Skin Cancer Prevention

Introduction

Your skin suffers damage when exposed to sunlight for a long time or intense sunlight for a short time. The body then replaces these damaged cells through a carefully controlled process of cell replacement. When control of this process is lost, cells multiply uncontrollably, piling up and causing skin cancer.

Cancer cells attack and damage nearby healthy tissues and can spread to distant body parts. This process is called metastasis and is the source of the name metastatic cancer.

Cancer statistics: a few observations

Globally, an estimated 20 million new cases of cancer and 9.7 million deaths caused by cancer occurred in 2022, with these cases including non-melanoma skin cancers.¹ An estimated one in five people develop cancer in a lifetime, with one in nine people assigned male at birth (AMAB) and one in 12 people assigned female at birth (AFAB) dying from the disease.¹ Lung cancer is the most frequently diagnosed cancer worldwide, followed by breast cancer.¹

Nearly half (49.2%) of all cancer cases and over half (56.1%) of global cancer deaths in 2022 occurred in Asia, where 59.2% of the world’s population lives.¹ 

Skin cancer is also common worldwide. In 2022, 331,647 new cases of melanoma were reported globally, leading to 58,645 deaths.¹ Melanoma occurs more frequently among people AMAB.²

Skin cancer

The two key sub-types of skin cancer are:

• Melanomas occur in cutaneous melanocytes (the cells that produce the pigment, melanin) in the deepest parts of your skin
• Non-melanomas occur in the top layer of your skin. The most frequent types of non-melanoma skin cancer are basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) 

Causes

Cancer is caused by the DNA in cells undergoing mutation (a change in the DNA sequence). Mutations can arise from inherited or environmental factors. Environmental factors include:³

• Radiation exposure
• Ultraviolet light exposure
• Alcohol consumption
• Air pollution
• Cigarette smoking
• Food
• Infectious diseases

Signs and symptoms

The general symptoms of cancer can include: 

• Fatigue (severe tiredness)
• Unexplained fever
• Unexplained weight loss
• Muscle and joint pains
• Lumps or swellings
• Unexplained bleeding or bruising

The symptoms associated with skin cancer are:⁴

• A mole that has changed in terms of size, shape, or colour
• A new growth
• A sore that does not heal
• A sore that has not healed within four weeks
• A sore that is itchy or one that hurts, bleeds, or crusts for longer than four weeks 

Development of cancer

Mutations

Cancer develops because of mutations (i.e. changes) in your DNA. Your DNA carries instructions for your cells to function, grow and divide. DNA can be seen as the code that runs your cells, the way computer code runs a computer. Sometimes, DNA gives erroneous instructions due to changes within its code. This is called a mutation and results in:

• A rapid growth of cells, producing new cells that have similar mutations
• An uncontrolled growth of cells, causing cells to pile up and lead to cancer
• The DNA of repair genes is unable to make corrections so more cells duplicate with cancerous anomalies

Free radicals

Ultraviolet (UV) rays cause melanoma and non-melanoma cancers by inducing the formation of free radicals in the skin. 

Free radicals are atoms, molecules, or ions with an uneven number of electrons and always search for one more electron to pair with. These free radicals are highly reactive, unstable, and short-lived.⁵

The reason why they are so dangerous is because they cause chemical reactions in our bodies and damage cell structures by taking electrons away from them. It stabilises the free radicals but damages our cells while doing so and the damage they cause takes a long time to repair.⁶

Skin cells form reactive oxygen species (a subset of free radicals) regularly due to exposure to UV light. When more reactive oxygen species (ROS) form than antioxidant defense systems can eliminate, oxidative stress occurs. It is this oxidative stress that causes diseases.

The oxidative stress can be reduced by:

• Lowering exposure to UV light
• Increasing levels of antioxidants to scavenge ROS

We get antioxidants from fruits and vegetables of various colours. A few examples are: 

• Vitamins C and E 
• Copper
• Zinc
• Selenium 

Risk factors

We all face similar environments, yet only a few of us develop cancer. This is due to many reasons beyond our control. However, knowing some of the risk factors that predispose us to cancer can help our awareness and proactivity with cancer prevention. Some of the risk factors include the following.

Age

Cancer can develop at any age but individuals who are 65 years or older have a greater chance of developing cancer.

Lifestyle

Drinking alcohol and smoking are habits that make individuals susceptible to cancer.

Exposure to sun radiation

Exposure to the sun for long periods or short durations of intense exposure to the sun can cause cancer.

Family history/genetics

If cancer runs in your family, you have a chance of inheriting the cancer mutation in your genes.

