcinoma, and melanoma. These three types vary in their origin, severity, and treatment. Basal cell carcinoma (BCC) is the most common type of skin cancer. It originates in the basal cells of the skin and looks like a flesh-colored round growth, pearl-like bump, or a pinkish patch of skin. This type is common on the head, neck, and arms. Squamous cell carcinoma (SCC) is the second most common type of skin cancer and looks like a red firm bump scaly patch, or a sore than heals and then reopens. This type tends to form on skin that gets the most sun exposure like the rim of the ear, face, neck, arms, chest, and back. Melanoma is the most serious type of skin cancer with the highest tendency to spread to other tissues. It can develop within a mole already present on the skin or appear as a dark spot. Each of these types of skin cancer occur at a higher rate in people with lighter complexions (American Academy of Dermatology).

Treatment of basal cell carcinoma involves standard surgical excision as first-line treatment. Curettage and electrodesiccation is an alternative first-line option in which the affected skin is scraped off. Similar to BCC, SCC also involves standard surgical excision as a first-line treatment option. Mohs surgery which is a specialized tissue-sparing procedure is also an option for SCC. Melanoma is usually treated by removing the affected cells by wide excision. Wide excision of melanoma is generally performed down to the muscle fascia unlike the excision used for BCC or SCC. Depending on whether or not the melanoma has spread, treatment may include more invasive therapy (Gershenwald). While the surgical removal of skin cancer is a viable treatment option, it is still best to prevent skin cancer from occurring in the first place by staying out of the sun at an early age or wearing protective clothing when being in the sun is unavoidable.

Resources:

Gershenwald J, Keung E. Surgical management of primary cutaneous melanoma. UpToDate. https://www.uptodate.com/contents/surgical-management-of-primary-cutaneous-melanoma-or-melanoma-at-other-unusual-sites?search=treatment+of+melanoma&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2#H1701593750. Accessed March 15, 2022.

Skin cancer: Types and treatment. American Academy of Dermatology. https://www.aad.org/public/diseases/skin-cancer/types. Accessed March 15, 2022.

Ultraviolet (UV) radiation. American Cancer Society. https://www.cancer.org/cancer/cancer-causes/radiation-exposure/uv-radiation.html#:~:text=UV%20rays%2C%20either%20from%20the,actinic%20keratosis%2C%20and%20solar%20elastosis. Published July 10, 2019. Accessed March 15, 2022.

Sunscreen and Skin Cancer

The sun is the skin’s worst enemy. Sun exposure can lead to sunburns which increases the risk of skin cancer. Skin cancer starts when abnormal cells in the epidermis are growing out of control. The main types of skin cancer are basal cell carcinoma, squamous cell carcinoma and melanoma. Basal cell carcinoma is the most common form of skin cancer, and is caused by a combination of intermittent, intense exposure and cumulative, long-term exposure to UV radiation from the sun. It usually develops on skin areas typically exposed to the sun such as the face, ears, neck, scalp, shoulders and back. Squamous cell carcinoma is the second most common form of skin cancer, and is caused by cumulative, long-term exposure to UV radiation from the sun and tanning beds. It usually develops on sun-exposed areas. Melanoma is the most dangerous form of skin cancer, and it is estimated that there will be 197,700 new cases in the U.S. in 2022. It is caused by intense, intermittent sun exposure and tanning beds. It can be found anywhere on the body, even in areas that are not typically exposed to the sun.

The use of sunscreen can reduce the danger posed by UV radiation. UV radiation is part of the natural energy produced by the sun, and there are two types of UV light that contribute to the risk of skin cancer. UVA accounts for 95% of UV radiation that reaches the Earth’s surface with fairly constant intensity over the day. It penetrates the ozone, clouds, and window glass. It also penetrates the human skin more deeply and is associated with skin aging. UVB, on the other hand, accounts for 5% of the UV radiation that reaches the Earth’s surface with varied intensity that peaks around midday. It is partially absorbed by the ozone and clouds and does not penetrate window glass. It is not absorbed as deeply into the skin and is associated with skin burning. UVA is connected to the “broad-spectrum protection” and UVB is connected to the Sun Protection Factor (SPF) on sunscreen product labels. SPF indicates how long the sun’s radiation would take to redden your skin with sunscreen compared to without sunscreen.

There are two types of sunscreen: physical (mineral) and chemical. Physical sunscreen has ingredients like titanium dioxide and zinc oxide, and they block and scatter UV rays before it penetrates the skin. Chemical sunscreen has ingredients like oxybenzone, avobenzone, octocrylene and ecamsule, and they absorb UV rays before it damages the skin. Physical sunscreens may cause less skin irritation than chemical sunscreens, but both are tested as safe and effective.

Everyone over the age of 6 months should be using sunscreen daily that is broad spectrum with an SPF 15 or higher. It is found that using SPF 15 sunscreen daily can reduce the risk of developing squamous cell carcinoma by about 40 percent. SPF 15 is ideal for daily use, but SPF 30 or higher is necessary for extended outdoor activities. No matter the SPF, sunscreen should be applied 30 minutes before going outside and reapplied every two hours and immediately after swimming or sweating. It is necessary to apply sunscreen daily, even when it is cloudy because up to 80 percent of UV radiation reaches the earth. Sunscreen application should not be limited only to the face, but also to the entire body.

