Skin Cancers
Skin cancer has reached epidemic proportions with estimates at 2-3 million new cases each year, with women under 45 years being most affected (Al-Dujaili, Henry, Dorizas & Sadick, 2017).
Many countries have implemented sun-smart health campaigns to protect the populations from skin cancers, yet the incidences are still rising. Such public health policies need to balance risks of sun exposure with the need for vitamin D (made in the skin from direct sun exposure) and its health benefits against many chronic diseases including cancer (Osiecki, 2012, p510).
Sunlight is made up from a spectrum of visible and non-visible radiations. Sunlight includes ultraviolet (UV) radiation of different types. UV-A, which comprises about 90% of the UV spectrum, can penetrate deep into the skin, but this causes premature skin aging, oxidative stress, and cell damage including skin cancers. UV-B light doesn't penetrate as deep into the skin, and is responsible for sunburn, premature aging, oxidative stress, and cancer initiation. However, UV-B is responsible for making vitamin D3 in the skin (Osiecki, 2012, p510).
The main types of skin cancers include the following (American Academy of Dermatology, 2017; Osiecki, 2012, p510):
The symptoms of skin cancers can include the following:
The risk factors of skin cancer include the following:
Many countries have implemented sun-smart health campaigns to protect the populations from skin cancers, yet the incidences are still rising. Such public health policies need to balance risks of sun exposure with the need for vitamin D (made in the skin from direct sun exposure) and its health benefits against many chronic diseases including cancer (Osiecki, 2012, p510).
Sunlight is made up from a spectrum of visible and non-visible radiations. Sunlight includes ultraviolet (UV) radiation of different types. UV-A, which comprises about 90% of the UV spectrum, can penetrate deep into the skin, but this causes premature skin aging, oxidative stress, and cell damage including skin cancers. UV-B light doesn't penetrate as deep into the skin, and is responsible for sunburn, premature aging, oxidative stress, and cancer initiation. However, UV-B is responsible for making vitamin D3 in the skin (Osiecki, 2012, p510).
The main types of skin cancers include the following (American Academy of Dermatology, 2017; Osiecki, 2012, p510):
- Actinic Keratoses - mainly present as dry, scaly patches or spots, and can be pre-cancerous growths. Often seen on people with fair skin, on parts of the body with a lot of sun exposure, and for those over 40 years of age.
- Basal cell carcinoma (BCC) - this is the most common type of skin cancer (at about 70% of all skin cancers), and often develops after years of frequent sun exposure or indoor tanning. They look like a pink or flesh-coloured smooth patch of skin, and can be found anywhere on the body.
- Squamous cell carcinoma (SCC) - this is the second most common type (20% of all skin cancers), also develops after frequent sun exposure on affected areas. These look like a red bump or scaly patch, or a sore that heals and re-opens again.
- Melanoma - frequently develops in a mole or suddenly appears as a new dark spot on the skin. Use the ABCDE method to identify a melanoma - they are Asymetrical (one half is unlike the other), have an irregular Border, a variable or shades of Colour, a Diameter of over 6mm, and Evolving or changing their size, shape or colour. Melanomas can also occur on skin areas not normally exposed to sunlight (Armstrong & Custa, 2017).
The symptoms of skin cancers can include the following:
- Crusty, non-healing sores
- Small skin lumps which can be red, pale or pearly in colour
- New darker spots, freckles or moles which may be changing in colour, thickness or shape over a period of weeks to months, especially if they are getting darker.
The risk factors of skin cancer include the following:
- Location – your place of residence on the planet - ie, the closer to the equator or atmospheric ozone depletion areas you are, the higher the risk (Osiecki, 2012, p511).
- Fair skin - and/or fair hair, or red hair with freckles (Osiecki, 2012, p511).
- Artificial tanning - the surge in indoor tanning centres in the 1980s lead to a dramatic increase in UV light exposure and all forms of skin cancer (Al-Dujaili, Henry, Dorizas & Sadick, 2017). Indoor tanning devices typically emit more UV-A light, hence the increase in skin cancer risk (Osiecki, 2012, p511).
- Smoking and alcohol - lifestyle factors such as smoking, and high alcohol consumption, especially white wine and other alcoholic liquor (Al-Dujaili, Henry, Dorizas & Sadick, 2017).
- Sun exposure - there are differences in how sun exposure may cause melanoma or the BCC/SCC skin cancers: melanomas are associated with brief but high intensity exposures to UV radiation, but BCC/SCC cancers result from high long-term UV radiation exposure (Armstrong & Custa, 2017).
- Vitamin D deficiency - ironically, a deficiency in vitamin D (levels <=20ng/mL) is linked to an increased incidence of skin (and other) cancers (Timerman et al., 2017).
- Medical procedures – transplant recipients have a higher risk, perhaps due to immune system suppression. Radiation therapy can cause metastatic skin cancers (Osiecki, 2012, p511).
- Sunscreen use -sunscreens are supposed to be protective against skin cancers, but actually the reverse has shown to be the case in scientific studies. This is because most sunscreens mainly block the UV-B light, which causes the redness and burning from sun exposure. Thus they give a false sense of security to people to stay out in the sun longer, to be exposed to more UV-A light, which is the form linked to melanomas. In addition, using a sunscreen with a SPF of 10 or lower provides very little UV-A protection and increase the risk of melanomas. Also, many sunscreens contain carcinogenic ingredients which can be absorbed into the skin (Westerdahl, Ingvar, Måsbäck & Olsson, 2000).
- Environmental chemicals – personal care products, deodorants, creams, makeup, and perfumes which come in contact with the skin are a potential risk. These products contain many synthetic chemicals, most of which are unregulated and not checked for safety. Parabens, found in shampoos and other personal and cleaning products, can increase the damaging effects of UV light (Al-Dujaili, Henry, Dorizas & Sadick, 2017).
- Toxic metals – exposure to arsenic from natural sources (water, air, soil or dietary intake), medicines, treated timber or other sources can cause oxidative stress, DNA damage, inactivation of tumour suppressor genes (which prevent cancer), and increased cell growth in some types of skin cancers (Chen & Olsen, 2016).
- Genetics – genetic mutations have been found in about 40% of people diagnosed with melanoma, to cause skin cancer in people at a younger age and without chronic sun damage to the skin (Armstrong & Custa, 2017). People with some forms of the MTHFR genetic mutation may have a higher risk of SCC (Osiecki, 2012, p511).