Skin Cancer And Smoking

Overview

Unlike normal cells that multiply in a regular and controlled way, cancer cells multiply uncontrollably and continue to pile.

Melanoma of the skin is the seventeenth most prevalent cancer worldwide.¹ It is often challenging to diagnose non-melanoma skin cancers because they occur in many subtypes. Non-melanomas remain undiagnosed because most get treated with surgery or ablation.

Smoking

The smoking of tobacco can be active (when you smoke yourself) or passive (when someone near you smokes). Tobacco has nicotine. When chewed or smoked, it exerts its harmful effects. Tobacco smoke has several toxic agents that damage our skin.

Toxic effects of smoking

Our skin is exposed to several toxic agents every day, and smoking ages the skin. The exact mechanism for it is not known. A few theories are as follows.²

• The heat from cigarettes burns the skin
• There occurs a change in elastic fibres
• Vasoconstriction is the narrowing of blood vessels. It reduces the blood supply to the skin, alters elastic fibres, and collagen loss
• It even reduces moisture in the skin

Besides cancer smoking causes many other types of skin problems they are⁴

• Psoriasis
• Delayed healing of wounds
• Premature ageing
• Alopecia
• Acne
• Lupus erythematosus

Skin cancers

Skin cancer can be melanoma and non-melanoma.

Basal cell carcinoma arises from the basal layer of the epidermis, and squamous cell carcinoma arises from the uncontrolled multiplication of epidermal cells. Basal cell carcinoma appears as a nodule lying superficial on the pigmented skin. Squamous cell carcinoma presents as hard raised borders or a wounded skin area.³

Effects of sunlight on skin

Exposure to sunlight causes vitamin D formation in the skin. Excessive exposure to UV radiation is the single important reason for developing skin cancer. The ultraviolet radiations are a combination of UVA, UVB, and UVC.

UVA 95% of radiations that reach the earth. They penetrate deep into the skin and cause tanning of the skin. They induce indirect DNA damage by forming free radicals. They have longer wavelengths and more penetrating power.

UVB, the sunburn rays cause more damage by causing cancer than UVA. They have wavelengths of 290-320 nanometres.

The 3rd type is the UVC. They are more damaging than UVA and UVB. The ozone layer absorbs UVC rays. Since they do not reach Earth they do not cause any harm to the skin.³

Effects of tobacco

Cigarettes, e-cigarettes, cigars, and pipes use tobacco. The heated tobacco products produce aerosols that have nicotine, which is highly addictive. Aerosol also contains flavoured, non-tobacco additives. Some additives are not present in nicotine, but other carcinogens are present in heated tobacco products.

Electronic cigarettes are popular these days. These cigarettes use electronic nicotine delivery systems (ENDS) and non-nicotine delivery systems (ENNDS). The use of ENDS and ENNDS is called vaping. ENDS not only contains nicotine in varying amounts but also toxic emissions.⁵

Smoking and skin cancer

Cigarette smoke contains a large number of chemicals; 69 of them are believed to be cancer-causing or carcinogenic. These and other chemicals prevent our bodies from fighting cancer.⁷

Smoking weakens our body’s immune system.

It interferes with our body’s capacity to kill cancer cells.

It damages the DNA of cells; when such a cell grows, the cancer grows.

Development of cancer

Oxidative stress theory in skin cancer 

Skin is the largest organ in the human body. It faces rigours by air pollutants, UV rays, cosmetics, smoke, and drugs every day. Oxygen causes aerobic respiration in human cells. 95% of oxygen provides energy and becomes water. The remaining 5% produces substances called reactive oxygen species (ROS).⁶

These ROS (reactive oxygen species) cause skin ageing and inflammation. The various types of ROS are superoxide(O2-), hydrogen peroxide (H2O2), hydroxyl radical (OH1-), and nitric oxide (NO).

These ROS form molecules, atoms, and ions with unpaired electrons. They are free radicals. Skin cells face reactive oxygen species due to UV light. Under normal circumstances, the body can fight stress on its own. When more reactive oxygen species (ROS) form than the antioxidant defense, oxidative stress occurs, which harms the cells of our body.

