Lung Cancer 101: Small Cell or Non-Small Cell

Lung cancer is one of the most commonly diagnosed cancers worldwide, and understanding it is an important step in recognising symptoms early. One of the key distinctions doctors make when diagnosing lung cancer is distinguishing between Small Cell or Non-Small Cell Lung Cancer, as these two disease types behave differently.

At the National Cancer Centre Singapore (NCCS), we see patients who are being evaluated for possible lung cancer. Careful diagnostic assessment helps our oncologists to determine the specific type of disease and recommend the most appropriate treatment.

Although both Small Cell and Non Small Cell Lung Cancer affects the lungs, they differ in how quickly they grow, spread, and how they are treated.

Key Takeaways

• Lung cancer is broadly classified into two main types: small cell lung cancer and non-small cell lung cancer. 
• Non-small cell lung cancer is more common and includes several subtypes such as adenocarcinoma and squamous cell carcinoma. 
• Small cell lung cancer, which is less common, typically grows and spreads more rapidly than non-small cell lung cancer. 
• Symptoms such as persistent cough, chest discomfort, and breathlessness may appear in both types of lung cancer. 
• Early medical evaluation for persistent respiratory symptoms can help support timely diagnosis and treatment .

Understanding How Lung Cancer Develops

Lung cancer occurs when there is an uncontrolled growth of abnormal cells in the lung. These abnormal cells can form tumours which can interfere with normal lung function. As the disease advances, cancer cells may eventually spread to other parts of the body. 

The lungs contain several different types of cells, and lung cancer is classified based on which cells become cancerous. These differences influence how the disease behaves and how it is treated.

Key Differences between Small Cell and Non-Small Cell Lung Cancer

Doctors classify lung cancer primarily into two categories. The table below highlights how Small Cell or Non-Small Cell Lung Cancer differ in several important ways.   

Understanding these differences helps multidisciplinary teams determine the most appropriate treatment plan.

What Is Small Cell Lung Cancer?

Small cell lung cancer (SCLC) is a less common but more aggressive form of lung cancer. It tends to grow quickly and may spread to other organs earlier in the course of disease.

Because of this rapid progression, symptoms may appear suddenly or worsen quickly.

Typical Symptoms Of Small Cell Lung

Symptoms often develop when tumours affect the airways or surrounding structures.

Common symptoms include:

• Persistent cough 
• Chest discomfort or chest pain 
• Shortness of breath 
• Fatigue 
• Unintentional weight loss 
• Frequent respiratory infections

In some cases, small cell lung cancer can cause paraneoplastic syndromes (a set of signs and symptoms that develop when an individual has cancer), which occur when the tumour produces hormones or substances that affect other parts of the body such as the nervous system, joints, blood and skin.

How It Is Usually Diagnosed

Small cell lung cancer is often detected through imaging scans such as CT scans or chest X-rays when patients present with respiratory symptoms.

A biopsy is required to confirm the diagnosis and identify the cancer type.

What Is Non-Small Cell Lung Cancer?

Non-small cell lung cancer (NSCLC) accounts for the majority of lung cancer cases. It includes several subtypes that develop from different types of lung cells.

These subtypes may grow at different rates and respond to different treatments.

Major Subtypes Of Non-Small Cell Lung Cancer

Adenocarcinoma

Adenocarcinoma is the most common type of lung cancer. It often develops in the outer parts of the lungs and can occur in both smokers and non-smokers.

Squamous Cell Carcinoma

This subtype typically begins in the central airways of the lungs and is strongly associated with smoking.

Large Cell Carcinoma

Large cell carcinoma is less common but can occur in various parts of the lung and may grow quickly.

Understanding the subtype helps doctors choose the most appropriate treatment strategy.

