Stealing the last breath: Lung Cancer

Lung cancer causes abnormal growths in the lungs that can interfere with breathing.

What Is Lung Cancer?

Lung cancer develops when cells in the lungs begin to grow out of control. Normally, healthy cells grow, divide, and die in an orderly way. Cancer cells keep growing and dividing, forming a mass called a tumour. In lung cancer, these abnormal cells usually start in the airway lining.

Lung cancer can be classified into two major types:

• Primary lung cancer – cancer that starts in the lungs

• Secondary lung cancer – cancer that begins elsewhere and spreads (metastasizes) to the lungs

Cancer cells damage normal lung tissue and interfere with the lungs’ ability to transfer oxygen into the bloodstream. Over time, this can cause shortness of breath and other serious symptoms.

Lung cancer most often affects people over the age of 40, and the likelihood increases with age.

How Common Is Lung Cancer in Singapore?

In Singapore, lung cancer is one of the top cancers by incidence and mortality:

• It consistently ranks among the top three most commonly diagnosed cancers in Singapore.

Lung cancer is among the leading causes of cancer death, particularly in men.

• A significant proportion of lung cancer diagnoses occur in people who have never smoked.

These statistics highlight the serious impact lung cancer has on public health locally.

Causes and Risk Factors

1. Smoking (The Major Cause)

Smoking tobacco is the single largest risk factor for lung cancer. Smokers are estimated to have 15 to 25 times the risk of developing lung cancer compared to non-smokers. The more cigarettes smoked and the longer the smoking history, the greater the risk.

Tobacco smoke contains numerous carcinogens (cancer-causing chemicals) that damage lung tissue over time and lead to mutations in the DNA of lung cells.

2. Second-hand Smoke

People who do not smoke but are regularly exposed to smoke from others still face increased risk — even at home or work. Second-hand smoke contains many of the same harmful chemicals as direct smoking and contributes to lung cancer risk.

3. Environmental & Occupational Exposures

Certain workplace exposures have been linked to lung cancer, including:

• Asbestos

• Chromium and nickel

• Coal tar and gas

• Radon gas

Radon is a naturally occurring gas that can accumulate in buildings. Prolonged exposure to high levels increases lung cancer risk.

4. Air Pollution

Air pollution — long-term exposure to fine particulate matter (PM2.5) — is associated with a modestly increased risk of lung cancer. Outdoor and indoor air pollution contributes to chronic irritation and inflammation of lung tissues.

5. Genetic and Other Factors

Even without smoke or chemical exposure, lung cancer can occur. Around a quarter of lung cancer cases in Singapore occur in people who have never smoked. Genetics, family history, and other unknown factors may play a role.

Common Symptoms of Lung Cancer

Lung cancer often develops slowly. Early symptoms may be subtle or mistaken for other conditions. Possible symptoms include:

• Persistent cough that doesn’t go away

• Pain in the chest, shoulder, or back

• Changes in the colour or thickness of sputum

• Breathing difficulty (shortness of breath)

• Trouble swallowing

• Hoarseness of voice

• Wheezing or noisy breathing

• Recurring bronchitis or pneumonia

• Coughing up blood (even in small amounts)

Symptoms vary depending on the tumour’s location and size. Because early signs can be subtle, many patients are diagnosed at a later stage.

Imaging tests such as chest X-rays and CT scans help detect lung tumours and assess disease progression.

How Lung Cancer Is Diagnosed

If lung cancer is suspected, your doctor may recommend:

• Chest X-ray – first imaging to check for abnormalities

• CT scan – detailed imaging to define tumour size and location

• Sputum cytology – microscopic exam of coughed-up mucus

• Bronchoscopy and biopsy – direct tissue sampling

• PET scan – to check for spread of cancer

Biopsy confirmation remains the gold standard for diagnosis.

Treatment Options

Treatment varies by cancer type, stage, and overall health. Options include:

Surgery

Surgical removal of the tumour may be an option in early stages.

Radiation Therapy

High-energy beams target and destroy cancer cells.

Chemotherapy

Drugs that kill cancer cells or slow growth.

Targeted Therapy

Medications that act on specific genetic mutations of the cancer.

Immunotherapy

Boosts the immune system to recognise and attack cancer cells.

Combination therapy is common. The treatment plan is personalised by a multidisciplinary oncology team.

Can Lung Cancer Be Prevented?

While not all cases can be prevented, risk reduction is possible:

Quit Smoking

Stopping smoking remains the most effective way to reduce lung cancer risk at any age.

Avoid Second-hand Smoke

Choose smoke-free environments and advocate for clean air at home and work.

Limit Exposure to Workplace Risks

Use protective equipment and follow safety regulations if you work with hazardous substances.

Test for Radon

Home radon testing and mitigation can lower risk.

Healthy Lifestyle

Balanced diet, regular exercise, and routine health check-ups support overall lung health.

When to See a Doctor

Seek medical advice if you experience:

• A cough lasting more than 3–4 weeks

• Persistent chest discomfort

• Unexplained weight loss or fatigue

• Blood in sputum

Early evaluation improves chances for timely diagnosis and treatment. PRIME

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