Lung Cancer

Lung cancer

What is Lung Cancer?

Cancer is the leading cause of death in Singapore1. It can occur anywhere in the body, but lung cancer is cancer that develops in the lungs. The lungs are two sponge-like organs consisting of the left and right lung. The right lung is made up of three lobes, while the left lung is smaller and made up of two lobes. When air is breathed in, it goes into the lungs which consist of the bronchi, bronchioles, and alveoli. The exchange of gases (oxygen and carbon dioxide) occurs here between the alveoli and the blood, for the removal of carbon dioxide and the supply of fresh oxygen.

Lung cancers usually begin with abnormal cell growth in the bronchi, bronchioles, or alveoli. There are two main types of lung cancer2,3:

  • Non-small cell lung cancer (NSCLC): most common type of lung cancer and accounts for approximately 85% of all lung cancers. Develops from the epithelial cells (cells that line the organs) and includes adenosarcomas, large cell carcinoma, and squamous cell carcinoma.
  • Small cell lung cancer (SCLC): accounts for 15% of lung cancer, associated with smoking, and spreads quickly and easily to other parts of the body.

What causes Lung Cancer?

Cancer cells are cells that grow/multiply out of control due to a genetic defect or mutation, when this happens, they grow to form either a non-cancerous (benign) tumour or a cancerous (malignant) tumour. There are a number of ways in which cells can be mutated, these are:

  • Inherited: sometimes genetic defects are inherited and passed down through generations.
  • Smoking: cigarette smoke can cause our normal cells to mutate into cancer cells.
  • Alcohol: excessive consumption of alcohol can mutate our normal cells into cancer cells.

What are the symptoms?

Like all cancer, there are many stages of lung cancer. Early-stage lung cancer rarely causes any symptoms, however, if they do appear, they may look like this4:

  • Recurrent or worsening cough
  • Chest pain that worsens when you breathe or cough
  • Bloody or phlegmy cough
  • Wheezing
  • Lethargy or fatigue
  • Loss of appetite
  • Unintentional weight loss
  • Hoarseness
  • Recurrent respiratory infections

Late-stage lung symptoms include4,5:

  • Jaundice
  • Numbness in arms and legs
  • Dizziness
  • Oedema or swelling in the face
  • Breathlessness or shortness of breath
  • Bone pain
  • Headache
  • Muscle weakness
  • Droopy eyelids
  • Lumps in the neck or collarbone

Is Lung Cancer painful?

Yes, lung cancer can be painful for some individuals. Some painful symptoms include chest pain, bone pain, and headaches.

Who is at risk of Lung Cancer in Singapore?

There are various factors that may increase your risk of lung cancer, these are6:

  • Smoking: smoking significantly increases your risk of lung cancer. The risk of lung cancer increases with every cigarette you smoke and for every year you have smoked7.
  • Second-hand smoke: exposure to second-hand smoke also increases your risk of lung cancer.
  • Radiation therapy: any radiation therapy aimed at your chest for another type of cancer (e.g., breast cancer) can increase your risk of lung cancer.
  • Family history: if you have relatives with lung cancer, your risk increases.
  • Exposure to certain elements: exposure to asbestos, radon gas, and other carcinogens increases your risk of lung cancer.

Some of these factors can be avoided such as smoking, and exposure to certain elements, however, other factors like family history cannot be avoided.

How is Lung Cancer diagnosed in Singapore?

Lung cancer can be diagnosed using the following tests2:

  • X-ray: an x-ray of your lungs will be taken to identify any tumours or growths on your lungs which could be a sign of lung cancer.
  • Computed tomography scans (CT-scans): more accurate version of x-rays which can identify small tumours or growths that may be missed by an x-ray.
  • Sputum tests: mucus from deep within your lungs can reveal the presence of lung cancer.
  • Lung biopsy: samples of your lung will be taken and biopsied for signs of lung cancer.

These are just diagnostic tests to check for the presence of lung cancer, there are other additional tests to check the extent or stage of your lung cancer.

These tests include2:

  • Bone scan: checks to see if the lung cancer has spread to your bones.
  • Positron emission tomography (PET) scan: a radioactive glucose solution is injected into the body. Areas of the body with cancer will show a higher and quicker uptake of the glucose solution. 
  • Magnetic resonance imaging (MRI): detailed images to check if lung cancer has spread to other areas of the body.
  • Mediastinal staging: for individuals with suspected stage 3 lung cancer.
  • Endobronchial Ultrasound: a bronchoscope with an ultrasound probe attached is used to check for the presence of tumours or growths.
  • Mediastinoscopy: samples are taken from the lymph nodes in the chest to check if the cancer has spread beyond the lungs.
  • Video-assisted thoracoscopy surgery (VATS): another way to attain samples from the lymph nodes in the chest.

What are the treatment options for Lung Cancer in Singapore?

The treatment options for lung cancer vary depending on the stage of your lung cancer. Treatment options include:

  • Surgery
  • Radiofrequency ablation (RFA)
  • Radiation therapy
  • Chemotherapy
  • Targeted drug therapy
  • Immunotherapy
  • Palliative procedures

Frequently asked questions

Can lung cancer be cured?

Early screening of all cancers will increase your chances of survival. Early detection of lung cancer can result in a cure rate of 80 to 90%. However, if lung cancer is detected in the late stage, the 5-year survival rate is only 18.6%.  

Does lung cancer spread rapidly?

Yes, lung cancer is aggressive and spreads quickly.


  1. National Cancer Centre Singapore. (2022, September 26). Cancer Screening. Retrieved from National Cancer Centre Singapore: 
  2. SingHealth. (n.d.). Lung Cancer. Retrieved from SingHealth: 
  3. Ann Pietrangelo, S. B. (2022, April 12). Lung Cancer: Everything You Need to Know. Retrieved from healthline: 
  4. Cleveland Clinic Medical Professional. (2019, July 10). Lung Cancer. Retrieved from Cleveland Clinic:
  5. Lauren G Collins, C. H. (2007). Lung cancer: diagnosis and management. American Family Physician, 56-63.
  6. Mayo Clinic Staff. (2022, March 22). Lung cancer. Retrieved from Mayo Clinic:
  7. Brett C Bade, C. S. (2020). Lung Cancer 2020: Epidemiology, Etiology, and Prevention. Clinic in Chest Medicine, 1-24.
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