Diseases and viruses

Some health conditions can increase the likelihood of developing certain types of cancer. For example, individuals with a diagnosis of ulcerative colitis are likely to develop colorectal cancers. The same can be said for viruses. Here are a list of viruses that can lead to cancer:

• Human papillomaviruses (HPVs)
• Epstein-Barr virus (EBV)
• Hepatitis B virus (HBV)
• Hepatitis C virus (HCV)
• Human immunodeficiency virus (HIV)
• Human herpes virus 8 (HHV-8)
• Human T-lymphotropic virus-1 (HTLV-1)
• Merkel cell polymavirus (MCV)

Environment

You have an increased chance of developing cancer if you:

• Smoke cigarettes
• Live with a smoker
• Work in a chemical factory dealing with cancer-causing chemicals like asbestos or benzene

Prevention of skin cancer

Reduce excessive sun exposure

UV rays from the sun can increase your risk of skin cancer. Sun exposure can be minimised by: 

• Being in the shade. Whenever your shadow is shorter than your height, do not go into the sun as the UV rays are strongest then and are likely to cause harm
• Covering your skin with UV-protective clothes, wearing a wide-brimmed hat, or using an umbrella 
• Applying sunscreen 20-30 minutes before sun exposure and re-applying it after 90 minutes. If you are participating in water activities, it should be applied more frequently

The SPF (sun protection factor) recommended by dermatologists is 30, as it blocks 97% of UVB radiation and delays damage.

Ultraviolet light and its significance

The UV light that the sun emits is of three types: UVA, UVB, and UVC. 

Ninety-five percent of UVA radiation reaches the Earth and penetrates the skin, where it damages DNA and forms free radicals. UVA causes tanning, penetrates glass and clouds, and is present throughout the year. The wavelength of UVA rays is 320 to 400 nanometres (1 nanometre is 1 billionth of a metre) which makes it more penetrating and less harmful than UVB rays.

UVB rays are responsible for sunburn. They have a wavelength of 290-320 nanometres and are associated with skin cancer. UVB rays damage the DNA of cells.

UVC is the third type of rays that have the potential to be more damaging than either UVA or UVB. With a wavelength of 100-280 nanometers, UVC is the shortest and most intense wavelength of UV. However, UVC rays are completely absorbed by the ozone layer and hence do not cause cancer. 

Nutrition

We should eat raw fruits and vegetables more often as they contain nutrients (vitamins and minerals) that protect us from many diseases. 

Certain by-products of reactions occurring within our body and exposure to radiation produce free radicals which damage parts of our cells like DNA, lipids, and proteins. Our body requires a balance between free radicals and antioxidants to protect us from many diseases, including cancer.

Phytochemicals are compounds produced by plants.⁷ These substances are present in fruits and vegetables and protect our cells. Phytochemicals prevent cancer by:

• Stopping carcinogens from attacking our cells
• Helping cells stop cancer-like changes

Some phytochemicals and antioxidants that prevent cancer include vitamins C and E, beta-carotenes, retinoids, and green tea:⁶

Vitamin C

Vitamin C is present in all citrus fruits as well as sprouts, broccoli, and bell peppers. It helps in collagen formation, protects against UVA and UVB radiation, corrects pigmentation issues and reduces skin inflammation.

Vitamin E

Exposure to UV rays depletes vitamin E in the body, which causes oxidative stress. Vitamin E has skin-stabilising properties and is an essential ingredient in food, such as green leafy vegetables, almonds, and sunflower seeds.

Beta carotenes

Beta carotenes are also called oral sun protectants. They are present in all red, orange, and yellow-coloured fruits and vegetables. They are also in greens like coriander, spinach, and kale.

Retinoids

Retinol is a type of retinoid used in cosmetics for skin rejuvenation and anti-ageing. It is a vitamin A-based skincare product.

Green tea

Polyphenols are present in green tea. Their topical application prevents the action of UV rays. They are also present in ginger, oats, and broccoli. These essential ingredients are best available in fresh fruits and vegetables.

Skin cancer outcomes

Skin cancers are largely preventable if we make a few changes to our lifestyle and diet, such as applying sunscreen and eating more fruits and vegetables. We must observe our skin and be attentive to the changes. Early diagnosis is most important in improving skin cancer outcomes.

FAQs

Why is skin important?

Your skin is the largest organ of your body. It regulates our body temperature and protects us from injuries and invasions of disease-causing microorganisms. It is also our first line of defense against harmful sun radiation. It does many things for us so we should take good care of our skin with sunscreen.

What are the layers of the skin?

The epidermis is the thin, top layer of skin, and the dermis is the middle layer and is much thicker. Finally, the hypodermis is the fatty, bottom layer of the skin. 

What are carcinogens?

Carcinogens are cancer-causing substances that can be found in tobacco, asbestos, and benzene. Radiations like UV light also cause cancer. 

Is skin cancer fatal?

Our genetics, exposure to UV rays, and nutrition govern our susceptibility to developing skin cancers. Not all skin cancers are fatal if diagnosed early.

Summary

• The two main types of skin cancer are melanomas and non-melanomas. They arise from different cells in the skin
• Most skin cancers occur because of exposure to UV radiation from the sun and altered lifestyle and nutrition
• The radiation alters cell structures and mechanisms occurring within the cell 
• To overcome the harmful effects, we should:
  • wear protective clothing and sunglasses
  • apply sunscreen
  • eat a healthy diet 
  • exercise regularly 
• A healthy diet contains fruits and vegetables (of different colours) packed with vitamins, minerals, and antioxidants. A few examples are green leafy vegetables, green tea, berries, lemons, beans and broccoli
• Prevention and early detection are key so it’s best to be aware of all risk factors that could increase your chances of developing skin cancer