Skin Cancer is the most common type of cancer in the world 1. Ultraviolet (UV) Radiation exposure is one of the major causes of melanoma and Non-melanoma Skin Cancer (NMSC), such as basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) 2-3.
UV radiation is emitted naturally from the sun. Some of the sun’s radiation is absorbed by the earth atmosphere and a small part reaches the earth’s surface. A long-term exposure to solar light (UV radiation) can damage the DNA inside your skin. This can cause cells to start growing out of control in the epidermis, leading to the formation of a cluster of abnormal cells called “cancerous cells”4-5. This is the start of skin cancer.
In order to protect the skin from UV radiation, there are widely available products (creams oils, gels, sprays) that when applied over the skin, filter UV rays. These products are known as Sunscreen and are made in a broad range of Sun Protection Factors (SPF). The SPF is a measurement of how much solar energy is required to create sunburn on the protected skin. The number is not related to the time but to the amount of solar exposure, and this depends on the time of the day and the geographic location. As the SPF value increases, sunburn protection increases as well 6. Amount of UVB filtered by the Sunscreen according to SPF Value7
Some studies have shown that the use of sunscreen reduces the incidence of NMSC 8-10. However, the effectiveness of sunscreen in preventing skin cancer depends on different aspects. It depends not only on the SPF and the resulting UV spectral absorption but also on the amount of sunscreen applied to the skin as well as how well the sun-exposed parts of the skin are covered. Reapplication also has a large effect on the efficacy of sunscreen 11.
According to the Food and Drug Administration (FDA), the amount of sunscreen in the form of cream or oil applied to achieve the corresponding SPF rating should be 2mg (0.4 teaspoons) per cm2 area (circa the area of an average thumb’s nail). In order to achieve full protection, apply the right amount of sunscreen and cover the entire exposed area of skin properly. Also apply sunscreen to all exposed areas of the skin followed by 20-30 min in the shade in order to allow the protective film to regenerate. It is recommended that sunscreen be reapplied every two hours, as well as after swimming, playing and or exercising outdoors, in order to achieve the highest protection of all exposed areas 11.
Use sunscreens wisely!
Written by Mireya Achaerandio.
- Lomas A, et al. A systematic review of worldwide incidence of non-melanoma skin cancer. Br J Dermatol 2012; 166: 1069–1080.
- Griffin LL, et al. Non-melanoma skin cancer. Clin Med (Lond). 2016; 16(1): 62–65.
- Scherer D, et al. Genetics of pigmentation in skin cancer – A review. Mutat. Res. 2010; 705: 141– 153.
- National Cancer Institute [NCI Dictionary of Cancer Terms: Skin Cancer]. Retrieved from https://www.cancer.gov/publications/dictionaries/cancer–terms/def/skin–cancer
- Sarnoff, DS. (2019, February). Skin Cancer Foundation [Skin Cancer: Basall cell carcioma]. Retrieved from https://www.skincancer.org/skin-cancer-information
- US Food and Drug Administration (July 2017). [Sunscreen: How to Help Protect Your Skin from the Sun]. Retrieved from https://www.fda.gov/drugs/understanding–over–countermedicines/sunscreen–how–help–protect–your–skin–sun
- Americal Cancer Society (July 2019). [How do I protect Myself from Ultraviolet (UV) Rays?]. Retrieved from: https://www.cancer.org/healthy/be–safe–in–sun/uv–protection.html
- Green, A.C, et al. Daily sunscreen application and betacarotene supplementation in prevention of basal-cell and squamous-cell carcinomas of the skin: A randomized controlled trial. Lancet. 1999; 354: 723–729.
- Van Der Pols, J.C, et al. Prolonged Prevention of Squamous Cell Carcinoma of the Skin by Regular Sunscreen Use. Cancer Epidemiol. Biomark. 2006; 15: 2546–2548.
- Ulrich C, et al. E. Prevention of non-melanoma skin cancer in organ transplant patients by regular use of a sunscreen: A 24 month, prospective, case-control study. Br. J. Dermatol. 2009; 16: 78–84.
- Perugini P, et al. Topical sunscreen application preventing skin cancer: systematic review. Cosmetics. 2019; 6 (42):1-13.
Evidence of positive effect of Sunscreens in preventing NMSC
|(Study) Green A.C, et al. Lancet 1999, 354, 723-729. (Follow-up) Van Der Pols J.C. et al. Cancer Epidemiol. Biomark. Prev. 2006, 15, 2546-2548.||Australia. 1621 participants. Age 20–69||sunscreen SPF 15 plus + 30mg betacarotene sunscreen SPF 15 plus placebo tables betacarotente only placebo only (Control Group)||No difference between group 12 and between groups 3-4. The incidence of SCC was reduced in the group using sunscreen. It was detected a prevention action in SCC when sunscreen was applied daily.|
|Ulrich C. et al. Br. J. Dermatol. 2009, 161, 78-84.||Berlin, Germany. 120 participants, immunocompromised organ transplant. Age 40–77||(1) sunscreen SPF 50 plus education (teaching how to correctly apply the suncream) (2) sunscreen SPF 50 selfresponsible application (control group)||Significantly less lesions were detected in the sunscreen group with previous education (89 lesions) when compared to the other group (273 lesions).|