Lung Cancer

What is lung cancer?

The lungs are composed of various structures that can be affected by lung cancer:

• Trachea (Windpipe): The main airway that directs air into the lungs, branching into the bronchi.
• Bronchi: Two main tubes (left and right bronchus) that further divide into smaller bronchioles, carrying air deeper into the lungs.
• Bronchioles: Smaller branches of the bronchi that lead to the alveoli.
• Alveoli: Tiny air sacs where oxygen is absorbed into the blood, and carbon dioxide is expelled.
• Lung Lobes: The right lung has three lobes, while the left lung has two lobes. Lung cancer can develop in any lobe.

Lung cancer typically originates in the cells lining the bronchi, bronchioles, or alveoli, leading to uncontrolled cell division and tumour formation. The development of lung cancer is often gradual, occurring over months or years, and early stages may not present noticeable symptoms, leading to delayed diagnosis.

There are two primary types of lung cancer.

• Non-Small Cell Lung Cancer (NSCLC): Accounting for approximately 80% to 85% of lung cancer cases.
  
• Small Cell Lung Cancer (SCLC): Comprising about 10% to 15% of lung cancers, SCLC is known for its rapid growth and early spread to other organs. It is strongly associated with smoking and is typically more aggressive than NSCLC.

The major differences between these two types of lung cancer are the size and shape of the cancer cell, forms of treatment and the speed at which the cancer spreads.

Between 2018 and 2022, lung cancer was the third most common cancer among males and females in Singapore. It remains the leading cause of cancer-related deaths among males in Singapore.

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Signs & symptoms

Symptoms may not be present in early-stage lung cancer and may appear in more advanced stages. Symptoms may include:

• Persistent cough
• Shortness of breath
• Chest pain
• Coughing up blood
• Recurring chest infection
• Hoarseness
• New onset of wheezing
• Loss of weight
• Loss of appetite

A doctor should be consulted if the above symptoms occur.

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What are the risk factors related to lung cancer?

There are several risk factors related to lung cancer:

• Habitual smokers are at the greatest risk and the risk is related to the number of cigarettes smoked and years smoked.
• People who are exposed to second-hand smoke.
• Vaping exposes users to a combination of harmful chemical substances like fine particulate matter (PM), cancer causing agents such as carbonyls and volatile organic compounds.
• Other risk factors include exposure to asbestos, radon gas, air pollution and certain heavy metals.
  

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What can you do to prevent lung cancer?

• Smoking is the leading cause of lung cancer. Quitting smoking at any age reduces the risk. If you are a non-smoker, do not start at all.
• Avoid secondhand smoke by distancing yourself from areas where people smoke.
• Avoid cancer causing substances. Protect yourself from air pollution, radon gas, and occupational hazards (asbestos, diesel exhaust, etc.).
• Do not vape.
• Consume more fruits, vegetables, and whole grains, and exercise regularly.
  

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Screening for lung cancer

The best way to protect yourself from lung cancer is through regular screenings, especially if you are at high risk. Lung cancer often develops without symptoms in its early stages, making early detection crucial for improving treatment outcomes. A low-dose CT (LDCT) scan is the most effective screening method for detecting lung cancer at an early, more treatable stage.

Note

• Lung cancer screening is not recommended for average-risk individuals due to potential risks from radiation exposure.
• High-risk individuals (aged 50-80) who have a history of heavy smoking (20 pack-years or more) or who have quit within the last 15 years should undergo annual LDCT screening.
• After age 80, screening should be based on overall health and doctor's advice.

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How is lung cancer diagnosed?

To detect lung cancer, the following tests are commonly used:

• Chest X-ray: The first-line imaging test used to detect abnormal masses or nodules in the lungs. However, it may not detect small tumours or those hidden behind other structures.
  
• Computed Tomography (CT) Scan: A more detailed imaging test that provides cross-sectional images of the lungs, helping to detect small tumours and assess their location, size, and spread.
  