Early Symptoms Of Lung Cancer

Patients Often Notice Regardless of whether the disease is Small Cell or. Non-Small Cell Lung Cancer, recognising these symptoms may help encourage timely medical consultation:

• Persistent Cough: A cough that does not improve over time or worsens gradually may require medical evaluation. 
• Shortness Of Breath: Difficulty breathing may occur if tumours affect airflow within the lungs. 
• Chest Pain: Pain in the chest area may develop if the tumour affects nearby tissues. 
• Hoarseness: Changes to the voice may occur if the tumour affects the nerves that control the vocal cords. 
• Fatigue And Weight Loss: Unexplained fatigue and weight loss can occur as the body responds to cancer.

These symptoms may also be associated with many other lung or respiratory conditions. A full medical assessment is important to diagnose the exact type of disease condition.

When Lung Cancer Spreads: Additional Symptoms

In more advanced stages, lung cancer may spread beyond the lungs. When this happens, additional symptoms may appear depending on which organs are affected.

Examples include:

• Bone pain if cancer has spread to bones 
• Headaches or neurological symptoms, if the brain is affected 
• Swelling in the face or neck due to pressure on blood vessels 
• Persistent fatigue and weakness

Doctors use imaging scans to evaluate whether lung cancer has spread and to determine the stage of the disease.

How Lung Cancer Is Diagnosed

Diagnosing lung cancer involves several different medical evaluations.

Imaging Tests

Imaging scans help doctors detect abnormal growths in the lungs.

Common imaging tools include:

• Chest X-rays 
• CT scans 
• PET scans

These scans help to identify tumours and indicate whether the cancer has spread.

Biopsy

Biopsies are a definitive method of diagnosing lung cancer.

During this procedure, a small sample of lung tissue is removed and examined under a microscope so that pathologists can determine whether the cancer is small cell or non-small cell.

Molecular Testing

For non-small cell lung cancer, additional testing may identify genetic mutations within the tumour.

These findings can guide targeted therapy treatment options.

Treatment Approaches For Small Cell and Non-Small Cell Lung Cancer

Treatment plans vary depending on the type and stage of cancer but may include:

• Surgery to remove tumours when possible 
• Chemotherapy to destroy cancer cells 
• Radiation therapy to target the affected areas 
• Targeted therapy for specific genetic mutations
• Immunotherapy to help the immune system recognise and destroy cancer cells

Patients may receive a combination of the above treatments depending on their condition.

The latest medical advances have expanded treatment options for lung cancer and improved outcomes for many patients.

Recognising Small Cell and Non-Small Cell Lung Cancer

Understanding Small Cell and vs. Non-Small Cell Lung Cancer helps patients recognise when persistent respiratory symptoms may require medical attention.

At the National Cancer Centre Singapore (NCCS), our multidisciplinary teams provide comprehensive evaluation, diagnosis, and personalised treatment planning for patients with lung cancer. Through coordinated care and advanced medical expertise, we aim to support patients through every stage of their cancer journey.

If you have a persistent cough, unexplained breathlessness, or other ongoing respiratory symptoms, seek professional medical advice early to get timely assessment and appropriate treatment.

Frequently Asked Questions

1. Can lung cancer develop in people who have never smoked?
   Yes. Although smoking remains the strongest risk factor, lung cancer can also occur in individuals who have never smoked. Environmental exposures, genetic factors, and air pollution may contribute to the risk of developing lung cancer. 
   
   
2. How long can lung cancer develop before symptoms appear?
   In some cases, lung cancer can develop silently for months or years before any noticeable symptoms appear. I Sometimes, imaging scans during evaluations for unrelated conditions detect lung cancer. 
   
   
3. Are lung nodules always cancer?
   No. Lung nodules are relatively common and may be caused by infection, inflammation, or benign growths. Additional tests such as a biopsy are often needed to determine whether a nodule is cancerous. 
   
   
4. Does early-stage lung cancer always cause symptoms?
   No, early-stage lung cancer may produce few or no symptoms. In some cases, the presence of cancer is only discovered during routine imaging or screening. 
   
   
5. What should someone do if they notice persistent lung symptoms?
   If symptoms such as cough, breathlessness, or chest discomfort persist for several weeks, it is advisable to seek prompt medical attention for proper evaluation and care.