About Lung Cancer

About Lung Cancer

Lung cancer begins in the tissues of the lungs—usually in the cells lining the air passages. It is one of the most common and serious cancers worldwide. While smoking remains the biggest risk factor, lung cancer can also affect people who have never smoked. Understanding the symptoms, stages, and treatment options can help with early detection and better outcomes.

What Is Lung Cancer?

Lung cancer occurs when abnormal cells in the lungs grow uncontrollably. These cells can form tumours and may spread (metastasise) to other parts of the body, such as the brain, bones, liver, or adrenal glands.

There are two main types

Non-Small Cell Lung Cancer (NSCLC) – This is the most common type, accounting for about 80–85% of cases. It includes subtypes like adenocarcinoma, squamous cell carcinoma, and large cell carcinoma.

Small Cell Lung Cancer (SCLC) – A faster-growing and more aggressive form, often strongly linked to heavy smoking.

Causes and Risk Factors

Smoking is responsible for most lung cancer cases. The risk increases with the number of cigarettes smoked per day and the number of years a person has smoked. However, non-smokers can also develop lung cancer due to:

Exposure to secondhand smoke

Air pollution

Radon gas exposure

Occupational exposure to asbestos, arsenic, or diesel exhaust

Family history of lung cancer

In countries like India, indoor air pollution from biomass fuels (used for cooking) also increases risk.

Symptoms of Lung Cancer

Early-stage lung cancer often does not cause noticeable symptoms. That’s why many cases are diagnosed at an advanced stage. When symptoms do appear, they may include:

Persistent cough that does not go away

Coughing up blood (hemoptysis)

Shortness of breath

Chest pain that worsens with deep breathing or coughing

Hoarseness

Unexplained weight loss

Fatigue

Frequent lung infections such as pneumonia or bronchitis

If the cancer spreads, symptoms may include headaches (if it spreads to the brain), bone pain, or swelling in the face and neck.

Because these symptoms can resemble common respiratory conditions, people often ignore them. Any persistent or unusual respiratory symptom lasting more than 2–3 weeks should be evaluated by a doctor.

Stages of Lung Cancer

Staging describes how far the cancer has spread and helps guide treatment decisions.

For Non-Small Cell Lung Cancer (NSCLC), stages range from 0 to IV:

Stage 0 (Carcinoma in situ): Cancer cells are limited to the airway lining.

Stage I: Cancer is confined to the lung and has not spread to lymph nodes.

Stage II: Cancer has spread to nearby lymph nodes within the lung.

Stage III: Cancer has spread to lymph nodes in the chest or nearby structures.

Stage IV: Cancer has spread to distant organs such as the brain or liver.

For Small Cell Lung Cancer (SCLC), staging is usually divided into

Limited Stage: Cancer is confined to one side of the chest.

Extensive Stage: Cancer has spread beyond one lung or to other parts of the body.

Early-stage cancer has a better prognosis and more treatment options.

Diagnosis

Doctors use several methods to diagnose lung cancer:

Chest X-ray

CT (Computed Tomography) scan

PET scan

Sputum cytology (examining mucus for cancer cells)

Biopsy (removing a small tissue sample for testing)

In high-risk individuals, low-dose CT screening can detect lung cancer at earlier stages, improving survival rates.

Treatment Options

Treatment depends on the type, stage, genetic characteristics of the tumour, and the patient's overall health.

1. Surgery

Surgery is often recommended for early-stage NSCLC. The surgeon may remove a small section of the lung (lobectomy) or, in some cases, the entire lung (pneumonectomy).

2. Chemotherapy

Chemotherapy uses drugs to kill cancer cells. It may be used before surgery (neoadjuvant therapy), after surgery (adjuvant therapy), or as the main treatment in advanced cases.

3. Radiation Therapy

Radiation uses high-energy rays to destroy cancer cells. It may be used alone or combined with chemotherapy.

4. Targeted Therapy

Some lung cancers have specific genetic mutations (such as EGFR or ALK mutations). Targeted drugs are designed to block these specific changes, often with fewer side effects than chemotherapy.

5. Immunotherapy

Immunotherapy helps the body’s immune system recognise and attack cancer cells. Drugs known as immune checkpoint inhibitors have improved survival in advanced lung cancer.

6. Palliative Care

For advanced stages, palliative treatment focuses on relieving symptoms and improving quality of life.

Prevention and Early Detection

The most effective way to reduce lung cancer risk is to avoid tobacco in all forms. Quitting smoking at any age significantly lowers the risk. Other preventive measures include:

Avoiding secondhand smoke

Testing homes for radon

Using protective equipment in high-risk workplaces

Reducing exposure to air pollution

For high-risk individuals (usually long-term smokers over age 50), annual low-dose CT scans may help detect cancer early.

Final Thoughts

Lung cancer is a serious but increasingly treatable disease, especially when detected early. Advances in targeted therapy and immunotherapy have improved survival rates in recent years. Awareness of symptoms, timely screening, and lifestyle changes—particularly avoiding smoking—play a crucial role in reducing risk and improving outcomes.