Free radicals are a natural part of life. So, we are never rid of them. But we can minimise their exposure and effects. These free radicals act upon the biomolecules like DNA, lipids, and proteins. They take electrons from these biomolecules to damage them but stabilise themselves by accepting electrons from them. These free radicals survive for a very short time but have a long-lasting impact on biomolecules. It takes even weeks to months to years to recover from their effects.

Antioxidants are molecules that like to share and donate an electron to a free radical and remain stable. It helps to stabilise free radicals by neutralising, delaying, or preventing further damage from the oxidation process. Antioxidants can be natural or artificial. Oxidants that the body produces are known as endogenous antioxidants. Those that come from outside the body are called exogenous.

Exogenous antioxidants are vitamins A, C, E, lycopene, selenium, manganese, flavonoids, and polyphenols. Antioxidants are from plants, fruits, and vegetables. Different antioxidants have different roles, so it is essential to eat a varied diet.

Oxidative stress causes diseases like heart disease, cancer, arthritis, stroke, respiratory diseases, Parkinsonism, and other inflammatory or ischemic conditions.

Oxidative stress

 occurs due to several activities and processes

• Excessive exercises
• Tissue trauma
• Ischemia
• Smoking
• Environmental pollution
• Exposure to radiations

The oxidative stress on the skin can be reduced by

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

Mutations

Exposure to ultraviolet light causes skin cancer and smoking enhances its effects.

Cancer develops because of mutations in DNA. DNA carries codes that help cells to function, grow, and divide. Errors occurring in this code cause cells to change.⁸ A mutation or change in cell code causes-

• Cells divide abnormally into large numbers
• Changes in the cell codes turn off the suppressor genes that regulate the number of cells formed. As a result, cells multiply uncontrollably and pile
• Mutations even turn off genes. Genes, that correct errors in the DNA of cells when inhibited cause uncontrolled growth

Changes in a few genes can not cause cancer alone.⁸ Cancer occurs when many other genes also mutate. For example, when genes that control body weight mutate, they cause obesity and overweight people are likely to acquire cancer more. So more complex changes in genes are required.

Gene variations are common. We all have them. Their cumulative effect of changes in many such genes influences our cancer risk.

How does quitting smoking affect us?

Tobacco is smoked in cigarettes, pipes, and cigars and even chewed. It causes narrowing of blood vessels, staining of skin, and wrinkles. 

Blood circulation and heart rate improve on quitting smoking. As blood circulation improves more oxygen and nutrients reach the skin making it healthy.

Quitting smoking can have beneficial results. Depression, pain, anxiety, and side effects of cancer treatment, pose difficulty in quitting smoking.

FAQ

Does smoking increase the risk of cancer?

Yes, smoking increases the risk of cancer. Many types of oral cancers occur in smokers namely oral leukoplakia, and cancers of the lips.

Are skin cancer and smoking linked?

Persistent smokers have an increased risk of squamous cell carcinoma.

Does smoking change the skin?

• Smoking causes the skin to change
• Wrinkles are visible
• Skin colour changes
• It becomes coarse

Does cancer occur even after quitting smoking?

After quitting smoking, the risk of cancer decreases. However, one has a chance of getting cancer compared to those who have never smoked.

Summary

Carcinogenic substances in tobacco damage the DNA of cells and cause mutations. These mutations disrupt control over activities within the cell and lead to uncontrolled growth. Over time, genetic changes occur within the cells causing cancer. The International Agency for Research of Cancer warns tobacco smoking and chewing can cause cancer in the human body. 

Exposure to excessive sun radiation or intense radiation for a short time causes skin cancer. Ultraviolet radiation is the single most important cause of skin cancer. They produce free radicals that damage cell structure.

To prevent skin cancer

• quit smoking 
• reduce exposure to ultraviolet radiation 
• having a healthy diet
• do plenty of exercises.