Understanding Skin Cancer: Types, Risk Factors, and Prevention Strategies

04 April 2019

The skin is the largest organ of the human body and acts as a physical barrier and first line of defense against pathogens.

The skin has two layers: the epidermis and the dermis.

The epidermis is made of keratin, which protects against foreign substances. The dermis contains sweat glands and is followed by a layer of fat with blood vessels.

Type of Skin Cancer

Skin cancer can occur in any of these layers of skin, and the three main types of skin cancer are melanoma, squamous cell and basal cell skin cancer.

Melanoma

Melanoma is the most dangerous type of skin cancer, as it has the fastest growth rate. Melanocytes, which are the cells between the epidermis and the dermis, are responsible for producing melanin, which are pigments that affect the colour of the skin.

These pigments are made to protect our body from ultraviolet radiation from the sun. In melanoma, these melanocytes become cancerous. Once melanocytes become cancerous, they stop producing melanin and expose our body to harmful UV radiation. Cancerous cells continuously grow and divide indefinitely, and occupy space needed by other healthy cells, thereby restricting these cells from carrying out important tasks.

In the UK, the 6th most common cancer is melanoma, and women are statistically more likely to get melanoma than men. In the US alone, it is expected that over new 73,000 cases will be diagnosed in 2015. The number of melanoma cases is increasing over time as people get older and older.

Older people are more prone to melanoma and cancers in general due to the deterioration of cells. However, melanoma is one of the most common cancers in young adults as well and the public has to be aware of the dangers of melanoma.

Basal Cell Carcinoma

Basal cells are actually a special type of keratinocyte, found at the bottom of the epidermis, responsible for producing all the skin on the surface. Basal cell carcinoma (BCC) along with squamous cell carcinoma (SCC), are both skin cancers which develop in the epidermis.

However, BCC takes up 75% of non-melanoma skin cancer cases, whereas SCC only takes up 20%. The remaining 5% are taken up by rarer skin cancer types, such as Kaposi’s sarcoma, Merkel cell carcinoma, and T cell lymphoma skin cancers.

Squamous Cell Carcinoma

Squamous cell carcinoma (SCC) is also a type of non-melanoma skin cancer that develops in the epidermis. It takes up 20% of non-melanoma skin cancer cases, whereas BCC takes up 75%.

The remaining 5% are taken up by rarer skin cancer types, such as Kaposi’s sarcoma, Merkel cell carcinoma, and T cell lymphoma skin cancers.

Factors

Ultraviolet Light

The number one factor that increases the risk of developing skin cancers is simply ultraviolet light. Ultraviolet light or radiation comes from either the sun or sunbeds and is the main cause of all skin cancers. Exposure to direct sunlight regularly increases the chances of attaining all three main types of skin cancer. This is hard to avoid for those living in regions with hotter climates near the equator.

Skin Tone and Type

One major factor affecting the chances of getting skin cancers is the individual’s skin tone and type. According to the American Cancer Society, white individuals are 20 times more likely to attain skin cancer compared to African Americans. Despite popular belief, darker skin people do not actually have more melanocytes than those with paler skin. Everybody has the same amount. Darker skin only indicates that they have more active melanocytes, producing more pigments. This is necessary for those living in areas with more exposure to sunlight.

Sunburns and Use of Sunscreen

Furthermore, sunburns and the use of sunscreen affect developing melanoma. This goes hand in hand with the previous point, individuals with lighter skin tones are easily sunburnt and thus this increases the risk of developing melanoma. Individuals who do not use sunscreen when going to areas with direct sunlight for long periods of time are more likely to be sunburnt and therefore develop skin cancers.

Family History

If the individual has more than 2 family members who have had skin cancers, then they are prone to get it as well.

Other Factors

Other factors that increase the chances of attaining skin cancer include getting an organ transplant and having already had previous cases of skin cancer. Lastly, the higher the number of moles an individual has, the more likely they are to develop skin cancer.

Skin Cancer Symptoms

Melanoma Signs and Symptoms

Symptoms of melanoma are usually unusual new growth of moles or a change in an already existing mole.

Basal Cell Carcinoma Signs and Symptoms

Basal cell skin cancer appears as waxy, shiny, white lumps or a scaly patch on areas of the body. These moles usually have irregular borders, change colours, grow in diameter, and are not asymmetrical.

Both basal cell and squamous cell skin cancers generally occur in areas of the body that are exposed to the sun.

Ultimately, if you do find any irregularities on your skin, visit your GP as soon as possible. Melanoma and squamous cell skin cancer are best treated in the early stages. Keep in mind that basal cell is a slower-growing skin cancer and may take even years to develop. Biopsies are when specialists take a sample of the skin to check whether the affected area has cancer or not.

Squamous Cell Carcinoma Signs and Symptoms

Squamous cell cancer symptoms usually appear as a patch, a pink lump or an ulcer on the skin.

Treatment

Doctors use a staging system for all cancers called the TNM system.

T stands for the size and depth of the tumour, N is whether it has spread to other nodes, and M is whether the cancer has reached other parts of the body. Each letter has 4 stages, and the higher the stage, the later the cancer was diagnosed.

At the earliest stage, Stage 0, the cancer has only started developing. It is called Bowen’s disease. Stage 0 means that it is only on the surface of the skin. The earlier the cancer is diagnosed, the better the chance of survival.

The most common treatment for skin cancer is surgery. It means physically removing the mole and the skin area surrounding it. Radiotherapy is administered to patients after cancer removal, and is also an alternative treatment if surgery is not feasible for any reason. Finally, chemotherapy may also be considered, particularly for later stages of melanoma.

2 to 4 visits for the subsequent year may be necessary for stage 1 to 2 treatments. Keep track of any more changes in the skin area. Stage 4 is when the cancer is advanced and has metastasized, meaning it has spread to other parts of the body. When this occurs, the cancer is no longer curable. Consult your doctor and nurses for treatments to suppress the cancer as much as possible. Make sure you talk to others about your feelings and seek professional help if needed, as this is a very traumatising situation.

Prevention of Skin Cancer

Stay Indoors Between 11am-3pm

To minimise exposure to direct sunlight, it is recommended that you spend time indoors between 11 a.m. and 3 p.m. During these hours, the sun's rays are the strongest and can cause the most damage to your skin.

Wear Protective Clothing

When you are in the sun, make sure to wear clothes that cover your skin. This will help protect you from harmful UV radiation. In addition, always remember that sunbeds are not a safe alternative to natural sunlight, as they also emit UV radiation.

Use Sunscreen

Using sunscreen is one of the most effective ways to protect your skin from the sun's harmful rays. Make sure to use sunscreen with at least 15 SPF when going outside. Look for symbols indicating the quality of the sunscreen. Sunscreen is vital for the protection of your skin and can really help prevent your cells from being damaged.

Check Your Skin Regularly

It is important to check your skin regularly for any changes. If you notice any new growths or changes in existing moles, visit your GP as soon as possible. Melanoma and squamous cell skin cancer are best treated during the early stages.