Sunscreen alone isn’t enough, going under the shade and wearing sun-safe clothing, a wide-brimmed hat and UV blocking sunglasses are also important.

References:

1. Green AC, Williams GM. Point: sunscreen use is a safe and effective approach to skin cancer prevention. Cancer Epidemiol Biomarkers Prev. 2007;16(10):1921-1922. doi:10.1158/1055-9965.EPI-07-0477

2. Sander M, Sander M, Burbidge T, Beecker J. The efficacy and safety of sunscreen use for the prevention of skin cancer. CMAJ. 2020;192(50):E1802-E1808. doi:10.1503/cmaj.201085

3. “Skin Cancer Information.” The Skin Cancer Foundation, 20 Jan. 2022, https://www.skincancer.org/skin-cancer-information/.

4. “Sunscreen.” The Skin Cancer Foundation, 28 Jan. 2022, https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/.

5. “UV Radiation.” The Skin Cancer Foundation, 28 Jan. 2022, https://www.skincancer.org/risk-factors/uv-radiation/.

Melanoma

Melanoma is the most serious form of skin cancer due to its ability to quickly spread to other organs if not detected at an early stage. This type of skin cancer isn’t discussed as much as carcinomas because it isn’t as common. Melanomas make up less than five percent of all skin cancers.

Melanoma occurs when there is DNA damage due to ultraviolet radiation that triggers mutation sin melanocytes. Melanocytes are skin cells that produce melanin when the skin is exposed to IV radiation. Treatment for melanoma varies throughout the different stages. In the early stages, it can be treated with surgery where the melanoma is removed. Towards the later stages, an attempt to remove the melanoma can be made along with targeted drug therapy and use of immunotherapy. The immunotherapy drugs are called checkpoint inhibitors such as pembrolizumab and nivolumab. These drugs are generally the first drugs used because they have the capability to shrink tumors in certain patients for long periods of time.

Ipilimumab is another checkpoint inhibitor that is usually not a drug used as first line treatment. It sometimes be used in combination with pembrolizumab or nivolumab. Due to the risk of serious side effects, this combination should be carefully considered.

The New England Journal of Medicine has an article based on a study comparing the efficacy of ipilimumab and nivolumab combination compared to the drugs being used alone in melanoma. In this study, the primary endpoints were progression-free survival and overall survival between the groups. There were three study groups comprised of 945 patients with previously untreated advanced melanoma were randomized 1:1:1 to receive nivolumab plus ipilimumab, nivolumab plus placebo, and ipilimumab plus placebo. All the patients in this study had unresectable or metastatic histologically confirmed stage III or stage IV melanoma. The efficacy endpoints were based on the intention-to-treat population. At 60 months, they followed up to assess overall survival, progression-free survival, and the objective response rate at the 95% CI were performed. They found that overall survival was longer in the two nivolumab containing groups compared to the ipilimumab group. The overall survival at 5 years was 52% in the combination group, 44% in the nivolumab group, and 26% in the ipilimumab group. The median progression-free survival was 11.5 months in the combination group, 6.9 months in the nivolumab group, and 2.9 months in the ipilimumab group. In terms of safety, the combination group had the highest adverse event occurrence at 59%. 23% of the patients in the nivolumab group reported side effects. 28% of patients in the ipilimumab group reported side effects. Based on the results of this study, it was found that patients taking both ipilimumab and nivolumab had sustained long-term overall survival at 5 years as compared to patients taking only ipilimumab and only nivolumab. This study probably helped progress the guidelines in using these immunotherapy drugs in the treatment of melanoma. Now, it is possible to see ipilimumab and nivolumab be used in the same treatment regimen for melanoma. The study also confirmed the worse safety profile in the combination group compared to using the drugs individually, which should be carefully taken into consideration when treating melanoma.

References:

1. Larkin J, Chiarion-Sileni V, Gonzalez R, Grob JJ, Rutkowski P, Lao CD, Cowey CL, Schadendorf D, Wagstaff J, Dummer R, Ferrucci PF, Smylie M, Hogg D, Hill A, Márquez-Rodas I, Haanen J, Guidoboni M, Maio M, Schöffski P, Carlino MS, Lebbé C, McArthur G, Ascierto PA, Daniels GA, Long GV, Bastholt L, Rizzo JI, Balogh A, Moshyk A, Hodi FS, Wolchok JD. Five-Year Survival with Combined Nivolumab and Ipilimumab in Advanced Melanoma. N Engl J Med. 2019 Oct 17;381(16):1535-1546. doi: 10.1056/NEJMoa1910836. Epub 2019 Sep 28. PMID: 31562797.

2. “Treatment of Melanoma by Stage.” American Cancer Society, https://www.cancer.org/cancer/melanoma-skin-cancer/treating/by-stage.html.

