Lung cancer usually starts as a cough or shortness of breath. Chest pains follow; more signs and symptoms come. Each year, lung cancer kills 1.3 million people, making it the most common cause of cancer-related death. There are two main categories: non-small-cell and small-cell carcinoma and several types of lung cancer, each having its own characteristics.

From early warning signs to stage IV bronchioloalveolar carcinoma, the following article features the causes, symptoms, types, and stages of lung cancer.

Causes and risk factors

The easiest way to get lung cancer is to smoke tobacco. Even secondhand smoke increases your risk. Along with a family history, other risks to increase chances of developing lung cancer include:
  • High levels of air pollution;
  • Arsenic in drinking water;
  • Radon gas;
  • Asbestos;
  • Exposure to cancer-causing chemicals like uranium, coal products, gasoline and diesel exhaust.


With smokers, a cough is usually dismissed as simply a cough. If it does not go away or blood comes with it, it is usually a sign of something serious. Wheezing, shortness of breath and chest pains are other commonly ignored symptoms of lung cancer.
Other signs include loss of appetite, weight loss, weakness, fatigue, difficulty in swallowing, hoarse voice, joint pain, facial paralysis, drooping eyelids, or bone pain. Some of the signs are associated with less serious conditions, so it is important to see your doctor if you are experiencing some of them.

Non-small-cell lung carcinoma

Non-small-cell lung carcinoma, the most common form of lung cancer, is broken up into three categories:


This type usually starts near the central bronchus, where a hollow cavity and necrosis (death of cells) form in the center of the tumor.


This is the most common form of lung cancer in nonsmokers. It affects peripheral lung tissue. A subtype, bronchioloalveolar carcinoma, is the type most commonly found in women who never smoke.

Large-cell lung carcinoma

This type grows and spreads quickly in any part of the lung, making treatment difficult.

Small-cell lung carcinoma

Small-cell lung carcinoma forms in the larger airways and is strongly linked with smoking. While less common, it carries a worse prognosis because it has usually metastasized (spread to other organs) by the time it is detected. Metastasis is explained below.


Metastatic cancer begins in one part of the body and spreads to other areas. Part of the reason why lung cancer is so deadly and hard to treat is that metastasis starts early on after cancer has formed. Common sites for lung cancer metastasis include the adrenal glands, liver, brain, and bone. The lungs are a common place where other metastatic cancers can land.

Stages of cancer

Lung cancer uses the TNM classification scale, which denotes several characteristics. Larger numbers mean the tumor is more advanced.
The more common staging scale uses Roman numerals:
  • Stage 0: Cancer is only present in the cells where it formed.
  • Stage I: Cancer has grown but has not metastasized.
  • Stage II, III: While still local to its origin, the cancer is spreading and possibly affecting other organs nearby.
  • Stage IV: Cancer has fully metastasized and spread to other organs throughout the body.

Stay informed

Lung cancer can be deadly but you can help prevent it. The easiest way to cut down your risk is to quit smoking and instantly start feeling the benefits. Within minutes, your body will start to recover.
Along with a good diet, exercise, and other healthy choices, staying informed about the risks of lung and other cancers is the key to prevention.
Hello Health Group does not provide medical advice, diagnosis or treatment.
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