Skin Cancer: a Public Health Approach

Skin Cancer: A Public Health Approach

Skin Cancer: A Public Health Approach

Allison J. Erickson

Skin cancer is the most commonly diagnosed cancer in the United States, Australia, and the United Kingdom (Rouhani et al., 2009). Within this cancer, there are several types. These types include basal and squamous cell carcinomas, or keratinocyte cancers, as well as melanoma cancer. The American Cancer Society (ACS) (2012) says, “About 8 out of 10 skin cancers are basal cell carcinomas.” The remaining two out of 10 cancers are squamous cell carcinomas. Out of these two cancers, squamous cell tends to be more aggressive (ACS, 2012). Melanoma cancer accounts for less than five percent of diagnosed skin cancer, but results in the leading cause of skin cancer deaths (ACS, 2012). Recent estimates indicate that the incidences of melanoma have been rising over the last 30 years. “About 76,250 new melanomas will be diagnosed (about 44,250 in men and 32,000 in women),” suggests the ACS (2012). Rouhani et al. (2009) show that over one million non-melanoma skin cancers were diagnosed in 2008. In comparison with skin cancer risk 80 years ago, Volkovova, Bilanicova, Bartonova, Letasiova, and Dusinska (2010), share that the lifetime risk of melanoma was one in 500 persons. In 2000, the risk of melanoma was one in 75 persons. Through a public health approach, researchers are finding data, resources, and educational tools to help recognize and reduce the risks of skin cancer. With the help of governmental regulations and advocacy, skin cancers prevalence in this country and abroad are becoming more well-known and understood.

From a biological standpoint, in order to understand the different kinds of skin cancer, one must look at the biological characteristics of cancer, in general. As defined by (2012), “Cancer is a term used for diseases in which abnormal cells divide without control and are able to invade other tissues.” Cells are the basis to human life and, when working properly and effectively, grow and divide keeping the body healthy. However, when cancer infects a certain area of the body, the DNA of the cell becomes mutated, resulting in the damage of normal cell reproduction. This mass reproduction of damaged cells, results in the development of a tumor. Tumors are defined as being either malignant or benign. In order for a cancer tumor to be defined as benign, the mutated cells must remain in the original location of development, also said to be non-invasive. If the cells become invasive, moving to other parts of the body or lymph nodes, then they are defined as malignant (Rediscovering Biology, 2012). Whether a tumor is benign or malignant, there are five different types of tumors: carcinomas, sarcomas, leukemia, lymphoma, and myelomas. Skin cancer can fall into the category of either type of tumor.

One of the most influential environmental factors that aids in the process of damaging epidermal cells is UVB radiation. The World Health Organization’s (WHO) and the International Agency for Research on Cancer (IARC) reports that, “UVB is a complete carcinogen that is absorbed by DNA and can directly damage DNA” (IARC Working Group Reports, 2005, p. 7). The damage done by UVB radiation specifically mutates thymine and cytosine basis in DNA replication. As stated by Volkovova et al., (2010),

The radiation excited DNA molecules in skin cells, causing aberrant covalent bonds between adjacent cytosine bases by producing a dimer. During DNA replication, DNA polymerase incorporates an incorrect base opposite to an aberrant base, causing a mutation. The mutation caused by direct DNA damage can lead to skin cancers.

Researchers indicate that the majority of melanoma cases are the result of indirect UVB exposure (Volkovova et al., 2010). Once cells in the layers of skin start to become damaged, then tumors may begin to form in the skin.

Melanoma is caused by damage to skin cells called melanocytes. Melanocytes give skin its pigmentation and protect harmful effects of the sun in the deeper layers of the skin (ACS, 2012). Many individuals are currently living with benign melanocytic tumors on the skin, known as moles. The majority of moles are harmless, but having them increases the risk for developing melanoma.