Cemiplimab & CSCC

Cutaneous squamous-cell carcinoma (CSCC) continues to be the second most prominent skin cancer in the world, second only to basal-cell carcinoma. Many skin cancers can go undetected for years, allowing it to spread without notice and become more deadly than if caught early. The cancer becomes metastatic, spreading to different parts of the body and may no longer be susceptible to surgery or chemotherapy. Immunotherapy is an area of cancer treatment that has been more frequently used in patients in whom surgery or radiation therapy are no longer options. In many treatment regimens, we can see immunotherapy as first-line, adjunct to other therapies, or used alone when there are not many options left. An important aspect of immunotherapy is ensuring that the drug of choice will influence the tumor. Tumors become highly mutated as they grow in the body, and skin tumors even more so because of the exposure to chronic ultraviolet light. These highly mutated tumors will likely show a positive response to immunotherapy that have a checkpoint inhibition.

Cemiplimab is a monoclonal antibody that is targeted against immuno-checkpoint programmed cell death-1 (PD-1) receptors that are expressed on tumors. Its ligand, PD-L1, is expressed on antigen presenting cells, mesenchymal stem calls, mast cells, and other cells of the host immune system. PD-L1 is also expressed on tumor cells. Tumor cells that have a higher expression of PD-L1 suppress signaling pathways that are involved in T-cell activation, which allows the tumor to evade death by the host immune system. Immunotherapies that target this PD-1/PD-L1 pathway have been shown to have better therapeutic effects on tumors that express this immune checkpoint.

Before the approval of cemiplimab, there were no systemic therapies available to treat advanced cutaneous squamous cell carcinoma. Approval of cemiplimab was based on two clinical trials that assessed a durable objective response rate from a multi-center, dose-finding trial, on patients with different types of advanced tumors. Patients were enrolled in the trial regardless of prior treatment, but only if surgery or radiation were no longer recommended. The objective response rate (ORR) evaluated using the Response Evaluation Criteria in Solid Tumors (RECIST) criteria and an additional assessment using digital photography for patients with locally advanced tumors were used. Results of the studies show that among 108 patients with advanced disease (75 with metastatic disease and 33 with locally advanced) disease, the ORR was 47% (95% CI: 38, 57) with 4% complete and 44% partial response rates. For the 75 patients with metastatic disease, the ORR was 47% (95% CI: 35, 59) and 49% (95% CI: 31, 67) for the 33 with locally advanced disease.

Like most immunotherapy, the safety data includes serious immune mediated adverse reactions including pneumonitis, hepatitis, colitis, diabetes mellitus, and nephritis. Among patients with advanced cutaneous squamous cell carcinoma, cemiplimab produced a positive response in about half of the patients with a similar safety profile to other immunotherapy the work with the PD-1/PD-L1 pathway. Since its initial approval in 2018, the indications for cemiplimab have been expanded to include basal cell carcinoma and non-small cell lung cancer.

References:

1. Ahmed SR, Petersen E, Patel R, Migden MR. Cemiplimab-rwlc as first and only treatment for advanced cutaneous squamous cell carcinoma. Expert Rev Clin Pharmacol. 2019;12(10):947-951. doi:10.1080/17512433.2019.1665026

2. Zheng Y, Fang YC, Li J. PD-L1 expression levels on tumor cells affect their immunosuppressive activity. Oncol Lett. 2019;18(5):5399-5407. doi:10.3892/ol.2019.10903

3. Center for Drug Evaluation and Research. Cemiplimab-RWLC for cutaneous squamous cell carcinoma. U.S. Food and Drug Administration. https://www.fda.gov/drugs/drug-approvals-and-databases/fda-approves-cemiplimab-rwlc-metastatic-or-locally-advanced-cutaneous-squamous-cell-carcinoma. Accessed January 19, 2022.

Sunscreen

Written by: Hillary Pham and Jae Chang

Sunscreen has always been a recommended product to be used on individuals on a daily basis. Even when individuals do not plan to be outside, it is still recommended to wear sunscreen indoors. This is because UV rays can still emit indoors too, like at any openings such as a window. Health care providers over the years have promoted the use of sunscreen as it can cause serious health damages and conditions. Although sunlight is very vital for any individuals, it is also as important to wear sunscreen as well. Since, it is possible for any kind of sun rays to cause serious skin damages, such as skin cancer, due to the ultraviolet radiation of the sun.

UV rays can cause damaging effects on DNA. The association between UV rays and DNA is that UV rays can cause changes in the skin which causes actinic keratoses, a precursor of non-melanoma skin cancer (NMSC) and squamous cell carcinoma (SCC). It is said that NMSC is the most common type of malignancy in the United States. UV rays are categorized by either UVA and UVB, and while both types of UV rays are of concern, more attention is placed on UVA. NMSC and SCC are generally attributed to UVA radiation because UVA penetrates through the skin deeper than UVB. However, other factors including amount of sun exposure during childhood, genetic predisposition, pigmentation, and aging contribute to the risk for developing skin cancer.

To briefly explain the mechanism of UV rays that cause damage, UVA radiation exposure causes the formation of reactive oxygen species. The reactive oxygen species then damages DNA by breaking the tertiary structure of DNA. UVB is absorbed by DNA to cause similar structural damage. Furthermore, mutations in p53 tumor suppressor gene which is involved with DNA repair and apoptosis in cells with sustained DNA damage caused by UV ray exposure is associated with DNA damaging and skin malignancy development.

