**4. Photoprotective behaviors**

Acute UVR exposure has deleterious effects on the skin, and contributes to the cumulative effects of lifetime UV exposure. Cellular damage and DNA mutations caused by UVR, if not repaired, can accumulate in the skin and contribute to skin aging and increase skin cancer risk. Melanomas typically develop in areas of the skin that are occasionally exposed to sunlight, while non-melanomas tend to develop in areas of the skin that are frequently exposed to sunlight [19]. Therefore, it is important to protect all areas of skin from UVR by practicing a combination of photoprotective behaviors. The most common form of sun protection that comes to mind is sunscreen, but it is not the only method. Comprehensive sun protection programs endorsed by healthcare professionals include the use of broad spectrum sunscreen, wearing protective clothing, staying in the shade and limiting sun exposure especially at times of peak intensity (10am-2pm), and avoiding indoor tanning devices [8, 9, 24]. Sand, water, and snow reflect UV rays, so protective measures should be taken seriously when in these environments[19]. These core photoprotective methods should be followed by all people regardless of skin color and FST, and especially followed by susceptible populations. However, only 60.6% of adults surveyed in the United States in 2010 reported that they usually or always follow at least one photoprotective behavior when spending time outdoors [25].

Wearing protective clothing means that the clothing should be a physical barrier to sunlight, and should cover as much of the body as possible. Protective clothing includes wearing long pants or a long skirt, and long sleeves. Hats that shade the face, neck and ears are part of protective clothing. Most men wear a baseball cap for protection, but these caps do not shade the face, neck, and ears as well as a wide-brimmed hat that offers more coverage [25]. Sunglasses also fall under protective clothing as they protect the eyes and areas around the eyes from UVR and reduce the risk of developing ocular melanoma. The best protec‐ tion against solar UVR would be obtained by through a combination of protective cloth‐ ing and sunscreen [26].

regions with light-skinned populations such as Australia, Switzerland, and Ireland [2], and that the highest registered incidence of melanoma is found in Australia (Geller et.al, 2012). There is a 20 times greater incidence of malignant melanoma in Caucasians than in African-Americans in the United States [19]. One reason for this difference is that darkly pigmented skin responds to UVR differently than light pigmented skin. In African-Americans, DNA damage is not prominent below the epidermis, and damaged skin cells are more likely to undergo apoptosis. It is believed that the melanin in more highly pigmented individuals provides a higher level of protection than in light skinned individuals. By absorbing UV light, melanin is protective, but it is not enough to give 100% protection, so more highly pigmented

people are still prone to UV-induced skin damage and can still get skin cancer [23].

number sunburns experienced during childhood and adolescence [6, 17].

**4. Photoprotective behaviors**

214 Highlights in Skin Cancer

The effects of UV damage on the skin are cumulative. The total number of severe sunburn incidences and lifetime dose of UVR are important factors to consider when determining skin cancer susceptibility. Outdoor workers have a greater risk of developing SCC than indoor workers because their skin experiences chronic irradiation with solar UV. Spending long periods of time outdoors for recreational purposes is associated with increased risk of melanoma [17]. Major risk factors for developing melanoma are the number of nevi and

Acute UVR exposure has deleterious effects on the skin, and contributes to the cumulative effects of lifetime UV exposure. Cellular damage and DNA mutations caused by UVR, if not repaired, can accumulate in the skin and contribute to skin aging and increase skin cancer risk. Melanomas typically develop in areas of the skin that are occasionally exposed to sunlight, while non-melanomas tend to develop in areas of the skin that are frequently exposed to sunlight [19]. Therefore, it is important to protect all areas of skin from UVR by practicing a combination of photoprotective behaviors. The most common form of sun protection that comes to mind is sunscreen, but it is not the only method. Comprehensive sun protection programs endorsed by healthcare professionals include the use of broad spectrum sunscreen, wearing protective clothing, staying in the shade and limiting sun exposure especially at times of peak intensity (10am-2pm), and avoiding indoor tanning devices [8, 9, 24]. Sand, water, and snow reflect UV rays, so protective measures should be taken seriously when in these environments[19]. These core photoprotective methods should be followed by all people regardless of skin color and FST, and especially followed by susceptible populations. However, only 60.6% of adults surveyed in the United States in 2010 reported that they usually or always

follow at least one photoprotective behavior when spending time outdoors [25].

