Why Lung Cancer Happens

As an oncologist, I have dedicated my career to understanding lung cancer and helping my patients navigate its complexities. Lung cancer is a formidable disease that can affect anyone, regardless of lifestyle or background. In this blog, I aim to shed light on why lung cancer happens, identify its causes and risk factors, and discuss preventive measures to help you reduce your risk.

Understanding Why Lung Cancer Happens

Lung cancer occurs when cells in the lungs begin to grow uncontrollably, forming a tumor that can interfere with the lungs’ ability to provide oxygen to the bloodstream. The reasons behind this uncontrolled cell growth can be varied, and understanding them is key to prevention.

Causes of Lung Cancer

1. Smoking

Smoking is the most well-known cause of lung cancer, responsible for about 85% of cases. Cigarette smoke contains over 7,000 chemicals, many of which are carcinogens. These chemicals damage the cells lining the lungs. Over time, this damage leads to abnormal cell behavior and cancer.

2. Secondhand Smoke

Exposure to secondhand smoke is another significant cause of lung cancer. Even if you don’t smoke, inhaling smoke from nearby smokers can increase your risk. This risk is particularly high in environments where smoking is common.

3. Radon Gas

Radon is a naturally occurring radioactive gas that can seep into homes through cracks in the foundation. Long-term exposure to radon can damage lung cells and lead to cancer. Testing homes for radon and mitigating high levels can reduce this risk.

4. Asbestos and Other Carcinogens

Occupational exposure to asbestos, a material used in construction and manufacturing, can cause lung cancer. Other industrial substances, such as arsenic, diesel exhaust, and certain chemicals, also contribute to lung cancer risk.

5. Genetics

Genetic factors can play a role in lung cancer development. Certain genetic mutations increase the likelihood of developing lung cancer, making family history an important factor to consider. Although less common than environmental causes, genetics can significantly influence risk.

Risk Factors for Lung Cancer

Understanding why lung cancer happens involves looking at various risk factors that can increase the likelihood of developing the disease. While some risk factors are well-known, others might be less obvious.

1. Age

Lung cancer is more common in older adults. Most people diagnosed with lung cancer are 65 or older, with the average age at diagnosis being around 70. As we age, our cells accumulate more damage, increasing the risk of cancer.

2. Personal or Family History

Having a personal or family history of lung cancer can increase your risk. If you have had lung cancer before, you are at a higher risk of developing it again. Similarly, if a close family member has had lung cancer, your risk is higher.

3. Exposure to Carcinogens

Long-term exposure to harmful substances, whether at work or in the environment, can increase lung cancer risk. This includes not only smoking and secondhand smoke but also exposure to radon, asbestos, and other chemicals.

4. Chronic Lung Diseases

Chronic lung diseases, such as chronic obstructive pulmonary disease (COPD) or pulmonary fibrosis, can increase the risk of lung cancer. These conditions cause inflammation and damage to lung tissue, creating an environment where cancer can develop.

5. Air Pollution

Living in areas with high levels of air pollution can increase the risk of lung cancer. Particulate matter and other pollutants can damage lung cells over time, contributing to the development of cancer.

Prevention of Lung Cancer

While some risk factors for lung cancer cannot be controlled, such as age or genetic predisposition, there are several proactive steps that can be taken to reduce the risk.

1. Avoid Smoking and Exposure to Secondhand Smoke

The most effective way to prevent lung cancer is to avoid smoking and exposure to secondhand smoke. For smokers, quitting smoking is crucial. Support groups, nicotine replacement therapies, and medications can help with quitting.

2. Test for Radon

Testing your home for radon and taking steps to mitigate high levels can significantly reduce your risk of lung cancer. Radon testing kits are widely available, and professional mitigation services can address high radon levels.

3. Protect Yourself from Carcinogens

If you work in an environment with exposure to asbestos, diesel exhaust, or other harmful substances, take steps to protect yourself. Use protective equipment, follow safety protocols, and ensure proper ventilation in your workplace.

4. Maintain a Healthy Lifestyle

Eating a balanced diet rich in fruits and vegetables, staying physically active, and maintaining a healthy weight can help reduce your risk of lung cancer. These habits support overall health and strengthen the immune system.

5. Regular Health Check-ups

Regular health check-ups and screenings can help detect lung cancer early when it is more treatable. If you are at high risk for lung cancer, such as having a history of smoking or exposure to carcinogens, talk to your doctor about appropriate screening options.

Why Lung Cancer Happens: A Closer Look

Lung cancer develops due to a combination of genetic and environmental factors. While smoking remains the primary cause, other factors like secondhand smoke, radon exposure, and occupational hazards also play significant roles. Understanding these causes and risk factors can help in taking preventive measures.

The Role of Inflammation

Chronic inflammation in the lungs can lead to cellular damage and increase the risk of lung cancer. Conditions like COPD and pulmonary fibrosis cause prolonged inflammation, creating an environment conducive to cancer development.

Air Quality and Pollution

Exposure to pollutants and poor air quality can lead to lung damage over time. Industrial emissions, vehicle exhaust, and other airborne particles contribute to lung cancer risk. Living in areas with high pollution levels necessitates additional preventive measures.


Understanding why lung cancer happens, identifying its causes and risk factors, and taking preventive measures are crucial steps in reducing the risk of this disease. While some risk factors cannot be changed, many proactive steps can be taken to protect lung health.

As an oncologist, my goal is to raise awareness about lung cancer and encourage proactive measures to prevent it. By avoiding smoking, testing for radon, protecting yourself from carcinogens, maintaining a healthy lifestyle, and getting regular health check-ups, you can significantly reduce your risk of developing lung cancer. Remember, awareness and prevention are your best tools in the fight against lung cancer.