Lung cancer is a type of cancer that begins when abnormal cells grow uncontrollably in lung tissue. These abnormal cells may become cancer cells, form a tumour, damage nearby healthy cells and, as cancer spreads, reach lymph nodes or other parts of the body.
The risk of developing lung cancer varies among individuals. Lung cancer can affect people who smoke, people who previously smoked and people who have never smoked. The type of cancer, its stage and the person’s general health help determine the appropriate treatment.
Lung Cancer in Singapore
Lung cancer is a significant health concern in Singapore. According to the Singapore Cancer Registry Annual Report 2023, it was the third most common cancer in Singapore from 2019 to 2023. It was also a major cause of cancer death.
Many lung cancer cases are found after the cancer has reached a later stage. However, imaging performed for screening or another medical reason may identify some lung cancer cases in the early stages, before symptoms develop.
Lung Cancer Symptoms
Early-stage lung cancer may not cause noticeable symptoms. Common symptoms of lung cancer can include:
- A new cough that does not improve
- A change in a long-standing cough
- Coughing up blood
- Breathlessness
- Chest pain
- Hoarseness
- Repeated lung infections
- Unexplained weight loss
- Loss of appetite
- Ongoing tiredness
These common symptoms do not always mean cancer. Lung infections and other lung conditions can cause similar changes. A persistent or unexplained symptom should still be assessed by a doctor.
Seek urgent medical care for coughing up more than a small amount of blood, severe breathlessness or sudden chest pain. Learn more about lung cancer symptoms, causes and risk factors.
Causes and Risk Factors
Lung cancer starts when abnormal cells in lung tissue develop changes in their DNA. These changes allow cancer cells to grow when they should not and survive longer than healthy cells. Over time, the cancer cells may form a tumour and damage healthy cells.
Tobacco smoking, especially cigarette smoking, is a major risk factor. Smoking tobacco exposes lung tissue to cancer-causing substances. The risk of lung cancer increases with the amount and number of years smoked. Cigarette smoking causes most lung cancers, although lung cancer also occurs in people who have never smoked.
Other lung cancer risk factors include:
- Exposure to secondhand smoke
- Increasing age, which is linked to an increased risk
- Exposure to asbestos, radon or workplace carcinogens
- Air pollution
- Previous radiotherapy to the chest
- A personal or family history of lung cancer
- Certain long-term lung conditions
Having one or more risk factors does not mean a person will develop lung cancer. Some people develop lung cancer without known risk factors or a family history.
Types of Lung Cancer
The two main types of lung cancer are non-small cell lung cancer and small cell lung cancer.
These types of lung cancer differ in behaviour and treatment.
- Non-small cell lung cancer (NSCLC) is the more common group. Its main subtypes include adenocarcinoma, squamous cell carcinoma and large cell carcinoma.
- Small cell lung cancer (SCLC) is less common. It generally grows and spreads more quickly than NSCLC.
A pathologist examines cancer cells under a microscope to distinguish the types of lung cancer. Molecular testing may identify biomarkers in cancer cells that can influence treatment selection.
How Lung Cancer Is Diagnosed
Lung cancer diagnosis usually starts with a medical history, physical examination and imaging. A chest X-ray may show an abnormal area but cannot diagnose lung cancer. A CT scan provides more detailed information about the area’s size and location.
Further assessment may include:
- PET-CT to look for active cancer in the chest cavity or other parts of the body
- Magnetic resonance imaging, also called MRI, particularly when imaging of the brain is needed
- Bronchoscopy to examine the airways and collect tissue
- Needle biopsy guided by CT or ultrasound
- Endobronchial ultrasound to sample nearby lymph nodes
- Lung function tests before possible surgery
A biopsy removes cancer cells or tissue for laboratory examination. Samples from the tumour or lymph nodes can diagnose lung cancer, show whether it has spread, identify its type and guide molecular testing. Read about lung cancer diagnosis and treatment.
Lung Cancer Stages at a Glance
Cancer staging describes the tumour’s size and whether it has spread to nearby lymph nodes or other parts of the body. NSCLC usually uses stages 1 to 4.