There are many sunscreens on the market. So, how do individuals know which to choose from? Sunscreen efficacy is based on a factor called the sun protection factor, or as most people know, SPF. For a long time, researchers and scientists have known that sunscreen is effective and beneficial to use. However, there is still an ongoing debate on what the precise SPF value is the absolute best to use. Nevertheless, the recommended range for SPF value is anywhere from 15 to 30, that studies have shown.

Studies have found that SPF only refers to the ability to protect the skin against sunburn and is unrelated to reducing the risk for skin cancer. Sunburn is caused by the skin’s exposure to sunlight, in particular, UVB. Therefore, the SPF portion of sunscreen is only meant for skin protection against sunburn and not the risk of developing skin cancer from UVA and UVB. Furthermore, SPF does not include protection against UVA. A study conducted by Poon and colleagues has demonstrated that immune protection factor or IPF was a better predictor of protection against UVA than SPF. Nevertheless, general studies all agree that broad spectrum sunscreens can decrease the rate of new precancerous lesions, which leads to less actinic keratoses and therefore fewer SCC. Unfortunately, there is little evidence of sunscreens protecting against basal cell skin cancers and melanomas.

In regard to application of the products, some scientists have argued that the sunscreen should be reapplied every 2 to 3 hours after the initial application. However, studies done by Diffey, et. al shows that “typically reapplication of sunscreen at 20 minutes results in 60% to 85% of the UV exposure if sunscreen were reapplied at 2 hours.” So, in conclusion, Diffey states that sunscreen should be first applied 15 to 30 minutes before going outside in any areas of the body that may be exposed to the sunlight. Then, to repeat the application again, after 15 to 30 minutes. And of course, after that any reapplication should be considered depending on what the individual may be doing or how long the individual is outside in the sun for.

Overall, there is still ongoing talk and research about the best SPF reapplication time period is between numerous researchers. Nevertheless, if there is one thing that all researchers, scientists, and providers can all agree on, it is that every individual should wear sunscreen every single day, no matter what their day may look like.

References:

Diffey, B. L. (2001). When should sunscreen be reapplied?. Journal of the American Academy of Dermatology, 45(6), 882-885.

Gasparro, F. P., Mitchnick, M., & Nash, J. F. (1998). A review of sunscreen safety and efficacy. Photochemistry and photobiology, 68(3), 243-256.

Raffa RB, Pergolizzi JV Jr, Taylor R Jr, Kitzen JM; NEMA Research Group. Sunscreen bans: Coral reefs and skin cancer. J Clin Pharm Ther. 2019 Feb;44(1):134-139. doi: 10.1111/jcpt.12778. Epub 2018 Nov 28. PMID: 30484882.

Natalie Eshaghian & Donna Salib

Sunscreens and Skin Cancer

Our skin is the largest organ of our bodies, however, it is also one of the most sensitive as well. Our skin is directly affected by the environment unlike the other organs in our body.1 Skin cancer is one of the most prominent cancers in the United States. There are different types of skin cancers ranging from non-melanoma skin cancers to melanoma which is the most severe form. Skin cancer is on the rise, where approximately 5 million people a year are diagnosed with skin cancer, so it is important to protect ourselves from the disease.2 There are multiple different risk factors for skin cancer, but the most predominant would be UV radiation. Although our bodies need natural UV radiation as a source of vitamins, excessive exposure is seen to deteriorate our skin and make it more susceptible to cancer.

There are two different UV radiations that are seen to be associated with skin cancer, UVA and UVB. UVA is seen to cause skin aging due to its long wavelength, and is seen in the use of tanning beds, whereas UVB causes skin burning because of its shorter wavelength. UVA is more harmful than UVB due to its longer wavelength and reaches deeper into the skin layers.3 Although UV radiation is one of the main causes of skin cancer, it is also one of the most important modifiable risk factors, meaning that it is a risk that can be easily prevented if changed.4 In the epidermis, there are cells called melanocytes and they release a dark pigment, known as melanin, when the skin cells are damaged by UV. Melanin is able to absorb UV light, acting as a UV shield, but melanin isn't able to completely prevent skin damage from UVB. Essentially, the melanin can begin to absorb the UV light and cause damaging effects to the skin.5 Many people with darker skin tones believe that they are void of developing skin cancers, however, it is still very possible to develop skin cancer in both light and dark skin tones due to excessive UV exposure.

There are 3 major types of skin cancer: basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), which are both classified as non-melanoma skin cancer, and melanoma.6 Basal cell carcinoma usually develops in areas of the body that was exposed to the sun, such as the face, however, the cancer cells grow slowly making it unlikely to become life-threatening. Squamous cell carcinoma also usually occurs in sun-exposed areas of the body, such as the face and hands, however, this type is more likely to spread. Melanomas are the most aggressive type of skin cancer and can develop anywhere on the body. Melanomas can develop in existing benign moles that become cancerous and can be cured if detected and treated early. If left untreated, melanomas can eventually lead to death. Studies have shown a significant decrease in incidences of squamous cell carcinomas and a reduced risk in invasive melanomas in people who use sunscreen daily.7

It is important to protect our skin from the excessive harmful effects of UV radiation. Some ways to protect oneself is using sunscreen with a sun protective factor (SPF) of 15 or higher. It is important to learn how to read sunscreen labels to know which is properly protecting your skin and which is not. Sunscreens are categorized as physical and chemical blockers.8 Sunscreen can either absorb or reflect UV photons before they reach our skin. Sunscreens that are considered physical blockers are those that act as a shield and deflect UV rays away from the skin. It usually contains two active mineral ingredients: zinc oxide and titanium oxide, which are the only two ingredients that have been labeled safe by the FDA. Recently, certain sunscreen brands and products were recalled because they contain a harmful chemical known as benzene, which is found to be carcinogenic. According to Johnson & Johnson, benzenes are found in many of our daily exposures, but it is a potential cancer causing substance, also known as a human carcinogen, depending on the level and extent of exposure.9 The very product we use to protect our skin from the harmful UV rays to prevent skin cancers is seen to be the source of causing cancers. It is important to distinguish the proper sunscreens to use with the correct ingredients to protect you from all types of harm.

