- Causes of Lung Cancer:
Smokers, be it active or passive, accounts for more than 80 per cent of lung cancer patients. Exposure to chemicals like asbestos and arsenic also leads to lung cancer, one of the most dangerous cancers.

- Risk Factor:
Like most cancers, lung cancer affects the older people. People above 70 years of age are more at risk of getting lung cancer. Smoking is the main risk factor. The longer you smoke the greater your risk. However, not all smokers have lung cancer so hereditary factor too could play a role here.

- Types of Lung Cancer:

There are four types of lung cancer

• Small cell lung cancer:
  Of every 100 patients diagnosed with lung cancer, 20 suffer from this type of cancer. Smoking is the main cause of this type of cancer. In this type, small cancerous cells are present in lungs. It spreads very quickly and quite early therefore chemotherapy is recommended by the doctors.
• Squamous cell carcinoma:
  Cancerous cells are found in the middle of the lung. Smoking is one of the main causes of this type of cancer that is very common.
• Large cell carcinoma:
  Cancerous cells are large and round in shape and they spread very quickly.
• Adenocarcinoma:
  Cancerous cells are found in phlegm-producing cells in the periphery of lungs.

Small cell lung cancer, squamous cell carcinoma and large cell carcinoma is caused by smoking while adenocarcinoma is caused by low-tar cigarettes.

- Symptoms:
In lung cancer, patient could feel difficulty in breathing and chest pain. They may also lose weight and their appetite and feel tired very quickly. They may also spit blood while coughing. However, sometimes no symptoms are seen until the cancer is in an advanced stage.

- Diagnosis:
X-rays can detect lung cancer. But the reliable method is bronchoscopy, where a thin tube is placed in the lungs and doctors extract a sample of the tissue for examination under microscope to detect cancer. To know the extent of growth of cancer, CT scan, or bone scan can be done.

- Treatment:
Since small lung cancer spread quite quickly surgery cannot be of much use. Therefore doctors recommend chemotherapy or radiation therapy or both in combination.

Surgery is done to take away tumor if it is in a limited area. In some cases where cancerous cells have spread, radiation therapy is used in place of surgery. Chemotherapy too can be used in combination i.e. if done before surgery it will help reduce the tumor or if done after surgery it would destroy the cancerous cells left behind.

Lung cancer cannot be fully cured. The most the treatment can do is to extend patient’s life by some years. Of every five patients suffering from lung cancer, four die within a year of their diagnosis.

- Side Effects:
One may feel tired very quickly and lose hair especially in chemotherapy. Nausea and vomiting are some of the side effects.