Stage | General extent |
Stage 1 | Cancer is confined to the lung and has not reached the lymph nodes. |
Stage 2 | Cancer may be larger, involve nearby structures or reach nearby lymph nodes. |
Stage 3 | Cancer has spread more extensively within the chest, including certain lymph nodes or nearby structures. |
Stage 4 | Cancer has spread to another part of the body or meets other criteria for metastatic disease. |
The early stages are generally more localised. Advanced disease may extend further through the chest cavity or to other parts of the body.
Small cell lung cancer may also be described as limited-stage or extensive-stage disease. The complete guide to lung cancer stages explains these classifications in more detail.
Lung Cancer Treatment
Lung cancer treatment options depend on:
- The cancer type and stage
- The tumour’s biomarkers
- Whether the cancer can be removed surgically
- Lung function and general health
- Previous treatments
- The person’s goals and preferences
Treatment options may involve surgery, radiation therapy (radiotherapy), chemotherapy, targeted therapy or immunotherapy. Some people receive more than one of these treatment options. Radiation therapy and chemotherapy can kill cancer cells. Therapy may be given before surgery to shrink the cancer or afterwards to reduce the risk of recurrence.
Targeted therapy acts on specific molecular changes within cancer cells. Immunotherapy helps the immune system recognise or attack cancer. These treatments are not suitable for every tumour, so pathology and biomarker results are important. Clinical trials may offer other treatment options for eligible patients.
Supportive and palliative care may be used at any stage, including advanced disease, to manage pain, breathlessness, tiredness and other effects of cancer or its treatment. Support groups may provide practical and emotional help. See the overview of lung cancer treatment in Singapore.
When Surgery May Be Considered
Surgery is most often considered for early-stage lung cancer when it is localised NSCLC that can be removed and the person has sufficient heart and lung function for an operation. It may also form part of treatment for selected cases of locally advanced cancer.
Operations range from removing a small part of the affected lung to removing a lobe or, less commonly, an entire lung. The operation may use conventional open surgery or a minimally invasive approach, such as Video-Assisted Thoracoscopic Surgery (VATS), depending on the tumour and the person’s condition.
Read more about suitability, surgical approaches, risks and recovery on the lung cancer surgery page.
Lung Cancer Screening in Singapore
Lung cancer screening looks for early-stage lung cancer before symptoms develop. It differs from diagnostic testing, which investigates a symptom or an abnormal imaging result.
Singapore’s 2025 guidelines state that annual low-dose CT screening may be offered to people who:
- Are 50 to 80 years old
- Have smoked at least 20 pack-years
- Currently smoke or stopped within the past 15 years
- Are medically able and willing to undergo further evaluation and treatment if needed
Screening should not currently be offered to non-smokers. It can also produce false-positive results and identify lung nodules that require follow-up but are not cancer.
People with symptoms need diagnostic assessment rather than screening. Learn about eligibility, benefits and limitations of lung cancer screening in Singapore.
Prognosis
Whether lung cancer is curable depends on the stage at diagnosis, cancer type, tumour biomarkers, general health and response to treatment.
For some people with early stage disease, treatment can aim to cure the cancer. Advanced disease may not be curable, but treatment can sometimes control it, relieve symptoms and help people live longer. Population survival figures cannot predict what will happen to an individual person.
Reducing Lung Cancer Risk
No method can prevent lung cancer completely. Not smoking and quitting smoking reduce the risk of developing lung cancer. Quitting smoking remains beneficial even after many years of smoking.
Other measures include avoiding secondhand smoke, following workplace safety requirements, and reducing exposure to known cancer-causing substances where possible. These steps cannot prevent lung cancer in every case.
Thoracic Surgical Care at Neumark
Neumark Lung & Chest Surgery Centre specialises in minimally invasive thoracic surgery with a multidisciplinary approach led by Dr Harish Mithiran, senior consultant thoracic surgeon at Gleneagles and Mount Alvernia hospitals.
A thoracic surgical assessment may be appropriate when imaging shows a suspicious lung lesion, a biopsy confirms potentially operable cancer, or the treating team recommends reviewing surgical options.
References
Reviewed by Medical Experts
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Our health articles are evidence-informed and medically reviewed by medical professionals to support clear, accurate and current thoracic information. The information provided is not intended as medical advice. More about our medical experts.