Physical sunscreens that protect against both UVB and UVA are also labeled broad-spectrum. Chemical sunscreens absorb the UV rays and convert them into heat which is then released. Chemical sunscreens are not as long lasting as physical sunscreens, therefore it has to be frequently applied throughout the day and takes longer to work ranging from 30 minutes to 50 minutes compared to physical sunscreens which come into action instantly. According to the American Academy of Dermatology, it is recommended to choose a sunscreen that protects against both UVA and UVB with an SPF of either 30 or 50 depending on the weather.10 The sun protective factor (SPF) is determined by calculating the number of seconds it takes for the skin to be exposed. For example, if it normally takes about 10 minutes in the sun for a person’s skin to get burned without sunscreen, then theoretically if they were to use SPF 30, the sunscreen should last them 50 times as long, about 500 minutes. Nevertheless, the sunscreen should still be applied frequently about every 2 hours. In addition to sunscreens, a person can use protective clothing, such as long sleeves and pants, hats, etc. to shield themselves from the UV light, as well as simply staying out of the sun, especially when the sun’s rays are strongest between 10 a.m. and 4 p.m.2 Although people love to tan and stay in the sun during the sunny summer days, they could use these methods to help protect themselves and lower their risk of developing skin cancer. Sunscreen does not stop a person from getting that glowing tan, but will protect them from absorbing the harmful UV rays.

Cancer doesn’t discriminate, so it is important to note that all types of people can develop skin cancer due to excessive sun exposure, and we all need to protect ourselves from it. Furthermore, our body is delicate and it is important to protect ourselves from different forms of harm, such as chemicals as well as environmental conditions. As pharmacists, we need to educate the public on proper sun exposure and how to protect ourselves. Certain things like sunscreens are important to note and help a consumer read a label to ensure they are receiving the correct protection, as well as free of any other harmful chemicals, such as benzene. The sun may be our friend, but it can always turn on us. Skin-aging and non-melanoma skin cancers are largely preventable and it is our priority to help the world as a whole to educate on sun safety and protection.

References:

1 Rittié L, Fisher GJ. Natural and sun-induced aging of human skin. Cold Spring Harb Perspect Med. 2015;5(1):a015370. Published 2015 Jan 5. doi:10.1101/cshperspect.a015370

https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC4292080/

2 Watson M, Holman DM, Maguire-Eisen M. Ultraviolet Radiation Exposure and Its Impact on Skin Cancer Risk. Semin Oncol Nurs. 2016;32(3):241-254. doi:10.1016/j.soncn.2016.05.005

https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC5036351/

3 UV Radiation. The Skin Cancer Foundation. (2021, May 27). https://www.skincancer.org/risk-factors/uv-radiation/

4 D'Orazio J, Jarrett S, Amaro-Ortiz A, Scott T. UV radiation and the skin. Int J Mol Sci. 2013;14(6):12222-12248. Published 2013 Jun 7. doi:10.3390/ijms140612222 https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC3709783/

5Brenner M, Hearing VJ. The protective role of melanin against UV damage in human skin. Photochem Photobiol. 2008;84(3):539-549. doi:10.1111/j.1751-1097.2007.00226.x

6Nakayama K. Growth and progression of melanoma and non-melanoma skin cancers regulated by ubiquitination. Pigment Cell Melanoma Res. 2010;23(3):338-351. doi:10.1111/j.1755-148X.2010.00692.x

7 Sander M, Sander M, Burbidge T, Beecker J. The efficacy and safety of sunscreen use for the prevention of skin cancer. CMAJ. 2020;192(50):E1802-E1808. doi:10.1503/cmaj.201085

https://www-ncbi-nlm-nih-gov.jerome.stjohns.edu/pmc/articles/PMC7759112/

8 Latha MS, Martis J, Shobha V, et al. Sunscreening agents: a review. J Clin Aesthet Dermatol. 2013;6(1):16-26.

9 Johnson & Johnson. Content Lab U.S. 14th July,2021. Available at: https://www.jnj.com/johnson-johnson-consumer-inc-issues-voluntary-recall-of-specific-neutrogena-and-aveeno-aerosol-sunscreen-products-due-to-the-presence-of-benzene.

10 How to select a sunscreen. American Academy of Dermatology. Date Accessed: 23 July,2021 http://www.aad.org/public/spot-skin-cancer/learn-about-skin-cancer/prevent/how-to-select-a-sunscreen.

