Description of the condition
Skin cancer is a term that includes both melanoma and keratinocyte cancer. Keratinocyte cancer (also known as non-melanoma skin cancer) generally refers to basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), although it also includes other rare cutaneous neoplasms (Madan 2010). Skin cancer is the most common cancer in populations of predominantly fair-skinned people (Donaldson 2011; Lomas 2012; Stern 2010), with incidence increasing (Garbe 2009; Leiter 2012). There are variations in annual incidence rates between these populations, with Australia reporting the highest rate of skin cancer in the world (Lomas 2012). In 2012, the estimated age-standardised incidence rate for melanoma was almost 63 per 100,000 people for Australian men, and 40 per 100,000 people for Australian women (AIHW 2012). In Europe, incidence rates range from 10 to 15 per 100,000 people (Garbe 2009; Lasithiotakis 2006), with rates highest amongst men (Stang 2006). In the United States, incidence rates are approximately 18 per 100,000 people (Garbe 2009), with the highest rates reported for women (Bradford 2010). Keratinocyte cancer is much more common than melanoma. In 2012, the estimated Australian age-standardised rates for BCC and SCC were 884 and 387 per 100,000 people, respectively (Staples 2006). The cumulative three-year risk of developing a subsequent keratinocyte cancer is 18% for SCC and 44% for BCC (Marcil 2000).
Melanoma is the most fatal form of skin cancer. In 2007, the melanoma mortality rate was 8.9 and 3.5 per 100,000 people for Australian men and women, respectively (AIHW 2012). In 2003, Finland reported mortality rates of 0.8 per 100,000 people for both men and women (Stang 2006). Amongst non-Hispanic whites in the United States, mortality was 1.7 per 100,000 people for those aged under 65 years (Linos 2009). Generally, mortality rates of skin cancer have been stabilising or declining (Cohn-Cedermark 2000; Giles 1996; Jemal 2008), although this trend appears to be happening for women but not for men (Giles 1996; Jemal 2008; Stang 2006; Thompson 2005) or older people (Linos 2009). Survival rates from melanoma have been improving (Thompson 2005), with five-year survival in the United States and 10-year survival in Germany both approximately 80% (Leiter 2012; Singh 2003), and over 90% for young American adults (Reed 2012). High survival rates and improvements in melanoma mortality rates are likely to be due to improvements in early detection and treatment (Chapman 2011; Garbe 2009; Giles 1996). Keratinocyte cancer, by contrast with melanoma, is less fatal yet can cause disfigurement, often on visible areas of the body (English 1997). It is the most common cause of hospitalisations for cancer, accounting for 11% of all inpatient cancer hospitalisations in Australia (AIHW 2012). For individuals, keratinocyte cancer can cause impairment, financial strain, and distress (Burdon-Jones 2010; Leiter 2008). For the healthcare system, skin cancer is one of the most costly cancer groups (Housman 2003), with keratinocyte cancer the driving force behind high costs. While melanoma cost the Australian health system 30 million Australian$ between 2000 and 2001, keratinocyte cancer cost 264 million Australian$ (AIHW 2005). In the United States, keratinocyte cancer is estimated to cost over 450 million US$ per year (Chen 2001).
Risk factors for skin cancer include genotype (an individual's genetic makeup); phenotype (the body's expression of that genotype), both of which determine an individual's predisposition to skin cancer; and environmental factors. The primary environmental risk factor is exposure to ultraviolet (UV) radiation from the sun (IARC 1992; Kricker 2007; Madan 2010; Ramos 2004). Melanoma and BCC appear to be associated with intermittent and childhood sun exposure, whereas SCC appears to be related to constant, cumulative sun exposure (Gallagher 2010). While genotype, phenotype, and ambient UV exposure cannot be altered, individuals have considerable control over their sun protection behaviours.
Cancer authorities recommend five adjunctive methods of sun protection, in addition to avoiding peak UV sun wherever possible:
wear sun-protective clothing;
wear sun-safe hats;
apply broad-spectrum, water-resistant, SPF 30+ sunscreen to sun-exposed skin; and
wear sun-protective sunglasses (Cancer Council Australia 2013).
These methods have been shown to be effective. In the case of sunscreen, correct usage during childhood is thought to reduce lifetime skin cancer risk by 78% (Stern 1986); daily usage can prevent development of melanoma and SCC; and in the long-term, it may also protect against BCC (Green 1999; Green 2011; Van der Pols 2006). Recent in vivo studies have shown that correct application of SPF 30+ sunscreen can prevent all three cancer types (Hacker 2013). However, each of the adjunctive methods of sun protection encompass several elements, which can make the behaviour, and measuring the behaviour, complex.