Wearing protective clothing means that the clothing should be a physical barrier to sunlight, and should cover as much of the body as possible. Protective clothing includes wearing long pants or a long skirt, and long sleeves. Hats that shade the face, neck and ears are part of protective clothing. Most men wear a baseball cap for protection, but these caps do not shade the face, neck, and ears as well as a wide-brimmed hat that offers more coverage

Consumers are advised to select sunscreens that offer broad spectrum (UVA and UVB) protection with a sun protective factor (SPF) of 15 or greater by the United States Food and Drug Administration (FDA) [1]. Sunscreens are applied directly onto the skin and they reduce UVR penetration by reflection or absorption [9]. Broad spectrum sunscreens can protect against UV-induced erythema and immunosuppression [21]. Sunscreen use is a method of chemoprevention, meaning it can suppress or prevent the progression of premalignant skin lesions into cancer [19]. Sunscreen with SPF of 15 or greater reduces skin cancer risk, and prevents both melanoma and non-melanoma skin cancers [24]. The amount of protection is related to the SPF level and the amount of sunscreen applied. Lower SPF sunscreens are less effective, especially when applied inadequately, than higher SPF sunscreens [27].

Consistent daily application of sunscreen is especially recommended for individuals who are more susceptible to developing melanoma [19]. Consistent long-term daily application of broad spectrum sunscreen to the head and arms was shown to decrease the incidence of malignant melanoma compared to discretionary sunscreen use in a randomized controlled prospective study of Australians [28]. Fewer melanocytic nevi develop on Caucasian children who routinely used SPF 30 broad spectrum sunscreen when going outdoors for more than 30 minutes than children who do not use sunscreen [29]. Sunscreen itself is safe and does not increase the risk of skin cancer. Meta-analysis of 11 case-control studies did not find an association between sunscreen use and increased risk of developing melanoma [30]. Some studies have reported an association between topical sunscreen use and melanoma, but this relationship is probably connected to inappropriate and compensatory use of sunscreen.

The compensation hypothesis is that people tend to wear less protective clothing and/or prolong the amount of time spent in the sun when they use higher SPF sunscreens. This compensatory behavior actually defeats the purpose of using sunscreen, and it increases risk of skin cancer because the risk of sunburn is increased [1, 17, 24]. In an observational study of European sunbathers, it was found that the duration of time spent sunbathing was up to 25% longer for those who used SPF 30 than those who used SPF 10 [31]. Sunscreen is meant to be used as an adjunct to other methods of photoprotection and not to extend the amount of intentional sun exposure time. Consumers generally have a false sense of security when wearing high SPF sunscreens, especially those of SPF of 50 and greater, and they often forgo other methods of photoprotection, such as wearing protective clothing. Interestingly, the consumers who wear sunscreen and spend more time sunbathing are generally those who are more sensitive to UVR. This likely explains why the incidence of melanoma continues to increase despite more people wearing sunscreen [26].

Another behavior that compromises the effectiveness of sunscreen is inadequate sunscreen application thickness. Sunscreen accumulates in fissures on the skin, so it is necessary to apply enough product to fill in the fissures and to fully cover epidermal ridges [32]. Most consumers apply sunscreen below the standard thickness used for the international SPF test, which is 2 mg/cm2 [1]. Consumers apply between 0.5 and 1.2 mg/cm2 sunscreen and consequently do not receive the expected amount of sun protection. The actual SPF of the sunscreen can be decreased by 20-50% compared to the rated SPF when it is applied improperly [19, 27, 32]. The reduction of actual SPF as a function of application thickness was recently demonstrated during a study in which Chinese women applied SPF 4,15, 30, or 55 sunscreen at 0.5, 1, 1.5, or 2 mg/cm2 . The actual SPF was calculated for each individual after exposure to solar simulated UVR. It was determined that at the standard application thickness of 2 mg/cm2 the observed SPF was similar to the rated SPF. However, as application thickness decreased there was an observed linear decrease in actual SPF for SPF 4 and 15 sunscreens, and an exponential decrease in the actual SPF for the SPF 30 and 55 sunscreens [27]. Inadequate application of lower SPF sunscreens may put consumers at greater risk of sunburn and skin cancer than inadequate application of higher SPF sunscreens.

been in a tanning bed [19]. The age at which people start using indoor tanning technolo‐ gies is a risk factor for developing skin cancer as well. The lifetime risk of developing melanoma is 75% higher in people who first use indoor tanning beds before the age of 35 [35]. Younger people have a greater tendency to use indoor tanning devices, possibly because of the social perception that having a tan is attractive. More people between the ages of 18-24 used indoor tanning devices than people over the age of 25 in 2010. In both age groups, females exposed themselves to artificial UVR to obtain a tan more than males did. Most of these adults were non-Hispanic whites [25]. The high skin cancer risk associated with indoor tanning coupled with the addictiveness of the behavior has caused many states in the U.S. to pass laws restricting the use of indoor tanning devices by minors in 2012 [19].

