Lung cancer is a type of cancer that begins in the lungs, and that is called primary lung cancer. Cancer that begins in another part of the body and spreads to the lungs is secondary lung cancer.

There are two main types of primary lung cancer, classified by the type of cells in which the cancer starts. They are:

  • non-small-cell lung cancer, which is the most common type, occurring in 80% of the cases; can be either squamous cell carcinoma (caused by smoking, develops in the cells that line the airways), adenocarcinoma (cells that produce mucus in the airway lining; this type becomes more common) or large-cell carcinoma (known also as undifferentiated carcinoma; the name is given from the large cell)
  • small-cell lung cancer is less common type, it usually spreads faster than non-small-cell lung cancer; it is called small because the cancer cells look very small under a microscope; it is usually caused by smoking

Other types of lung cancer are:

  • Mesothelioma, which affects the covering of the lungs (the pleura); it is cancer of the membrane that covers the surface of the lungs and the inside of the chest; it usually occurs in people exposed to asbestos.
  • Carcinoid tumour, very rare type

Lung cancer is rare in people younger than 40. It mainly affects older people. 



Symptoms of lung cancer are:

  • Frequent cough
  • Shortness of breath
  • Coughing up phlegm (sputum), sometimes with blood
  • Pain during breathing or coughing
  • Loss of appetite
  • Tiredness
  • Weight loss

In more advanced stage of lung cancer, the symptoms include:

  • hoarse voice
  • difficulty swallowing
  • changes in the shape of your fingers and nails
  • Swelling of the face
  • Swelling in the neck
  • Chest and shoulder pain
  • Pain under the ribs on the right side (if there are cancer cells in the liver)
  • Pleural effusion (fluid around the lungs)



The cause of lung cancer is smoking in most of the cases. However, as non-smokers develop lung cancer, it cannot be stated as the only cause.


Risk Factors

The risk factors of lung cancer are:

  • smoking
  • exposure to chemicals, asbestos, radon gas
  • family history



Complications from lung cancer are:

  • pleural effusion
  • hemoptysis (coughing blood)
  • metastasis in the brain and the bones



Prevention of lung cancer may be possible if the following measures are taken: leading a healthy lifestyle in terms of eating healthy food, more fruits and vegetables, quit smoking, regular exercises, and avoidance of carcinogenic substances.