Lung cancer and smoking | How related are they?

Lung cancer and smoking | How related are they?

Studies have shown that small cell lung cancer, which is the most dangerous type, is associated with smoking. Does the association between lung cancer and smoking mean that all smokers should be affected?

The close relationship between lung cancer and smoking has caused the disease to increase dramatically, as a result of the increase in the number of people who smoke. The harmful chemicals in cigarette smoke not only affect the lungs, but they may cause at least 15 different types of cancer.

The relationship between lung cancer and smoking

The exact causes of lung cancer cannot usually be determined, but smoking is one of the factors that increase the risk of developing the disease. About 90% cases of lung cancer are linked to smoking, and tobacco causes the death of 22% cancer patients. Tobacco smoke contains nearly 7,000 chemicals, including 70 known carcinogens; Therefore, smoking is the most important preventable cause of lung cancer. 

Many people wonder about the relationship between lung cancer and smoking
What is the close relationship between lung cancer and cigarette smoking?

Lung cancer and smoking, despite the close relationship between them, does not necessarily mean that all smokers will be infected with the disease. In general, smokers are 15-30 times more likely to develop the disease than non-smokers.

In addition, the possibility of smokers contracting the disease is affected by several factors, the most important of which are the number of cigarettes a smoker consumes per day and the duration of continuation; Therefore, there is no safe limit to smoking, but it should be completely abstained from that habit as soon as possible. The sooner you stop smoking, the lower your risk of developing bLung Cancer.

How does smoking cause lung cancer?

When you inhale tobacco, thousands of harmful chemicals enter the lungs, affecting the DNA in all cells of the body and interfering with the way it works. Smoking can cause harm all over the body, but the damage often starts in the lungs. These substances first attack the cells lining the lungs and airways and cause damage to parts of the DNA that are responsible for protecting the body from cancer, leading to abnormalities in the cells.

At the same time, the body tries to repair the damage caused by the inhaled chemicals, but over time the damage builds up to a point where the body can no longer repair it, leading to the formation of cancer cells.

In addition, the effects of tobacco inhalation also extend and cause damage to the alveoli; They are the small air sacs in the lungs that are responsible for gas exchange. The alveoli carry oxygen into the blood and expel carbon dioxide out of the body during exhalation. Complications of damage to the alveoli include chronic obstructive pulmonary disease.

Types of lung cancer common in smokers

Lung cancer is divided into two basic types:

  • Small cell lung cancer - SCLC
  • Non-small cell lung cancer - NSCLC

80–85% lung cancer cases have NSCLC, according to to studiesWhile small cell lung cancer is the most dangerous type. Smoking increases the risk of both types, however, 951 TP2T cases of small cell lung cancer had a history of smoking. 

Non-small cell lung cancer can also be divided into several subtypes depending on where the tumor began to grow. The most important of these types are:

  • Adenocarcinoma: The growth of this tumor begins in the mucous cells lining the lungs, and it is the most common type in non-smokers, but it is still more prevalent in smokers than in non-smokers.
  • Squamous cell carcinoma: The tumor initially affects the cells lining the airways. It is less common than adenocarcinoma but is more commonly associated with smokers.

Lung cancer and passive smoking

The relationship between lung cancer and smoking is not limited to the smoker only, but the exposure of non-smokers, especially children, to tobacco smoke or what is known as passive smoking causes inhalation of many harmful substances and toxins that cause cancer.

A passive smoker can be exposed to the same risks as an actual smoker. Therefore, passive smoking increases the risk of several types of cancer, the most important of which is lung cancer. As with active smoking, the longer a person is exposed to secondhand smoke, the higher the risk of developing lung cancer.

There is a relationship between lung cancer and passive smoking because people who inhale cigarette smoke are exposed to the same risks as a smoker himself
Lung cancer and passive smoking - What is the effect of smoking on children?

Electronic cigarettes and cancer

Electronic cigarettes are devices that work using batteries to simulate the smoking process, as they are similar in use to some smoking behaviors, such as the movement of hands and mouth, but without the burning of tobacco. E-cigarettes deliver nicotine and some flavorings as a vapor or aerosol instead of smoke.

Although there is not enough research on this type of cigarette and its link to the development of lung cancer, according to the American Cancer Society, it does cause some carcinogenic substances to enter the body, but in smaller quantities than conventional cigarettes.

When the liquid in e-cigarettes is exposed to excessive heat, it produces formaldehyde, a cancer-causing chemical. Studies are still ongoing on other health risks associated with the use of these cigarettes, and non-smokers are never advised to use them.

Some flavors contain a chemical compound called diacetyl that may increase the risk of bronchiolitis, a serious lung problem.

Photo of a man using electronic cigarettes
Electronic cigarettes and their relationship to lung cancer

Some electronic cigarettes may transmit heavy metals, such as: lead and tin, and most of these cigarettes contain nicotine, which hinders mental development in adolescents and may also cause addiction. In addition, e-cigarette smokers have a number of chronic problems, the most important of which are:

  • Vomiting and nausea
  • Cough and chest pain
  • Unexplained weight loss
  • shortness of breath
  • Fatigue and fever

Symptoms of lung cancer in smokers

After knowing the close association between lung cancer and smoking, as well as lung cancer and passive smoking, the symptoms of infection should be known, because early diagnosis of the disease is one of the most important factors for successful treatment. are similar Lung cancer symptoms For smokers and non-smokers, including:

  • Chronic or coughing with blood or rusty sputum
  • Chest pain that worsens with deep breathing, coughing, or laughing
  • Hoarseness
  • Loss of appetite and weight
  • Feeling tired and exhausted
  • shortness of breath

You should remember that no matter how old you are, it's never too late. Stopping smoking at any time improves overall health and prevents further harm. Other than the association between lung cancer and smoking, smoking can cause many other diseases that may take the life of a smoker.
look at me Effect of smoking on oral and dental health.


  1. NIH
  2. The Lancet
  3. healthline
  4. Cancer Research UK
  5. Centers for Disease Control and Prevention

Common Questions

The risk of developing the disease increases with the number of cigarettes a smoker consumes and the number of years of smoking. In general, infection rates increase around the age of 40 and peak after the age of 70.

Lung function improves within one month after smoking cessation, and cilia regain normal function within 9 months, which relieves shortness of breath and coughing.

Abstaining from smoking improves the effectiveness of treatment, prevents further damage, and reduces the likelihood of tumor recurrence.

Smoking is not the only cause of infection. Other influencing factors include air pollution, genetics, and exposure to certain toxic substances.

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