Understanding Lung Cancer

Lung cancer refers to cancers that begin in the lungs, the organs responsible for taking in oxygen and removing carbon dioxide from the body. It is one of the more commonly diagnosed cancers worldwide and can affect people of different ages and backgrounds. In Singapore, lung cancer continues to be a major health concern. According to the Singapore Cancer Registry Annual Report 2023, lung cancer is the third most common cancer in Singapore and one of the top leading causes of cancer death.

At NCCS, lung cancer care incorporates comprehensive assessment, specialised imaging and pathological testing, supported by multidisciplinary decision-making. This page summarises lung cancer diagnosis, staging, treatment strategies and supportive care services.

What Is Lung Cancer

Lung cancer occurs when genetic alterations in lung cells lead to unchecked growth and division. As these cells accumulate, they may form a tumour that disrupts normal lung activity.

Cancer may begin in the airways, air sacs or other lung tissues. As the disease progresses, it may spread to nearby lymph nodes or to other parts of the body, such as the brain, bones or liver. Early detection and timely treatment play an important role in improving outcomes.

Types of Lung Cancer

Lung cancer is broadly classified based on how the cancer cells appear under a microscope. The two main types are non-small cell lung cancer and small cell lung cancer.

Non-Small Cell Lung Cancer (NSCLC)

Non-small cell lung cancer is the most common type of lung cancer. It tends to grow more slowly than small cell lung cancer and includes several subtypes, such as adenocarcinoma and squamous cell carcinoma.

Small Cell Lung Cancer (SCLC)

Small cell lung cancer is less common but grows and spreads more quickly. It often requires prompt treatment and is commonly managed with systemic therapies.

Symptoms of Lung Cancer

Lung cancer may not cause noticeable symptoms in its early stages. As the cancer grows, symptoms may develop and can include:

• A persistent or worsening cough 
• Coughing up blood 
• Shortness of breath 
• Chest pain or discomfort 
• Hoarseness 
• Unexplained weight loss or loss of appetite 
• Fatigue 
• Recurrent chest infections

These symptoms can be caused by many non-cancerous conditions. Any persistent or unusual symptoms should be assessed by a doctor to determine whether further evaluation is needed.

Causes and Risk Factors for Lung Cancer

Lung cancer develops because of genetic changes in lung cells, often influenced by environmental and lifestyle factors.

Non-modifiable Risk Factors

• Increasing age 
• Family history of lung cancer 
• Previous radiation exposure to the chest

Modifiable or Environmental Factors

• Smoking, including long-term or past smoking 
• Exposure to second-hand smoke 
• Occupational exposure to substances such as asbestos 
• Air pollution

Not everyone with lung cancer has a history of smoking. Lung cancer can also occur in people who have never smoked.

How Lung Cancer Is Diagnosed

Diagnosing lung cancer involves a combination of imaging tests, laboratory investigations and tissue sampling to confirm the presence of cancer and identify its characteristics.

Imaging Tests

Common imaging tests include:

• Chest X-ray 
• CT scans to assess tumour size and location 
• PET scans to evaluate spread to lymph nodes or distant organs 
• MRI scans in selected cases

Tissue Sampling and Biopsy

A biopsy is usually required to confirm lung cancer. Tissue samples may be obtained through:

• Bronchoscopy 
• Needle biopsy guided by imaging 
• Surgical procedures in selected cases

The sample is examined to determine cancer type and guide treatment planning.

Molecular and Genetic Testing

In non-small cell lung cancer, molecular testing is often performed to identify specific genetic changes. These results help determine whether targeted therapies or immunotherapy may be suitable.

Staging and Classification

Lung cancer staging describes how far the cancer has developed within the lungs and whether it has spread beyond the chest. Staging in lung cancer reflects how advanced the disease is, including involvement beyond the lungs. It is a key factor in selecting treatment strategies and defining treatment goals.

Assessing Tumour Involvement in the Lungs

Doctors assess the size of the tumour and its exact location within the lung. This includes evaluating whether the cancer affects:

• The main airways or smaller breathing passages 
• Nearby lung tissue 
• Structures within the chest, such as the chest wall or major blood vessels

The position of the tumour can influence symptoms, treatment options and whether surgery is possible.

Lymph Node Involvement

Lung cancer commonly spreads to lymph nodes within the chest before reaching other parts of the body. Doctors carefully assess:

• Lymph nodes close to the lungs 
• Nodes between the lungs (mediastinal lymph nodes) 
• Nodes above the collarbone in more advanced cases

The extent of lymph node involvement helps determine cancer stage and guides decisions about surgery, radiation therapy and systemic treatment.

Spread Beyond the Chest

In more advanced lung cancer, cancer cells may spread to distant organs. Common sites include:

• The brain 
• Bones 
• Liver 
• Adrenal glands

Imaging tests are used to detect whether spread has occurred, as this affects treatment planning and overall management.

Why Staging Matters

Knowing the stage of lung cancer allows doctors to select treatments that are most appropriate, while also taking overall wellbeing of the patient into account. Patients are encouraged to speak to their doctor about how staging relates to their condition.

Treatment for Lung Cancer

At NCCS, lung cancer treatment is tailored to each individual following detailed assessment by a multidisciplinary team. Factors such as cancer subtype, stage, tumour location and lung function are carefully considered, and treatment often involves a combination of therapies.