Despite these challenges, evidence suggests that interventions aimed at improving people's sun protection behaviours can work. The sustainability of such programmes, however, is less clear. In Australia, despite years of sun protection programmes, improvements in these behaviours appear to have stabilised or worsened (Green 2013; Livingston 2007; Markin 2013). This decrease may be due in part to concerns about potential negative consequences from low serum 25(OH)-vitamin D concentrations. Ultraviolet radiation exposure is required for vitamin D synthesis, and low serum concentrations, which have been associated with growth retardation and skeletal deformation in children, and osteoporosis, cancers, autoimmune diseases, infectious diseases, and cardiovascular disease in adults (Holick 2007), may result from sun protection behaviours (Matsuoka 1987). Unclear or unbalanced messages regarding the vitamin D benefits and the skin cancer risks of sun exposure may also lead to confusion regarding the required level of sun protection (Hiom 2006; Langbecker 2011).
Description of the intervention
As described by Welsh 2011, education involves more than simply providing information, aiming to integrate knowledge, improve self-management, and produce behaviour change. Health education can include 'training', and consequently it is necessary to distinguish between education, which focuses on imparting knowledge and developing understanding, and training, which focuses on the development of skills (Michie 2011).
Interventions to reduce UV exposure are diverse and difficult to classify (Saraiya 2004). Interventions may use various media (e.g. posters, television and radio, and internet) and target multiple audiences (e.g. parents, children, high-risk groups, and healthcare providers) using multiple strategies (e.g. individuals, communities, and populations) in multiple contexts and settings (e.g. schools, healthcare settings, and recreational areas).
For the purposes of this review, we defined education as an intervention to provide information on (a) skin cancer, (b) its causes, (c) its consequences, or (d) how it can be prevented. Based on the definition by Wolf 2002, such interventions may use any instructional strategy or combination of strategies (e.g. problem solving, role-playing, videotapes, computer-assisted instruction, or booklets). These interventions may be delivered to the individual, via group sessions or through general media, including online and social media. Interventions can be targeted at the general population or specific high-risk groups (e.g. outdoor workers).
Education interventions can address different levels of prevention, although this review will only consider primary prevention programmes.
The aim of the intervention is to reduce the risk of skin cancer by informing people how to minimise UV radiation exposure.
Secondary prevention, which is not the subject of this review, is an intervention that aims to increase appropriate healthcare service use in response to signs of skin cancer (e.g. recognise skin changes and seek early diagnosis and treatment) and reduce the risk of reoccurrence or further development of skin cancer (Spratt 1981).
How the intervention might work
Educational interventions aim to change sun-protective behaviour by informing people of the severity and consequences of skin cancer (e.g. death), the risk factors associated with skin cancer (e.g. exposure to direct sunlight during the peak sun hours and use of solaria), and which protective behaviours to perform (e.g. wearing sunscreen that contains UVA and UVB protection and wearing hats and other protective clothing while in the sun). Thus, in addition to providing sufficient knowledge of potential dangers to warrant action, education programmes also offer guidance on efficacious actions to reduce the health threat if they are to successfully change health behaviours.
Specific components of primary education interventions (WHO 2012) may affect behaviour change by:
reinforcing basic information about skin cancer to embed understanding;
emphasising adherence to UV-protective behaviours; and
emphasising the importance of avoiding environmental triggers.
The logic model developed by the review authors (Figure 1) shows how educational programmes may influence skin cancer prevention outcomes.
Why it is important to do this review
Despite strategies and efforts to prevent skin cancer, a recent review highlighted the need for further research to improve skin cancer prevention (Lomas 2012). The incidence of both melanoma and keratinocyte cancer has increased dramatically over previous decades (Garbe 2009; Leiter 2012). Although melanoma is less common than keratinocyte cancer, it is more serious than other types of skin cancer and causes a large majority of skin cancer deaths (AIHW 2012). Both melanoma and keratinocyte cancer contribute to the high cancer-related health system costs (AIHW 2005; Chen 2001; Housman 2003).
There is an existing Cochrane review examining non-education interventions (e.g. use of topical therapies, retinoids, antioxidants, dietary modifications, and complementary therapies) for preventing keratinocyte cancer in people at high risk of developing these cancers (Bath-Hextall 2007). Elsewhere, there are reviews of the use of education programmes for primary-care physicians (Goulart 2011) and interventions to prevent skin cancer by reducing exposure to ultraviolet radiation (Saraiya 2004), which found evidence that education and policy interventions increase sun-protective behaviours in primary school and in tourism or recreational settings. Research findings in other settings provided insufficient evidence to warrant recommending specific interventions. Despite these limitations, educational programmes are commonly used in an effort to prevent skin cancer.
This proposed review will attempt to evaluate the effectiveness of educational programmes to prevent skin cancer, providing much needed evidence to guide governmental and community organisations acting in this field.