Research has also indicated that approximately five to ten percent of melanoma cases occur because of hereditary predisposition. This hereditary predisposition has been linked to chromosome 9 with germline mutations in CDKN2A gene (Volkovova et al., 2010). “The risk of melanoma in CDKN2A mutation carriers varies between populations and is higher in regions with high sun exposure and high incidence of melanoma in the general population” (Volkovova et al., 2010). A small number of individuals may also have a predisposition to melanoma with a mutation on gene CDK4.

Although melanoma is the most deadly form of skin cancer, it is not the most prevalent. Basal cell and squamous cell carcinoma are the most common forms of keratinocyte cancer. Keratinocyte cells are the most abundant cell in the skin. When seen under a microscope, keratinocyte carcinomas show the same physical characteristics of these cells. The ACS (2012) says that 80 percent of the skin cancers reported is basal cell carcinomas and few are reported as squamous cell carcinomas. Increases in UVB exposure damages these cells and can turn into malignant cancer if left untreated. Usually, these damaged cells will move to nearby fatty tissue beneath the skin or to nearby lymph nodes.

Other forms of non-melanoma skin cancers that are not as common include: Merkel cell carcinoma, Kaposi sarcoma (KS), cutaneous lymphoma, and skin adnexal tumors. Merkel cell carcinoma develops from, “neuroendocrine cells (hormone-making cells that resemble nerve cells in some ways) in the skin” (ACS, 2012). This form of cancer often spreads to lymph nodes nearby and to internal organs. Development of Merkel cell is due in part to sun exposure, but having a common virus known as Merkel cell polymovirus (MCV) can also aid in the development. Small amounts of people living with MCV see changes in the virus’ DNA, which leads to this form of cancer. KS is developed within the dermis, but can be found in internal organs. Recently, KS has been seen in people with human immunodeficiency virus (HIV). This connection between HIV and KS is, “closely linked to the CD4 count … a measure of the effect of HIV on the immune system” (ACS, 2012). Because of this direct relationship, KS is considered an AIDS defining illness. “This means that when KS occurs in someone infected with HIV, that person officially has AIDS” (ACS, 2012). Other sarcomas of the skin develop in connective tissue cells, typically in the deep tissue of the skin. Some of these cancers include dermatofibrosarcoma protuberans (DFSP) and angiosarcoma, which is a blood vessel cancer.

Continuing, there are certain pre-cancerous and pre-invasive skin conditions that may lead to the development of skin cancer. Actinic keratosis, also known as solar keratosis, occurs from overexposure of sun rays. The keratoses are less than a quarter across and appear as rough, pink, red, or flesh colored spots on the skin (ACS, 2012). They are typically found on the face, ears, back of the hands, and arms of people with fair skin. Actinic keratosis does not cause any symptoms and go away on their own. However, these keratoses are known to come back numerous times. Another pre-cancerous disease is squamous cell carcinoma in situ, or Bowen disease. This is the earliest form of squamous skin cell cancer. The term “in situ” means that the, “cells of these cancers are still entirely within the epidermis and have not invaded the dermis” (ACS, 2012). Similar to Actinic keratosis, overexposure to the sun is a major risk factor.

As stated prior, there are tumors of the skin that are benign tumors, like moles. Other forms of these benign tumors include: Seborrheic keratoses, hemangiomas, lipomas, and warts. Seborrheic keratoses are raised spots with a tan, brown, or black appearance and have a waxy or rough surface. These keratoses appear on the skin’s surface. Hemangiomas are, “benign blood vessel growths often called strawberry spots or port wine stains” (ACS, 2012). Lipomas are fat cell growths, typically soft in nature. Lastly, warts are caused by a virus and appear as rough-surfaced growths on the skin.