Sunscreen! Sunscreen! Sunscreen! Have you ever watched a dermatologist go through their skin care routine and not mention sunscreen? No? Me neither! One product that dermatologists unanimously agree on its importance is… you have guessed it! Sunscreen! Sunscreen provides many benefits for the skin starting with decreasing your risk of developing skin cancer. It also has anti-aging benefits as well as aiding in an even skin tone. Sunscreen helps against the damage that the sun can cause onto the skin. Skin cancer is when the outermost layer of the skin, the epidermis, is damaged due to DNA mutation. This leads to an abnormal cell growth in the epidermis. There are four different types of skin cancer that can occur; they are basal cell carcinoma (BCC), squamous cell carcinoma (SCC), melanoma, and Merkle cell carcinoma. Skin cancer mainly occurs from the harmful ultraviolet (UV) rays of the sun as well as the UV used in tanning beds.

The truth is, the word cancer on its own sounds very scary. It has a very negative connotation to it since most times people hear the words cancer then it is assumed to be associated with bad news. When it comes to skin cancer, if it is caught early then there is a great chance of eliminating the cancer before it spreads. Here is what you need to know about the different kinds of skin cancer. BCC is the most common type of skin cancer that occurs in the epidermis. It often develops in areas exposed to the sun such as the face, neck, shoulders, and back. If BCC is caught and treated early, it can be only cause destruction locally but rarely do these cancers spread to other parts of the body and become fatal. The second most common type of skin cancer is SCC. Just like BCC, SCC also occurs in the epidermis and often develops in areas that are exposed to the sun often such as face, neck, and hands and the skin is shown to have signs of sun damage such as wrinkles and age spots. If SCC is not detected and treated early then it can at times grow rapidly and spread which can be fatal. Melanoma is another type of skin cancer that develops from skin cells that produce melanin. Melanin is what gives us our skin color.

Melanoma often appears as a mole and it can be anywhere in the body not necessarily due to exposure to the sun. It can be also caused by tanning beds. It is one of the more rare and dangerous types of skin cancer but it is also curable if it is caught and treated early. Lastly, Merkel cell carcinoma (MCC) is the rarest type of skin cancer and it is very aggressive. It can appear as a painless tumor on an area of the body that is exposed to the sun but there is a high chance of it recurring and spreading throughout the body. Just like other types of cancer, early detection and treatment in crucial especially with MCC.

After learning about the different kinds of skin cancer, it is important to not only apply sunscreen but to understand how to apply it as well as the type of sunscreen that needs to be applied. Sunscreen comes with different protection factors. You may have heard and seen products that have SPF 15, SPF 30, SPF 50, etc. on it but what is the difference between each? Is there really a difference? SPF 15 helps protect against 93% of the UV rays of the sun and SPF 30 helps protect against 97% while SPF 50 protects against 98% of the sun rays. Any SPF that is higher than SPF 50 can protect more against the UV rays but it is an insignificant increase. It is recommended to use SPF 30 or more especially when spending a day outdoors.

Everyone should wear sunscreen daily and should apply it 30 minutes before going outdoors. Reapplication every 2 hours is crucial. There are different types of sunscreens that are present such as physical and chemical sunscreens. Physical sunscreens include ingredients such as zinc oxide and titanium dioxide and may cause less skin irritation than chemical sunscreens but nonetheless both types are safe to be used to protect against UV rays. Sunscreen is a great way to protect yourself against harmful UV rays but it is not completely effective on its own. Wearing long-sleeves, tight clothes, wide-brimmed hat and sunglasses as well as staying in the shade are additional ways that you can protect yourself against harmful UV rays. Stay safe!

Center, John Stoddard Cancer. “8 Reasons to Wear Sunscreen This Summer.” 8 Reasons to Wear Sunscreen | John Stoddard Cancer Center, 27 May 2020, www.unitypoint.org/desmoines/article.aspx?id=e0a22a4f-77c7-4a9a-b779-ed3c37956982.

“Skin Cancer Information.” The Skin Cancer Foundation, 1 June 2021, www.skincancer.org/skin-cancer-information/.

“Sunscreen.” The Skin Cancer Foundation, 28 May 2021, www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/.

Sunscreen will protect the skin against UVA/UVB rays produced by the sun, UV radiation is carcinogenic meaning it is a cause of skin cancer as well as premature skin aging, sunburns and cataracts. Ultraviolet A (UVA) has a longer wavelength and is able to enter the skin barrier leading to premature skin aging. Ultraviolet B (UVB) has a shorter wavelength and will damage the surface of the skin barrier leading to sunburns. Prolonged, unprotected sun exposure to UVB rays will lead to skin cancer more commonly squamous cell carcinoma (SCC), malignant melanoma and basal cell carcinoma (BCC).

Malignant melanoma is the deadliest form of skin cancer, where epidermal melanocytes are affected. Most melanomas are linked to pre-existing moles that a person may have and if it is caught in its early stages it can be surgically removed. BCC and SCC are non-melanomatous skin cancers that affect the epidermal keratinocytes, BCC and SCC are less deadly since they remain localized in the primary affected area. Treatment includes microsurgery, cryosurgery, resection and MOHS.