• Positron Emission Tomography (PET) Scan: A functional imaging test that uses a small amount of radioactive glucose to identify active cancer cells, which consume more glucose than normal cells.
  
• Sputum Cytology: A non-invasive test that examines mucus (sputum) coughed up from the lungs under a microscope to detect cancerous cells. This test is most useful for detecting centrally located lung cancers.
  
• Lung Biopsy: A sample of cells is usually taken to confirm the diagnosis. A biopsy sample may also be taken from lymph nodes or other parts of the body where the cancer has spread.

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What are the treatment options for lung cancer?

At NCIS, our patients are managed by a team of cancer specialists and health professionals from various disciplines. From pathologists and radiologists to medical oncologists and surgeons, we believe that a multidisciplinary approach will give our patients comprehensive and holistic care. A treatment plan will be developed to fit each patient's needs and may include one or a combination of the following treatments:

Surgery

Surgery is the mainstay of treatment for early-stage NSCLC that remains within the lung. Surgeons would remove the area of the lung where the tumour is located and the surrounding lymph nodes. Minimally invasive 'keyhole' surgery is commonly performed in suitable patients which results in less pain and faster recovery. Types of lung resection include segmentectomy which removes segment within a lobe, lobectomy which removes one lobe of the lung, and pneumonectomy which removes one entire side of the lung.

Chemotherapy

Cancer cells are killed using drugs called chemotherapy. Chemotherapy may be given via an intravenous drip once every week or every few weeks. It may be used first for more advanced cancer, or for selected patients before or after surgery or combined with radiation therapy.

Targeted Therapies

Targeted therapies usually involve taking tablets that act by blocking or interfering with cancer growth signalling which may kill or control cancer cells. Additional tests on the tumour or a blood sample may be needed to find out if targeted therapies may be effective.

Immunotherapy

Immunotherapy uses our immune system to fight cancer by helping the immune system recognise and attack cancer cells. Immunotherapy is usually given through the vein every few weeks either on its own or with surgery, chemotherapy or radiotherapy. Further tests on the tumour sample or a blood sample might be needed to find out if immunotherapy is likely to work.

Radiation Therapy

Radiation therapy uses high energy X-rays to kill cancer cells. The process involves lying on a couch and with the help of advanced radiation machines and techniques, X-rays are accurately delivered to the tumour. Radiation therapy may be given daily for several days to a few weeks as determined by the radiation specialist.

Treatment options (by stages)

[Stage 1] Early-Stage Lung Cancer

The cancer has grown deeper into the lung tissue but has not spread to lymph nodes or distant sites.

Surgery (Main Treatment for Suitable Patients)

• Lobectomy (removal of one lobe of the lung) is the standard procedure.
• Segmentectomy or wedge resection may be considered for smaller tumours.

Radiation therapy: Used for patients unable to undergo surgery.

Adjuvant treatments (For high-risk cases where cancer may recur)

• Chemotherapy: Given after surgery if there's a risk of recurrence.
• Targeted Therapy (For Tumours with Specific Genetic Mutations)

[Stage 2] Localised Lung Cancer with Lymph Node Involvement

The cancer has spread to nearby lymph nodes but not to distant organs.

Surgery (Preferred for operable tumours)

• Lobectomy or pneumonectomy (removal of an entire lung) may be required, depending on tumour size and location.

Chemotherapy (Typically given after surgery)

• Helps destroy any remaining cancer cells and reduce recurrence risk.

Radiation Therapy(If surgery is not possible or as post-surgical treatment)

• May be used to eliminate residual cancer cells.

[Stage 3] Locally Advanced Lung Cancer

The cancer has spread to more lymph nodes in the chest or invaded nearby structures but has not spread to distant organs.

Combination treatment approach

• Chemotherapy & Radiation Therapy (Often Given Together)
• Surgery (For Select Patients with Limited Spread)
• Targeted Therapy or Immunotherapy (For Tumours with Specific Genetic Mutations)

[Stage 4] Metastatic or Advanced Lung Cancer 

The cancer has spread to distant organs such as the brain, liver, or bones.

