Causes of Lung Cancer

Lung cancer is not only associated with smoking. Let's see what other factors influence its development.
Causes of Lung Cancer

Last update: 06 August, 2021

According to the World Health Organization (WHO), 2.2 million cases of lung cancer were diagnosed worldwide in 2020. That same year there were 1.8 million deaths, emerging as the most dangerous cancer in terms of numbers of deaths. Despite these statistics and the awareness about it, a good part of the population ignores the causes of lung cancer.

Most associate this type of cancer with smoking. Although it’s true that a large percentage of cases correspond to tobacco, there are other causes and risk factors that are reported in thousands of annual diagnoses. Today we’ll explore all the ways that lung cancer can occur.

Main causes of lung cancer

Lung cancer occurs when lung cells mutate or change. This process is usually caused by the interaction with toxic substances, although it can also develop for no apparent reason. According to the American Lung Association, the main causes of lung cancer are as follows:


Causes of lung cancer include smoking
The dangers of exposure to cigarette smoke in the development of lung cancer are so great that most prevention programs try to eliminate this addiction.

Smoking is the most common cause of lung cancer. According to some researchers, 90% of cases can be attributed to this habit. The risk of developing the disease is greater in men than in women and, despite attempts in this regard, there’s no consensus on the average number of packs smoked per year that could cause the carcinogenic manifestation.

Although the risks are greater for active smokers, secondhand smoke also increases the chances of developing the disease (as the evidence suggests). The risk remains latent among ex-smokers, even decades after they have given up smoking. However, in these cases, the percentage is lower. Therein lies the importance of quitting tobacco.

Exposure to radon

Exposure to radon, a naturally occurring radioactive gas, is the second most common cause of lung cancer. Studies indicate that it causes 21,000 deaths each year from this disease. Paradoxically, researchers have found that up to 50% of the population are unaware of its incidence or have misconceptions about it.

Radon is a natural gas that we can find in rocky soils. It’s produced by the decomposition of uranium, and, for that reason, it’s prevalent in almost every part of the world.

In most places, its levels of concentration aren’t harmful to health, but, in certain areas, the exposure is higher. There are radon tests sold in hardware stores so you can check the levels in your area.

Exposure to certain chemicals

As we pointed out at the beginning, chemical exposure is one of the main causes of lung cancer. There are dozens of chemicals associated with this type of cancer. We highlight the most important:

  • Asbestos: Asbestos is a group of minerals that was used for decades in the construction industry. Today there’s a consensus among researchers that it represents a risk for developing lung cancer.
  • Uranium: There’s also evidence that suggests that exposure to uranium increases the risk of this type of cancer. Those who live or have lived in mining areas may be more likely to develop it.
  • Cadmium: In 1993 cadmium was described as carcinogenic to humans by the IARC (International Agency for Research on Cancer). Studies also indicate that it can cause prostate cancer.
  • Chromium: Exposure to chromium has been associated with this lung disease. Evidence suggests that it can also cause chronic inflammation and other problems.

Other chemicals such as arsenic, nickel, petroleum products, and soot, just to mention a few, have also been associated with the condition.

Particle contamination

This category includes all solid or liquid particles that are found in the air we breathe. According to its toxicity, the risk of lung cancer increases.

Researchers have agreed for decades that smoke from motor vehicles, industrial waste, power plants and other generators are linked to the disease.

The higher the degree of contamination of the geographic area where you live, the greater the exposure of your lungs to certain toxins.


Finally, the last of the most common causes of lung cancer is genetic predisposition. If you have a history of lung cancer or other cancers in your family network, even if the above criteria aren’t met, it’s likely that you’ll develop the disease in the future as well.

However, many of the cases have no family history. Researchers have tried to find the genes responsible. So far the 5p15, 6p21, and 15q25 loci are suspected to be among the first culprits.

There’s still a long way to go in this regard, although the genetic role explains many of the processes that generate the disease.

Risk factors for lung cancer

In the company of the previous causes, we can also mention some risk factors that influence the course of the disease. Among the main ones, we can highlight the following.

Intake of vitamin supplements

As Johns Hopkins Medicine points out, vitamin supplements can work against you in the development of the disease. Specifically, beta-carotene supplements have been associated with this variety of cancer. The risks are greater if the person maintaining the intake is a recurrent smoker or drinker. The incidence decreases in people without these habits.

Exposure to radiation therapy

This is a risk factor highlighted by the Centers for Disease Control and Prevention (CDC). If you’re a cancer survivor and during treatment you were exposed to radiation therapy, then you have a higher risk of manifesting the condition in contrast to a healthy person.


Causes of lung cancer include old age
Age is a very important risk factor for the development of this and other types of malignant tumors.

As with most types of cancer, your risk increases as you age. Studies indicate that most cases are diagnosed in patients over 60 years of age.

Although it’s rare for it to occur in people under 45, the odds are still latent. As we’ve already mentioned, it’s more common in men than in women.

When to consult the doctor?

Both causes and risk factors should alert you as to when is the right time to seek medical assistance. If you’re a smoker, even an occasional smoker, you should know the risks you’re exposing yourself to in the medium and long term. From everyone here at MuySalud, we’d like to encourage you to kick the habit, especially if you have started recently.

If you want to keep smoking, we recommend that you schedule annual visits with the specialist to rule out any lung damage that could lead to cancer.

If you’ve been exposed for years to any of the above-mentioned chemical agents, are over 60 years old, or have a family predisposition, you should also seek assistance to rule out this condition.

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