UV rays will generate reactive oxidative species (ROS) such as hydroxyl radical, superoxide anion, and hydrogen peroxide producing DNA mutations. ROS will cause free radical injury to nucleotide bases which will lead to mutagenesis, for example oxidative change may mutate a G/C pair to A/T pair. Mutations resulting from oxidative mutagenesis are found in tumors isolated from the skin leading to production of carcinogens. UV radiation directly affects nucleotide base pairing in DNA, pyrimidine bases are most susceptible to DNA mutation due to their UV absorption. UV radiation will lead to photo lesions that block DNA replication, impairs transcription and cause abnormal base pairings. UV induced DNA mutations are a major cause of melanomas and other skin cancers, due to the direct mutagenic role of UV radiation.

Sunscreens are vital to sun damage and skin cancer prevention. The two main categories of sunscreens are physical and chemical sunscreens, and come in a variety of forms including sunscreen sticks, oils, creams, liquids, sprays, and gels. Physical sunscreens are also known as mineral sunscreens and contain minerals for example zinc oxide or titanium dioxide. Physical sunscreens will reflect and scatter UVA/UVB rays before the rays entering the skin. Physical sunscreens are generally non-skin irritating and not known to cause many allergic reactions.

Chemical sunscreens contain UVA-absorbing ingredients such as avobenzone/benzophenone as well as UVB-absorbing ingredients. Sunscreens containing para-aminobenzoic acid (PABA) and benzophenone will cause skin reactions such as skin rashes, burning, blisters, redness and itchiness. However many chemical sunscreens have advantages in broader-spectrum coverage against solar radiation, meaning they’ll provide coverage against both UVA and UVB rays.

SPF found in sunscreens stands for sun protection factor, according to the FDA it is a measurement of how much UV radiation is needed to cause sunburns when using sunscreen. The higher the SPF content the longer the sun protection lasts, however the Skin Cancer Foundation recommends using a water-resistant broad spectrum sunscreen with minimum SPF of 30 when outdoors but if one is mostly indoors then SPF of 15 is fine. SPF is often included in other skincare and makeup products, for example some moisturizers, foundations, face powders, even lip balms will contain SPF.

Everyone requires sunscreen year round throughout all four seasons, and it is recommended to apply sunscreen thirty minutes prior to going outside with a re-application every two hours. Also sunscreen application should not only be limited to the face, the body should get a coverage of sunscreen as well. There are a range of sunscreens specifically formulated for the face or body available over the counter. For the ultimate skin protection, one must implement additional skin protection measures. Limit sun exposure as much as possible and avoid tanning beds because they also emit UV radiation also linked to skin cancer.

1. D'Orazio J, Jarrett S, Amaro-Ortiz A, Scott T. UV radiation and the skin. Int J Mol Sci. 2013;14(6):12222-12248. Published 2013 Jun 7.

2. Latha MS, Martis J, Shobha V, et al. Sunscreening agents: a review. J Clin Aesthet Dermatol. 2013;6(1):16-26.

3. Skin Cancer Foundation. All About Sunscreen. Updated 2021 January. Accessed 2021 May 24. https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/

4. Skin Cancer Foundation. Ask the Expert: Does a High SPF Protect my Skin better? Published 2020 June 9. Accessed 2021 May 24. https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/

5. Sunscreen: The Burning Facts. Environmental Protection Agency. Published 2006 September. Accessed 2021 May 24. Pages 1-6.

6. Food and Drug Administration. Sun Protection Factor (SPF). Updated 2017 July 14. Accessed 2021 May 24. https://www.fda.gov/about-fda/center-drug-evaluation-and-research-cder/sun-protection-factor-spf

Bottom line - everyone should use a broad-spectrum sunscreen with an SPF of 15 or more. (specifically SPF 15 for daily use versus SPF 30+ for extended outdoor activities like a beach trip or hiking trip). Sunscreen includes active ingredients that help prevent the sun’s UV radiation from reaching your skin. There are two broad categories that we can distinguish sunscreen into: physical and chemical sunscreens. Physical sunscreen ingredients block and scatter the rays before the penetrate your skin. Examples of these would be minerals like titanium dioxide and zinc oxide. Chemical sunscreen ingredients absorb the UV rays before they can damage your skin. Examples of these would be avobenzone and octisalate. It is important to note that the sunscreens that are labeled as organic or natural are essentially the same as others that are not. As noted by source 3, it is simply terms used as a marketing strategy. All active ingredients in sunscreens are chemically derived.

People often believe that the higher the SPF, the better the sunscreen. However, this is not true. SPF stands for Sun Protection Factor. This number tells us how long the sun’s UVB rays would take to redden your skin if you were to apply the sunscreen exactly as directed, compared to the amount of time without the sunscreen. Therefore, using an SPF 30 sunscreen would take you 30 times longer to burn than if you did not use the sunscreen.

Source 2 summarizes that sunscreens should not be the first or sole agent used for skin cancer prevention, but should be used in conjunction with clothing to prevent overexposure. There are indications that childhood sun exposure may be particularly important in the generation of basal cell carcinoma and melanoma later in life.

1. Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis, https://pubmed.ncbi.nlm.nih.gov/29620003/

2. Sunscreens in melanoma and skin cancer prevention, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180647/

https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/

Bottom line - everyone should use a broad-spectrum sunscreen with an SPF of 15 or more. (specifically SPF 15 for daily use versus SPF 30+ for extended outdoor activities like a beach trip or hiking trip). Sunscreen includes active ingredients that help prevent the sun’s UV radiation from reaching your skin. There are two broad categories that we can distinguish sunscreen into: physical and chemical sunscreens. Physical sunscreen ingredients block and scatter the rays before the penetrate your skin. Examples of these would be minerals like titanium dioxide and zinc oxide. Chemical sunscreen ingredients absorb the UV rays before they can damage your skin. Examples of these would be avobenzone and octisalate. It is important to note that the sunscreens that are labeled as organic or natural are essentially the same as others that are not. As noted by source 3, it is simply terms used as a marketing strategy. All active ingredients in sunscreens are chemically derived.

People often believe that the higher the SPF, the better the sunscreen. However, this is not true. SPF stands for Sun Protection Factor. This number tells us how long the sun’s UVB rays would take to redden your skin if you were to apply the sunscreen exactly as directed, compared to the amount of time without the sunscreen. Therefore, using an SPF 30 sunscreen would take you 30 times longer to burn than if you did not use the sunscreen.

Source 2 summarizes that sunscreens should not be the first or sole agent used for skin cancer prevention, but should be used in conjunction with clothing to prevent overexposure. There are indications that childhood sun exposure may be particularly important in the generation of basal cell carcinoma and melanoma later in life.

1. Use of sunscreen and risk of melanoma and non-melanoma skin cancer: a systematic review and meta-analysis, https://pubmed.ncbi.nlm.nih.gov/29620003/

2. Sunscreens in melanoma and skin cancer prevention, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1180647/

https://www.skincancer.org/skin-cancer-prevention/sun-protection/sunscreen/

Sun exposure is the most important environmental risk factor for skin cancer that can be limited by consistent sunscreen use and avoiding the sun. There is not a single dermatologist or doctor who would recommend against using sunscreen for all their patients, unless there is an absolute contraindication, such as allergies to multiple types of sunscreen filters or infants under six months of age. In addition to skin cancer, high cumulative solar UV exposure can cause photoaging and premature aging of the skin. Sun-induced photoaging is distinct from the natural aging process of the skin because sun-induced photoaging appears as dry, leathery skin with irregular hyperpigmentation, coarse wrinkling, and loss of skin elasticity. On the other hand, the skin naturally aged by time appears as smooth skin with fine wrinkling and thinning due to the loss of adipose tissue. Dermal elastosis, the accumulation of degraded elastotic material in the dermis, is typically used as a distinguishing feature of photoaged skin. The three major types of skin cancer include basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma. These are most common in the white Caucasian populations throughout the world who typically spend a lot of time outdoors doing activities like sunbathing on the beach. Clinical research and studies have shown support for the use of sunscreen as a safe and effective way to prevent sun cancer and photoaging. However, sunscreen is meant to be used as an adjunct to clothing and other methods of sun avoidance to protect from solar UV radiation. Sunscreen should be applied every day, regardless of weather, and even if someone plans to stay indoors all day. Generally, it is recommended to use a sunscreen with at least SPF 30 and reapply every two hours during the daytime to all areas on the body exposed to the sun. SPF (sun protection factor) refers to the ability of the sunscreen to protect against sunburn by looking at the ratio of how much solar energy (UVB radiation) is required to produce a sunburn on the skin with sunscreen to that without sunscreen. The larger the SPF value, the greater the sunburn protection, but the incremental benefit after SPF 30 decreases as the SPF increases. SPF is not related to protection against UVA radiation, which is more dangerous since it is able to penetrate deeper into the skin and cause biochemical changes that lead to skin cancer. Broad-spectrum UV filters are better because they absorb both UVA and UVB radiation, providing optimal protection against skin cancer.

Works Cited:

1. Iannacone MR, Hughes MC, Green AC. Effects of sunscreen on skin cancer and photoaging. Photodermatol Photoimmunol Photomed. 2014;30(2-3):55-61. doi:10.1111/phpp.12109

2. Raffa RB, Pergolizzi JV Jr, Taylor R Jr, Kitzen JM; NEMA Research Group. Sunscreen bans: Coral reefs and skin cancer. J Clin Pharm Ther. 2019;44(1):134-139. doi:10.1111/jcpt.12778

While sunlight is beneficial for Vitamin D and mood, UV light can have various negative effects on skin like sunburn, aging, cancer and even immune suppression. UVB is the type that is responsible for the most skin damage on the surface, and is more intense in the summer and locations closer to the equator. This is in contrast to UVA light that is constant throughout each day and penetrates skin deeper. Both are responsible for aging and causing skin cancer. The amount to which UV rays can cause erythema/sunburn depends on the amount of exposure, skin type and thickness, intensity of the rays, and the amount of and ability to produce melanin. There are many risk factors in getting sunburn more easily like fairer skin, freckles, light eyes and many moles on the skin. These people should be more concerned with protecting themselves from the sun and its rays, but everyone should be applying sunscreen daily. Some ways to protect yourself including staying out of the sun, avoiding tanning beds and wearing protective clothing if outside. Sunglasses or hats are good for eye protection, considering the sun’s UV rays can cause ocular effects. The ultimate protection is daily sunscreen.