Skin cancers are similar to many other cancers in that they develop due to damaging DNA replication in cells. Ultraviolet radiation, especially UVB, is primarily responsible for the damage of these cells. However, there are links to genetic mutations that can predisposition the likelihood of being diagnosed with skin cancer. Melanoma is less likely to be diagnosed than other skin cancers, but it is the most deadly. Other skin cancers, like basal and squamous cell carcinomas, are the most diagnosed and affect multiple layers of the skin. Continued monitoring by a doctor or dermatologist, as well as limiting sun exposure, is the most effective ways for preventing any type of skin cancer from occurring or reoccurring.

Moving forward, from an epidemiological approach, Mar, Wolfe, and Kelly (2011) indicate that Australia has the “highest incidence of skin cancer in the world, with a lifetime risk for invasive melanoma now 1 in 14 for men and 1 in 22 for women to age 55.” As stated earlier, not only is the probability growing in Australia, but also worldwide. Populations that see the highest number of skin cancer incidence are those with light skin. “The risk of melanoma…is much higher for individuals with red or fair skin that freckles or burns easily,” (Callister, Galtry, & Didham, 2011). Also, the lifetime risk of being diagnosed with melanoma is one in 50 for whites, one in 1,000 in blacks, and one in 200 for Hispanics (ACS, 2012). Caucasians are at a higher risk for skin cancer because of the low amounts of melanin in the skin. The higher the melanin, the darker color of skin one has (ACS, 2012). Gender also plays a factor in determining risk for skin cancer. “Men are two times more likely as women to have basal cell cancers and about three times as likely to have squamous cell cancers of the skin” (ACS, 2012). The age at which skin cancer is diagnosed spans across generations. A recent study in Olmsted County, Minnesota, concluded that the number of diagnosed young adults with melanoma is increasing (Reed et al., 2012). Although the number of young adults diagnosed is increasing, Reed et al. (2012) indicates that mortality from the disease is decreasing. Nevertheless, risks of getting skin cancer do grow larger as people get older (ACS, 2012).

One of the most well-known risks for all types of skin cancer is UV radiation exposure. Green, Wallingford, and McBride (2011), suggest that skin cancer risk can be reduced by educating and reducing sun exposure in the first two decades of a child’s life. In the 1990s, a case-controlled study in Belgium, Germany, and France showed that melanoma risk in adulthood rose with the levels of UV exposure in childhood (Green et al., 2011). Rouhani et al., (2009) conducted a survey involving 19 Palm Beach County schools to evaluate the amount of sun protection and education among eight to 11 year olds. Demographics included whites, blacks, and Hispanics. Results revealed that 51.4 percent of students never or rarely wear sunscreen greater than 15 SPF. Also, the knowledge of skin cancer was found to be relatively low (Rouhani et al., 2009). Likewise, Volkovova et al., share, “An increased risk of melanoma was seen with increasing number of sunburns for all ages, not just childhood. The magnitude of risk for five sunburns per decade was shown to be highest for adults and lifetime sunburns” (2012). Although applying sunscreen is highly recommended by health professionals, the ACS says, “…if you stay in the sun a long time, you are at risk of developing skin cancer even if you have put on sunscreen” (2012). That statement is an indication that sun exposure should be limited to reduce risks of skin cancer.

Correspondingly, the 1980s through present day have shown increasing popularity with the use of tanning beds (Fears et al., 2011). “Tanning bed use has been linked with an increased risk of melanoma, especially if it is stared before the age of 30” (ACS, 2012). The tanning industry has made claims that using artificial UV light helps increase Vitamin D levels. However, the ACS (2012) indicates that doctors are not sure what an optimal level of Vitamin D is and suggest that tanning beds should not be used to increase its levels. “Many studies indicate a significantly increased risk of cutaneous melanoma subsequent to sunburn/sunlamp exposure, especially among individuals who are young, Caucasian, and female. A European study showed that 40 hours of sun bed use resulted in a 55% increased risk for melanoma” (Volkovova et al., 2012). In their report studying the attitudes of school aged children and sun protection, Rouhani et al., (2009), reported that girls are more likely to try and get a tan, as well as saying that people who are tan look healthier. These perceptions are a growing concern for health professionals across the world, but are used to the advantage of tanning bed companies.