Skin Cancer Prevention Strategies http://dx.doi.org/10.5772/55241 217

Consumers should be aware of their skin's reaction to sunlight when they are outdoors, and take appropriate action when noticing adverse reactions to sun exposure. Regardless of sunscreen application and whether sun exposure is intentional or unintentional, if the skin becomes red (indicative of cellular damage) and uncomfortable at any time it is prudent to immediately find shade and put on protective clothing [26]. Parents should be vigilant of signs of redness in their childrens' skin as well. Infants and children should be kept in the shade out of direct sunlight [2]. Self-examination of skin for suspicious growths and nevi is also recom‐

Chemoprevention is the use of natural or synthetic agents to prevent or reverse the develop‐ ment of cancer [21]. Sunscreen use is considered a form of chemoprevention because it contains compounds, such as avobenzone and octyl salicylate, that inhibit UVR from damaging the skin. Supplementation of sunscreens with various phytochemicals and antioxidants has been shown to improve the function of sunscreens in preventing photodamage [13]. Oral intake of certain vitamins, antioxidants, and plant extracts can provide systemic protection as well.

A diet rich in fruits and vegetables has generally been associated with lowering the risk of a variety of diseases and cancers, including skin cancer. Regular consumption of fruits and vegetables was associated with a decreased risk of SCC in a dietary study of 1360 adults in Nambour, Australia. In this study it was also found that a diet high in meat and fat was positively associated with the development of SCC but not BCC [36]. Fruits and vegeta‐ bles contain bioactive phytochemicals, such as flavonoids, polyphenols and carotenoids. These compounds can boost antioxidant and immune system defenses in the body, including in the skin [37]. Carotenoids and flavonoids naturally protect plants from solar UVR, and consumption of these phytochemicals can provide systemic photoprotection for humans [8]. Polyphenols from tea have been shown to protect against UVB-induced contact sensitization, inflammation, carcinogen-induced cancer of the skin, lung, and esophagus in

mended for early detection of skin cancer [2, 17].

rodent models [37].

**phytochemicals, and vitamin supplementation**

**5. Chemoprevention with topical and dietary antioxidants,**

To compensate for inadequate application thickness, the American Academy of Dermatol‐ ogy recommends using a minimum of SPF 30 sunscreen, which is higher than the FDA's recommendation of 15. High SPF sunscreen should especially be used when going outdoors on days when the UV index is predicted to be high and there is greater risk of overexpo‐ sure. Spending even 45 minutes outdoors unprotected on a day of moderate UV index value can cause skin damage [33]. One application of sunscreen may not be enough if an individual stays outdoors for long periods of time and/or is involved in activities that cause the skin to perspire or get wet.

Proper use of sunscreen includes reapplication every two hours, and more frequently when sweating, swimming, or towel drying [24]. It is important to reapply sunscreen because the active components may become unstable and lose activity during exposure to sunlight [27]. The FDA does not currently require a photostability test for sunscreens [1]. The duration of water resistance is limited, so water resistant sunscreens need to be reapplied frequently when swimming or sweating [24]. It is required by USFDA monograph that the duration of water resistance (40 or 80 minutes) be indicated on the label to instruct consumers about when they should reapply the sunscreen [1]. Spray on sunscreen is thought to be less effective than traditional sunscreens because it is not rubbed directly onto the skin. The FDA is currently investigating the effectiveness of spray on sunscreens, and is performing inhalation safety testing as well [24].

Indoor tanning is a popular alternative to natural tanning because it can be done at any time of the year, but it is actually very dangerous because the skin is intentionally exposed to intense UVR repeatedly over short periods of time. Tanning bulbs emit predominantly UVA, which is known to cause high levels of oxidative stress in the skin and contribute to greater risk of melanoma [26]. They also emit a small amount of UVB that primarily damages the DNA in skin cells during indoor tanning sessions. Artificial UVR from indoor tanning equipment is considered to be carcinogenic along with solar UVR, yet approximate‐ ly 28 million people expose themselves to it annually in the United States [34].The likelihood of developing SCC is 2.5 times greater for people who use tanning beds, and the likeli‐ hood of developing BCC is 1.5 times greater [35]. Individuals who have ever used tanning beds have a 15% greater risk of developing melanoma than individuals who have never