Surgery

Surgery may be recommended for selected patients with early-stage non-small cell lung cancer when the cancer is confined to the lung and lymph node involvement is limited or absent. The aim is to remove the tumour completely while preserving as much healthy lung tissue as possible.

Surgical procedures may involve removal of:

• A small section of the lung (segmentectomy or wedge resection) 
• An entire lobe of the lung (lobectomy)
• In selected cases, a larger portion of the lung

Suitability for surgery depends on tumour location and whether the lungs can function well after the operation.

Radiation therapy

Radiation therapy delivers carefully planned radiation to target cancer cells in the chest area. It is a key component of lung cancer management and may be recommended:

• As the main form of treatment when surgery is not appropriate 
• Together with chemotherapy for certain locally advanced cancers 
• Following surgery to lower the chance of recurrence 
• For symptom control in advanced disease, including relief of pain, breathlessness or persistent cough

Modern radiation therapy methods are designed to focus treatment on the tumour while limiting exposure to healthy lung tissue and surrounding organs.

Chemotherapy

Chemotherapy involves the use of medicines that travel through the bloodstream to target cancer cells. In lung cancer care, it may be given:

• Prior to surgery or radiation therapy to reduce tumour size 
• Following surgery to lower the likelihood of the cancer returning 
• As primary treatment when the disease has spread beyond the lungs

Depending on the cancer’s characteristics and stage, chemotherapy is often used alongside radiation therapy, immunotherapy or targeted therapies to improve treatment effectiveness.

Targeted Therapy

Certain lung cancers are driven by specific genetic alterations that promote tumour growth. Targeted therapies work by interfering with these pathways and are prescribed only when molecular testing shows that the cancer is likely to benefit.

These treatments are often given as oral medications and may be used in selected cases of advanced lung cancer where actionable genetic changes have been identified.

Immunotherapy

Immunotherapy works by enhancing the body’s natural immune response against cancer. In lung cancer care, it may be introduced:

• As a standalone treatment or combined with chemotherapy for selected advanced cases 
• Following combined chemotherapy and radiation therapy, to help maintain disease control

The use of immunotherapy is guided by tumour features and results from immune marker testing, which help determine whether this approach is appropriate.

Why Treatment Planning Is Important

As lung cancer can behave differently from one person to another, treatment plans are tailored with care. Understanding the expected outcomes and possible side effects helps patients make choices that reflect their health priorities.

Supportive Care and Living With Lung Cancer

Alongside cancer treatment, supportive care is an essential part of lung cancer management. By addressing symptoms such as breathlessness and reduced energy, it helps patients cope with daily challenges and maintain overall wellbeing.

Support may include:

• Management of breathlessness and cough, including breathing techniques, medication and oxygen support when needed 
• Pain and symptom control, particularly for chest discomfort, fatigue or treatment-related side effects 
• Pulmonary rehabilitation, which may involve supervised exercises and strategies to improve breathing efficiency and stamina 
• Nutritional guidance, especially for patients experiencing weight loss, reduced appetite or swallowing difficulties 
• Emotional and psychological support, helping patients and families cope with anxiety, uncertainty and lifestyle changes 
• Social and practical assistance, including support with daily activities, work-related concerns and care planning

Follow-Up and Monitoring

Follow-up focuses on monitoring lung function, identifying treatment-related effects and detecting any signs of recurrence or disease progression as early as possible.

Follow-up care may include:

• Chest imaging, such as CT scans or X-rays, to monitor the lungs and surrounding structures 
• Assessment of breathing and lung function, especially in patients who have undergone surgery or radiation therapy 
• Blood tests, to evaluate overall health and monitor for treatment-related effects 
• Physical examinations, with attention to respiratory symptoms such as cough, breathlessness or chest discomfort

The schedule and type of follow-up care may vary depending on lung cancer stage, treatment history and recovery. Prompt reporting of any new or worsening respiratory symptoms helps ensure timely care intervention.

Guidance and Support at NCCS

Receiving a lung cancer diagnosis often brings both medical and practical concerns. At NCCS, care is delivered through close collaboration among specialists to ensure that treatment decisions, management of symptoms and supportive care are well coordinated. Attention is given not only to cancer treatment, but also to function and quality of life.

Patients are supported with clear explanations and access to appropriate informational resources, and are encouraged to raise concerns at any point. Involving patients in care discussions helps to ensure that treatment plans reflect individual needs and priorities.

For further information about lung cancer or to discuss your individual care plan, please speak with your NCCS care team or visit www.nccs.com.sg.

Commonly Asked Questions

1. Can lung cancer be detected early if I feel well?

In some individuals, lung cancer is detected during imaging done for other reasons or through surveillance in higher-risk groups. Early-stage lung cancer may not cause any symptoms.

2. Is lung cancer only caused by smoking?

No. While smoking is a major risk factor, lung cancer can also occur in people who have never smoked due to environmental, occupational or genetic factors.

3. Will treatment affect my breathing permanently?

Some treatments may temporarily affect breathing, while others have minimal long-term impact. Your care team will monitor your lung function and provide support to manage symptoms.

4. How do doctors decide between chemotherapy, targeted therapy or immunotherapy?

Treatment choice depends on cancer type, stage and molecular test results. Your care team will explain which options are suitable for your care.

5. Can lung cancer be managed as a long-term condition?

Yes. Advances in treatment mean that some people live for extended periods with controlled disease. Ongoing monitoring and supportive care are important.