Other risk factors for developing skin cancer are similar with other cancers. These risk factors include previous skin cancer, exposure to certain chemicals, smoking, bearing moles, and a family history of skin cancer. The risk of skin cancer is increased if a first degree relative (father, mother, brother, sister) has had melanoma. “Around 10% of all people with melanoma have a family history of the disease” (ACS, 2012). Geneticists have indicated, also, that gene mutations are found in anywhere from 10 to 40 percent with high melanoma rates (ACS, 2012). Moles are considered benign melanocytic tumors and may never cause problems, but one with many moles is more likely to develop melanoma than one with few or none.

Prevention of skin cancer can be done in numerous ways. First, the ACS (2012) encourages highly susceptible people to limit UV exposure, but if in the sun, to wear a hat and sunglasses, sun protectant clothing, and SPF sunscreen of 30 or more as recommended by the American Academy of Dermatology. These actions should be taken on both sunny and cloudy days as UV light exposure can still be strong. Sunscreen should be continually applied at lease every two hours, but should not be an excuse to continue to stay in the sun.Likewise, one should seek shade often. Parents should also protect their children from the sun, especially children under six months of age. Avoiding tanning beds and sunlamps will greatly reduce the risk for long term skin damage, particularly at a younger age. One with a high mole count should watch for abnormal mole development. Abnormal development would include changes in shape, size, and texture. If there is a change, one should consult with a doctor or dermatologist sooner than later. For individuals with a history of familial skin cancer, there is genetic counseling and testing to evaluate the risk of gene mutation. Avoiding harmful chemicals, like arsenic, can also reduce the risk of skin cancer. Lastly, ceasing from tobacco use can reduce risks of all types of skin cancer, especially on the lips.

When evaluating the statistical methods used by researchers in determining skin cancer risks and occurrences, various methods are shown to be successful. Many of these methods have to do with increasing the education about exposure to ultraviolet (UV) radiation. In the study conducted by Roberts and Black (2009) the research focused on the effectiveness of two interventions to help in reducing the amount of UV exposure in college students. These participants were from two private universities in the Midwestern part of the United States and evaluated during spring break in March. Both universities were similar in demographic, latitude, and size. This sample included 73% being female with an average age of 20.6 years old. All participants planned trips to warmer climates for spring break. Because individuals with fair skin, red hair, and freckles are more predisposition to burn easily, increasing the risk for skin cancer (Callister, Galtry, & Didham, 2011), the skin type of participants was measured, “as the sum of 9 items regarding eye color, hair color, skin color, freckle presence, responses to sun exposure, and skin sensitivity, with higher values indicating darker skin type” (Roberts & Black, 2009). Before leaving for spring break, the participants were given statements based on the Skin Cancer Attitudes and Beliefs (SCAB) scale. The scales ranged from agreeing or disagreeing with statements like, “’There is a chance I will get skin cancer if I am not careful’ and ‘My skin won’t age so fast if I reduce my sun exposure’” (Roberts & Black, 2009). In addition, researchers used the Stages of Change model to assess the readiness to change sun exposure behaviors of the participants. Along with the methods mentioned, Roberts and Black (2009) asked participants to record their sun exposure while on spring break. Within the diaries, participants wrote down how likely they were wearing a hat, applying sunscreen of 15 or greater, and when they were in the sun most often using a five point Likert-scale; one being never, five being always. The purpose of such an extensive study was to determine appropriate interventions for educating college students about sun safety during spring break and over the summer months. The results indicated that after educating the participants about safe exposure to UV radiation, students reported higher scores on sun protection benefits using the SCAB scale. Also, the majority of students’ Stage of Change responses increased from precontemplation to contemplation or preparation phase for increasing sun safety behaviors.