• Cigarette smoking – It can be the main cause of lung cancer. Cigarette smokers are 10 to 30 times more likely to develop lung cancer than nonsmokers. Nicotine in cigarettes destroys lung cells, causing abnormalities of the cells. The likelihood of developing cancer depends on the number of the cigarettes usually smoked and number of the years a person has been smoking.
• Toxic substances and environmental pollution – Cigarette smoke, asbestos, radon, arsenic, radiation and other chemicals, including dust and vapors from nickel, chromium and other metals, can be risk factors for lung cancer.
• Age – The older a person is, the higher the risk of lung cancer. In general the risk increases after the age of 40, but even those younger may develop lung cancer.
• Family history – Those with the history of lung cancer in parents and siblings are at a higher risk for lung cancer when compared with those without this family history, even if they are nonsmokers.

Normally, people with early lung cancer do not show any of the symptoms. However, when the disease spreads, the following symptoms may be experienced. 

• Chronic cough (dry or productive cough)
• Breathing problems, such as the shortness of breath
• Wheezing
• Chest pain
• Hemoptysis
• Hoarseness
• Frequent lung infections, such as pneumonia
• Weakness or fatigue
• Unexplained weight loss

• Biopsy
  • Fine-needle aspiration – The doctor inserts a small needle through the chest and directly into the lung tumor to remove a small sample of tissue for testing. Often a chest CT scan or special x-ray machine called a fluoroscope is used to guide the needle.
  • Bronchoscopy – The doctor passes a thin, flexible tube with a light on the end into the mouth or nose, down through the main windpipe, and into the breathing passages of the lungs. Tiny tools inside the tube will take samples of fluid or tissue, which will then be examined by the pathologist.   
  • Thoracentesis – A needle is inserted through the chest wall and into the space between the lung and the wall of the chest where fluid is collected for analysis for cancer cells.
  • Mediastinoscopy – The surgeon examines and takes a sample of the lymph nodes in the center of the chest (underneath the breastbone) by making a small incision at the top of the breastbone.
  • Thoracoscopy – The doctor will insert a camera inside a thin tube to look inside the chest to see where the cancer is and incise a tissue sample from the lung for examination.
• Imaging tests of lung cancer
  • CT scan and MRI – These tests enable the doctor to determine the location and size of the abnormal cells in the lung.
  • Positron emission tomography (PET) scan – A mixture of sugar and radioactive substance will be injected intravenously. The lung cancer cells absorb this sugar mixture faster and in larger amount than normal cells. They will appear brighter. This enables the differentiation between normal cells and cancer cells.

• Stages of small cell lung cancer
  • Limited stage – Cancer cells are located only in the lung area.
  • Extensive stage – Cancer cells have spread to other parts of the body. 
• Stages of non-small cell lung cancer
  • Stage 1: Cancer cells are found only in the lung. They are not found in lymph nodes and have not spread to other organs.
  • Stage 2:
    • Stage 2A: The cancer cells are small and are found in nearby lymph nodes.
    • Stage 2B: The cancer cells are slightly larger and have spread to the lymph nodes near the affected lung or cancer cells have spread to another area such as the chest wall.
  • Stage 3:
    • Stage 3A: Cancer cells have spread to the lymph nodes far away from the affected lung or the cancer cells are found in the lymph nodes near the affected lung and have spread to other areas such as chest wall or the middle of the chest.
    • Stage 3B: Cancer cells have spread to the lymph nodes at the other side of the chest or to the lymph node above the collarbone or there is more than one tumor in the lung orthe cancer has grown into another area in the chest, such as the heart or esophagus or there is fluid containing cancer cells surrounding the lung.
  • Stage 4: Cancer cells have spread to other parts of the body such as the liver, bone, and brain.  

1. Surgery

• The objective of the surgery is to remove cancer cells and lymph nodes of your chest.
• Not used for treatment of small-cell lung cancer that can rapidly spread to other organs.
• Used to treat non-small cell lung cancer stage 1, 2, and 3A.

2. Radiotherapy

• Uses high energy x-rays to kill cancer cells.
• Cannot be used to treat metastatic lung cancer.
• Takes a short period of time and causes no pain. However, possible side effects include difficulty swallowing, fatigue, loss of appetite, and skin irritation at the treatment site.

3. Chemotherapy – Use of drugs to kill cancer and delay the growth of cancer cells. Most chemotherapy used for lung cancer is injected into a vein.
4. Targeted therapy

• Targets only at cancer cells and does not affect the normal cells.
• Effective treatment and there are no side effects like chemotherapy.

5. Combination therapy – To be most effective cancer treatment is done using a combination of therapies, as deemed appropriate by your oncologist.

• Stop smoking if you are a regular smoker.
• When you have recovered physically, exercise regularly by walking at least 15-30 minutes a day to improve lung and heart function.
• See your doctor as scheduled to prevent relapse and the spread of cancer to other parts of the body (metastatic cancer).