been in a tanning bed [19]. The age at which people start using indoor tanning technolo‐ gies is a risk factor for developing skin cancer as well. The lifetime risk of developing melanoma is 75% higher in people who first use indoor tanning beds before the age of 35 [35]. Younger people have a greater tendency to use indoor tanning devices, possibly because of the social perception that having a tan is attractive. More people between the ages of 18-24 used indoor tanning devices than people over the age of 25 in 2010. In both age groups, females exposed themselves to artificial UVR to obtain a tan more than males did. Most of these adults were non-Hispanic whites [25]. The high skin cancer risk associated with indoor tanning coupled with the addictiveness of the behavior has caused many states in the U.S. to pass laws restricting the use of indoor tanning devices by minors in 2012 [19].

mg/cm2 [1]. Consumers apply between 0.5 and 1.2 mg/cm2

application of higher SPF sunscreens.

the skin to perspire or get wet.

testing as well [24].

2 mg/cm2

216 Highlights in Skin Cancer

receive the expected amount of sun protection. The actual SPF of the sunscreen can be decreased by 20-50% compared to the rated SPF when it is applied improperly [19, 27, 32]. The reduction of actual SPF as a function of application thickness was recently demonstrated during a study in which Chinese women applied SPF 4,15, 30, or 55 sunscreen at 0.5, 1, 1.5, or

SPF was similar to the rated SPF. However, as application thickness decreased there was an observed linear decrease in actual SPF for SPF 4 and 15 sunscreens, and an exponential decrease in the actual SPF for the SPF 30 and 55 sunscreens [27]. Inadequate application of lower SPF sunscreens may put consumers at greater risk of sunburn and skin cancer than inadequate

To compensate for inadequate application thickness, the American Academy of Dermatol‐ ogy recommends using a minimum of SPF 30 sunscreen, which is higher than the FDA's recommendation of 15. High SPF sunscreen should especially be used when going outdoors on days when the UV index is predicted to be high and there is greater risk of overexpo‐ sure. Spending even 45 minutes outdoors unprotected on a day of moderate UV index value can cause skin damage [33]. One application of sunscreen may not be enough if an individual stays outdoors for long periods of time and/or is involved in activities that cause

Proper use of sunscreen includes reapplication every two hours, and more frequently when sweating, swimming, or towel drying [24]. It is important to reapply sunscreen because the active components may become unstable and lose activity during exposure to sunlight [27]. The FDA does not currently require a photostability test for sunscreens [1]. The duration of water resistance is limited, so water resistant sunscreens need to be reapplied frequently when swimming or sweating [24]. It is required by USFDA monograph that the duration of water resistance (40 or 80 minutes) be indicated on the label to instruct consumers about when they should reapply the sunscreen [1]. Spray on sunscreen is thought to be less effective than traditional sunscreens because it is not rubbed directly onto the skin. The FDA is currently investigating the effectiveness of spray on sunscreens, and is performing inhalation safety

Indoor tanning is a popular alternative to natural tanning because it can be done at any time of the year, but it is actually very dangerous because the skin is intentionally exposed to intense UVR repeatedly over short periods of time. Tanning bulbs emit predominantly UVA, which is known to cause high levels of oxidative stress in the skin and contribute to greater risk of melanoma [26]. They also emit a small amount of UVB that primarily damages the DNA in skin cells during indoor tanning sessions. Artificial UVR from indoor tanning equipment is considered to be carcinogenic along with solar UVR, yet approximate‐ ly 28 million people expose themselves to it annually in the United States [34].The likelihood of developing SCC is 2.5 times greater for people who use tanning beds, and the likeli‐ hood of developing BCC is 1.5 times greater [35]. Individuals who have ever used tanning beds have a 15% greater risk of developing melanoma than individuals who have never

UVR. It was determined that at the standard application thickness of 2 mg/cm2

. The actual SPF was calculated for each individual after exposure to solar simulated

sunscreen and consequently do not

the observed

Consumers should be aware of their skin's reaction to sunlight when they are outdoors, and take appropriate action when noticing adverse reactions to sun exposure. Regardless of sunscreen application and whether sun exposure is intentional or unintentional, if the skin becomes red (indicative of cellular damage) and uncomfortable at any time it is prudent to immediately find shade and put on protective clothing [26]. Parents should be vigilant of signs of redness in their childrens' skin as well. Infants and children should be kept in the shade out of direct sunlight [2]. Self-examination of skin for suspicious growths and nevi is also recom‐ mended for early detection of skin cancer [2, 17].
