About Lung Cancer

What is lung cancer?

Lung cancer is a type of cancer that starts in the lungs. Cancer from the lungs may spread to other areas of the body.1 When the cancer spreads, it is known as advanced lung cancer or metastasised lung cancer.1

If you have received a lung cancer diagnosis, you are not alone – lung cancer is one of the most common types of cancer.2

In Singapore, 4 people are diagnosed with lung cancer every day.2 It is the second most common cancer in Singaporean males, and the third most common in females.2,3,4

Types of lung cancer

There are different types of lung cancer, but the two most common types are:3

Non-small cell lung cancer (NSCLC):

The most common type of lung cancer. There are three subtypes:3,4,5


Adenocarcinoma – the most common form of NSCLC, which usually begins in the outer parts of the lungs.3,5


Squamous cell carcinoma – a type of lung cancer that tends to cause early symptoms, and normally begins in the central part of the lungs, near a main airway (bronchus).3,5


Large-cell carcinoma – tends to grow and spread rapidly, often presents symptoms late and begins in the outer edges of the lungs.3,5

Small cell lung cancer (SCLC):

lthough less common that NSCLC, SCLC is more aggressive and tends
to spread faster than NSCLC.3


Signs and symptoms

Early Stages
Late Stages3

Early Stages

- A cough that does not go away or one that gets worse
- Coughing up blood or rust-coloured sputum (spit or phlegm)
- A chest pain that worsens with deep breathing, coughing or laughing
- Hoarseness
- Weight loss and loss of appetite
- Shortness of breath
- Tiredness or weakness
- Recurrent infections such as bronchitis and pneumonia

Late Stages

- Bone pain in areas like the back and hips
- Skin and the whites of the eyes that turn yellow, indicating that the cancer has reached the liver
- Headaches, numbness in the arms or legs, balance problems, dizziness and other changes to the brain


Risk factors and prevention

Who is most at risk of lung cancer?

People above the
age of 403

Men, who are 3
times more at risk of
developing lung
cancer than women2

Smokers and people
exposed to tobacco smoke are at 15-25 times higher risk than non-smokers4

While the main cause for NSCLC, the most common type of lung cancer, is attributable to smoking and exposure to second hand tobacco smoke, those who have never smoked or been regularly exposed to tobacco smoke are also at risk. In Singapore, 25% of people living with lung cancer have never smoked.6

Other risk factors include:3
  • Second hand smoke (passive smoke) is a major risk factor of lung cancer among non-smokers. Passive smoking can increase the risk of developing lung cancer by about 30%. No amount of exposure to second-hand smoke is safe
  • Age. Lung cancer is more common in people above the age of 40.
  • Exposure to cancer-causing chemicals increases the risk of lung cancer, e.g. asbestos, coal gas, chromates, nickel, arsenic, vinyl chloride,mustard gas and radon.
  • Air Pollution. Those who live in more polluted cities have a higher risk of lung cancer than those who live in less polluted cities. The World Health Organisation estimates that there are about 4 million excess deaths per year worldwide due to air pollution. One of the largest reasons is due to lung cancer.
  • Personal or family history: the risk of lung cancer may be higher if your parents, brothers or sisters, or children have had lung cancer. A lung cancer survivor, especially those who have smoked, may develop another form of lung cancer.
Can lung cancer be prevented?4
  • Stay away from tobacco. The best way to reduce your risk of lung cancer is not to smoke and to avoid breathing in other people’s smoke.
  • Avoid radon exposure. Radon is an important cause of lung cancer. You can reduce your exposure to radon by having your home tested and treated, if needed.
  • Avoid or limit exposure to cancer-causing agents. Avoiding exposure to known cancer-causing agents, in the workplace and elsewhere, may also be helpful.
  • Eat a healthy diet. A healthy diet with lots of fruits and vegetables may also help reduce your risk of lung cancer. Some evidence suggests that a diet high in fruits and vegetables may help protect both smokers and non-smokers against lung cancer. But any positive effect of fruits and vegetables on lung cancer risk would be much less than the increased risk from smoking.

Screening and diagnosis

Who needs to be screened for lung cancer?7

If lung cancer is found early, when it is small and before it has spread, it is more likely to be successfully treated.

If you are at high risk of lung cancer (current or former smoker), speak to your doctor about screening for lung cancer.

Usually symptoms of lung cancer do not appear until the disease is already at an advanced stage. Even when lung cancer does cause symptoms, many people may mistake them for other problems, such as an infection or long-term effects from smoking. This may delay the diagnosis.6

In recent years, a test known as a low-dose CAT scan or CT scan (LDCT) has been studied in people at a higher risk of getting lung cancer. LDCT scans can help find abnormal areas in the lungs that may be cancer.6

How is lung cancer diagnosed?8

To establish a diagnosis, your doctor may ask about your medical history and perform a physical examination. Further diagnostic procedures and blood tests, such as a chest x-ray and computed tomography (CT) scan, may be needed to confirm the presence of lung cancer. Once lung cancer has been diagnosed and based on the type of lung cancer, your doctor will conduct further tests to find out the stage of cancer, i.e. whether the cancer is in its early stages or has spread to other parts of the body (advanced). These include physical exams, imaging tests, laboratory tests (such as blood tests), and biopsies (taking a sample of abnormal tissue to test it further).

The type and stage of lung cancer will inform the treatment plan.

1 Mayoclinic. Lung Cancer. Retrieved April 2021 from https://www.mayoclinic.org/diseases-conditions/lung-cancer/symptoms-causes/syc-20374620
2 Singapore Cancer Registry 50th Anniversary Monograph (1968 - 2017)
3 Singapore Cancer Society Lung Cancer Factsheet Retrieved July 2020 from https://www.singaporecancersociety.org.sg/learn-about-cancer/types-of-cancer/lung-cancer.html
4 Singapore Cancer Society. Cancer Basics. Retrieved Oct 2020 from https://www.singaporecancersociety.org.sg/13-cancer-basics.html
5 American Cancer Society - What is lung cancer? Retrieved on Feb 2021 from https://www.cancer.org/cancer/lung-cancer/about/what-is.html#:~:text=Non%2Dsmall%20cell%20lung%20cancer%20(NSCLC)&text=Adenocarcinoma%3A%20Adenocarcinomas%20start%20in%20the,cancer%20seen%20in%20non%2Dsmokers.
6 Parkway Cancer Centre : Lung Cancer - 5 Things You Need To Know. Retrieved April 2020 from https://www.parkwaycancercentre.com/sg/news-events/news-articles/news-articles-details/lung-cancer-5-things-you-need-to-know#:~:text=In%20Singapore%2C%20about%20one%2Dquarter,prolonged%20exposure%20to%20certain%20chemicals.
7 American Cancer Society. Lung cancer causes, risk factor and prevention. Retrieved October 2020 from https://www.cancer.org/cancer/lung-cancer/detection-diagnosis-staging/detection.html
8 National Health Services UK. Lung Cancer Diagnosis. Retrieved October 2020 from https://www.nhs.uk/conditions/lung-cancer/diagnosis/