Lung cancer is among the most common cancers worldwide. In the United States and other industrialized countries, it’s the major cause of cancer mortality.

Emphysema is a term that describes structural changes in the lung associated with chronic obstruction pulmonary disease (COPD)‚ but it’s not cancer.

The two lung diseases share important risk factors primarily due to the exposure of cigarette smoke. COPD is a known significant risk factor forlung cancer, while lung cancer has been linked to changes in lung function characteristic of emphysema. Let’s review the relationship between both emphysema and lung cancer

Emphysema is a chronic lung disease that falls under the umbrella of COPD. There are two main types of COPD —chronic bronchitis and emphysema.

  • Chronic bronchitis occurs when your airways become irritated and inflamed, resulting in buildup of mucus and obstructions.
  • Emphysema is a condition where the tiny air sacs (alveoli) in your lungs, which expand and shrink with each breath, lose elasticity.
    • The alveoli lose their ability to contract after expansion, and air stays trapped inside. Over time, this can cause irreversible damage to the alveoli.
    • Alveoli is where oxygen is transferred to your blood. So when there are fewer alveoli working, less oxygen gets to your blood.

While both conditions are linked to smoking, the aging process also results in a decline of lung function similar to that of someone with emphysema. As we age, three things happen: Alveoli can lose their shape and become overly compliant; the diaphragm — the main respiratory muscle — becomes weaker, decreasing the ability to inhale and exhale; and nerves in airways become less sensitive to foreign particles. When particles build up in the lungs, they can damage the lung tissue. These changes can result in symptoms such as fatigue, tiredness, and shortness of breath.

Lung cancer in itself is not COPD. Lung cancer occurs when abnormal lung cells multiply and crowd out the cells that normally help tissues and organs to function.

In some cases, lung cancers can be secondary, or spread to the lung from another location. However, 90 percent of lung cancers are linked to cigarette smoking.

While smoking cigarettes can directly damage your lungs, breathing second-hand smoke can also damage the lungs. Other toxins can also do this, including inhaled chemicals and other environmental pollutants.

Once these cells are damaged — from conditions like COPD — they are more prone to become abnormal, or cancerous.

While emphysema and lung cancer are two different conditions, they do share some associations and share the main risk factor for both which is cigarette smoking. Both can lead to immune system malfunction, inflammation, and cell damage which play a role in the development of the two diseases.

While the physiology of emphysema itself does not cause lung cancer or vice versa, either condition may create an environment in which the other can thrive. For example, cell damage from emphysema can cause stress and genetic changes in the lung tissue. Likewise, cancer cells can damage alveoli and other lung tissues, resulting in COPD-like conditions.

In fact, one study suggests that emphysema is the strongest known marker for the development of lung cancer. This is not to say that emphysema is lung cancer, only that people with emphysema are at a higher risk of eventually developing lung cancer.

The symptoms of emphysema and lung cancer are similar in some ways, but not all.

The following symptoms, on the other hand, are more common in people with lung cancer — although they may also occur in severe emphysema or during COPD exacerbations:

A doctor may evaluate you for COPD and/or screen you for lung cancer if you’re at high risk of either condition due to smoking, workplace exposure, or other factors.

You may be referred to a specialist, like a pulmonologist or oncologist, to find the most effective treatments. Early diagnosis and treatment are crucial for both diseases.

When it’s an emergency

Anyone can become short of breath from time to time, and it may be difficult to decide when your breathing problems have become serious enough to see a doctor, or even to call 911.

Shortness of breath and other breathing problems are considered an emergency if you:

Lung cancer and emphysema are two very different conditions, but they have similar risk factors, causes and symptoms. Both can be caused by cigarette smoking or other damage to lung tissues.

If you have trouble breathing, or a chronic cough that’s getting worse, see a healthcare professional.