Lung cancer: causes, symptoms and prevention

Lung cancer is the most common type of cancer in the world: 2 million cases are diagnosed annually. Of these, many are avoidable.

Every year 2 million new cases of lung cancer are diagnosed in the world , becoming not only the most frequent, but also the one that causes the most deaths.

In fact, lung cancer is responsible for more deaths than colon, prostate and breast cancer combined. The reason for its high mortality is that it affects the functionality of the lungs, which are the vital organs responsible for both capturing oxygen for the entire body and eliminating carbon dioxide, which is toxic.

We know that smoking is behind most cases of lung cancer, although it continues to baffle scientists as it can also appear in people who have never smoked.

Therefore, in today’s article we will review the nature of lung cancer , detailing both its causes and the most common symptoms, as well as the ways to prevent its appearance, the techniques to diagnose it and the available treatments.

What is lung cancer?

All cancer consists of an abnormal and uncontrolled growth of the cells of our own organism , which, due to a mutation in their genetic material, lose the ability to properly coordinate and regulate their division cycles.

When they grow more than they should, a tumor is formed, which can be benign if it does not cause damage and / or does not spread to other places, or it can be malignant. In case it compromises the viability of the organ in which it is located, we speak of cancer.

Lung cancer is any malignant tumor that begins in the cells of the bronchi, extensions of the trachea that penetrate the lungs and are responsible for making air reach the alveoli, the small sacs where gas exchange occurs. .

It is the most common type of cancer in the world since the cells of the bronchi are continuously exposed to pollutants in the environment, which can act as carcinogens, that is, increasing the chances that lung cells suffer mutations that lead to these tumor growths.

In addition, it is also the most lethal since the lungs are vital organs for the entire body to receive oxygen and eliminate carbon dioxide. That this functionality is lost due to a tumor puts the life of the person in serious danger, as it compromises the viability of all the organs and tissues of the body.

Lung cancer is more common in smokers and usually appears in older adults. Not many cases are usually diagnosed before 45 years of age.


As we already know, cigarette smoking is behind most cases of lung cancer, especially in active smokers, although passive smokers are also at higher risk of developing it at some point in their life. In fact, between 80% and 90% of lung cancers appear in smokers.

The more cigarettes you smoke each day and the earlier you start smoking, the greater the likelihood that you will develop lung cancer in adulthood. And this is so because tobacco smoke is full of carcinogenic substances.

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Inside a cigarette there are more than 7,000 different chemicals. Of these, at least 250 are toxic to the body and about 70 have been shown to damage lung cells and increase the risk of developing cancer. At first, the body knows how to repair this damage, but over time it is very difficult to prevent cells from mutating.

Therefore, the main cause of lung cancer is smoking . However, it can also appear in people who have never smoked or lived with smokers, in which case the causes are not too clear. It is believed that in these cases, the origin of the cancer would be by a complex interaction between genetics and the environment.

However, it is known that there are some risk factors beyond smoking, which are: having a family history, prolonged exposure to asbestos (a mineral used in construction), exposure to radon gas and other carcinogens … In general, any Long-term inhalation of toxins can damage lung cells and increase the risk of developing cancer.


Symptoms do not usually appear in the earliest stages. And when they do, the symptoms can be confused with those of some less serious respiratory disorders , so it is important to seek medical attention at the slightest doubt; especially if you are in the risk population: smokers over 45 years old.

Be that as it may, the most common clinical signs of lung cancer are the following:

  • Chest pain
  • Persistent cough
  • Coughing up blood
  • Weakness and fatigue
  • Involuntary weight loss
  • Difficulty breathing
  • Wheezing when breathing
  • Loss of appetite
  • Headache
  • Bone pain
  • Hoarseness

Other symptoms can often appear, although they are not as common and tend to appear in the later stages of cancer: facial paralysis, joint pain, swelling of the face or extremities, voice changes, nail defects, drooping of the eyelids, swallowing problems …

But these are just the signs that alert you to the presence of the tumor. The reason why it is such a lethal cancer is due to the complications it can lead to , which do represent serious health problems.


As we have said, the lungs are very important organs but they are also highly sensitive. When a malignant tumor develops inside, its functionality is affected, something that has implications for the health of the entire organism.

Next we will see the main complications that can derive from lung cancer , which explain why it is so lethal.

1. Respiratory failure

Lung cancer causes shortness of breath as the main airways can become blocked depending on the nature of the tumor. Over time, this shortness of breath may lead to respiratory failure, a situation in which the lungs are unable to take in enough oxygen to meet the body’s needs. This condition is very serious and is often fatal for the affected person.

2. Bleeding from the airways

Damage to lung cells can cause bleeding in the airways, a condition known as hemoptysis, which results in a coughing up of blood. It is a serious condition that requires immediate treatment because if the bleeding is severe, it can endanger the life of the person.

3. Metastasis

Lung cancer often spreads to other organs, that is, metastasizes. It can travel to the bones, the brain or other organs and give rise to symptoms according to the place to which it has spread.

When lung cancer has metastasized, it can no longer be cured . Treatments are focused on alleviating symptoms and prolonging the life of the patient.

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4. Pleural effusion

Lung cancer can cause a pleural effusion , meaning fluid builds up in the layers of tissue that line the lungs and chest cavity. This causes sharp pain and shortness of breath.

To prevent this situation from leading to more serious disorders, it is necessary to drain the fluid, as it is a condition that requires immediate attention.


Lung cancer is perhaps the most easily preventable type of cancer since 9 out of 10 cases are due to smoking . Therefore, the most effective prevention is not to start smoking or, if you do, to stop.

If you don’t smoke, the risk of developing lung cancer is much lower. In addition, it is important to avoid second-hand exposure to tobacco, check radon gas levels in your home, avoid exposure to carcinogens at work, etc.

However, we have said that some cases appear in people who, at least apparently, have never been exposed to carcinogens. In this case, prevention is more difficult, although as with all cancers, the risk is greatly reduced if healthy lifestyle habits are followed, that is, eating a healthy diet and doing physical exercise .


Detection of lung cancer begins when the person experiences the above symptoms and seeks medical attention, or when a doctor, during a routine examination, suspects the presence of a tumor.

First, some imaging test is done, as an X-ray may reveal abnormal growth in the lungs . If the results are not entirely reliable, a computed tomography (CT) scan may be done, which can indicate the presence of smaller cell masses that an x-ray cannot detect.

In case there are still doubts or the doctor needs to confirm it, the sputum test is performed. A sputum sample is analyzed using histology techniques, as a microscope visualization can reveal the presence of cancer cells.

Later, if the presence of a tumor needs to be confirmed as well as rejected, a biopsy can be performed, that is, a sample of lung tissue is removed in the area where the tumor is believed to be. This sample is analyzed in the laboratory and it has just been confirmed that the person suffers from lung cancer or not.


In the event that the presence of cancer in the lungs has been confirmed, treatment should begin as soon as possible, since the earlier it is started, the greater the probability that it will be successful, also reducing the risk of complications for the person. previously seen.

If the cancer has been detected in its early stages – which is not very common – and is located in a very specific point in the lungs, surgery to remove the tumor may be sufficient.

If the cancer is too large and / or there is a risk that it has started to spread, the surgery is most likely not enough and the doctor will have to recommend chemotherapy, radiotherapy, immunotherapy, administration of drugs or a combination of several .

However, for the reasons that we have presented above, treatment is not always successful as it is difficult to prevent the most serious complications from arising . This makes it one of the types of cancer with the lowest survival rate even if treatments are administered. Therefore, the best weapon is prevention.


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