• Chemotherapy: primary treatment to slow disease progression
• Targeted Therapy: for specific gene mutations such as EGFR, ALK, or ROS1
• Immunotherapy: helps the immune system attack cancer cells
• Radiation Therapy: used for symptom relief and to target metastatic sites
• Palliative Care: improve quality of life and manage symptoms such as pain and breathing difficulty

Surgical Options

Surgery is a primary treatment option for early-stage non-small cell lung cancer (NSCLC) when the tumour is confined to the lungs. The type of surgery depends on the tumour's size, location, and whether it has spread to nearby lymph nodes. The following surgical options may be recommended:

Lobectomy – The most common lung cancer surgery where an entire lobe of the lung (one of the sections of the lung) containing the tumour is removed. This is often the preferred option if the cancer is localised within one lobe.

Segmentectomy (Segmental Resection) – A lung-sparing procedure that removes a segment of a lung lobe instead of the entire lobe. It is performed for small tumours or for patients who cannot tolerate a lobectomy due to reduced lung function.

Wedge Resection – Removal of a small, wedge-shaped portion of the lung containing the tumour along with a margin of healthy tissue. This is typically done for very early-stage lung cancer or for patients with limited lung function.

Pneumonectomy – The removal of an entire lung when the tumour is large or centrally located. This is usually considered when other lung-sparing surgeries are not possible.

Sleeve Resection (Sleeve Lobectomy) – A specialised surgery where part of the bronchus (main airway) is removed along with a lung lobe. The remaining lung tissue is then reattached to preserve lung function. This is an alternative to pneumonectomy for certain centrally located tumours.

Minimally Invasive Surgical Approaches

• Video-Assisted Thoracoscopic Surgery (VATS) – A minimally invasive technique where small incisions and a tiny camera (thoracoscope) are used to guide the removal of the tumour. This results in faster recovery and less pain.
  
  
• Robotic-Assisted Thoracic Surgery (RATS) – A robotic surgical system is used to perform precise lung cancer surgery with enhanced visualisation and dexterity.
  

Lymph Node Dissection

In all lung cancer surgeries, nearby lymph nodes are usually removed and examined to determine if cancer has spread.

Post-Surgery Treatment

Depending on the cancer stage, additional treatments such as chemotherapy, radiation therapy, targeted therapy, or immunotherapy may be required to reduce the risk of recurrence.

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Post treatment

Recovering from lung cancer treatment involves managing side effects, improving lung function, and maintaining overall well-being.

Regular Medical Follow-Up

• Scheduled Check-Ups: Attend follow-up visits for imaging tests (e.g. CT scans) to monitor for recurrence.
• Monitor Symptoms: Report any new symptoms like persistent cough, breathlessness, or chest pain to your doctor.

Lung Health and Breathing Support

• Pulmonary Rehabilitation: Engage in breathing exercises to strengthen lung function.
• Avoid Respiratory Irritants: Stay away from smoke, air pollution, and chemicals that may affect lung health.
• Oxygen Therapy: Some patients may require supplemental oxygen to improve breathing.

Physical Activity and Strength Building

• Gradual Exercise: Walking, light stretching, and strength training help regain stamina.
• Energy Conservation: Take breaks between activities and avoid overexertion.

Nutrition and Hydration

• High-Protein Diet: Supports tissue repair and energy levels.
• Hydration: Helps with lung mucus clearance and overall health.

Mental and Emotional Well-Being

• Counselling and Support Groups: Connect with others who have experienced lung cancer.
• Relaxation Techniques: Mindfulness, meditation, and deep breathing can help reduce anxiety.

Lifestyle Adjustments

• Quit Smoking: If applicable, quitting smoking improves lung function and reduces recurrence risk.
• Avoid Infections: Get vaccinated for flu and pneumonia, and practice good hygiene.

By following these post-treatment guidelines, lung cancer survivors can improve their quality of life and maintain overall health.