Lung Cancer: Symptoms, Causes and Treatment

By Medical Expert Team

Dec 21 , 2023 | 7 min read

What is Lung Cancer? 

Lung cancer, also known as lung carcinoma, is a malignant tumour that originates in the lungs and has the potential to spread throughout the body. To gain a comprehensive understanding of this disease, it's essential to explore its different facets, including its causes, types, risk factors, and associated symptoms and treatment options.

What are the Causes of Lung Cancer? 

Some of the most common causes for lung cancer include:

Tobacco Smoking: This is the leading cause of lung cancer. The risk of lung cancer increases with the number of cigarettes smoked and the number of years a person has smoked. Even secondhand smoke (exposure to smoke in the environment) can increase the risk of lung cancer.

Exposure to Radon Gas: Radon is a naturally occurring radioactive gas that can accumulate in homes and buildings. It's the second leading cause of lung cancer.

Exposure to Asbestos: People who have been exposed to asbestos, especially those who work in industries like shipbuilding, asbestos mining, and insulation, have a higher risk of developing a type of lung cancer called mesothelioma.

Exposure to Certain Chemicals and Substances: These include arsenic, chromium, nickel, beryllium, cadmium, tar, and soot. Workers in certain industries may be more exposed to these substances.

Air Pollution: Prolonged exposure to polluted air can increase the risk of lung cancer.

Types of Lung Cancer

Broadly, there are two primary types of lung cancer: Small Cell Lung Cancer and Non-Small Cell Lung Cancer.

Small Cell Lung Cancer (SCLC): This type of lung cancer is known for its rapid growth and propensity to spread quickly to other parts of the body. It is often associated with heavy tobacco smoking, and approximately 9 out of 10 cases of SCLC occur in men, while 8 out of 10 cases occur in women who smoke.

Non-Small Cell Lung Cancer (NSCLC): NSCLC comprises several subtypes, including adenocarcinoma, squamous cell carcinoma, and large cell carcinoma. Unlike SCLC, NSCLC tends to grow more slowly and is typically diagnosed at a more advanced stage.

Metastatic Lung Cancer: This cancer begins in one lung and then spreads to the other lung or other organs. Treating metastatic lung cancer is more challenging compared to cancer that remains confined to its initial site.

Other Types of Lung-Related Cancers: Apart from lung cancer, there are various other types of cancers that can originate in or around the lungs. These include lymphomas (cancer affecting the lymph nodes), sarcomas (cancer that develops in bones or soft tissues), and pleural mesothelioma (cancer that forms in the lining of the lungs). It's important to note that these conditions are distinct from lung cancer and are treated differently.

What are the Symptoms of Lung Cancer? 

The early signs of lung cancer often include a persistent cough and shortness of breath. However, symptoms can vary, and some individuals may not show any early signs.

Early Symptoms of Lung Cancer

  • A persistent or worsening cough
  • Coughing up phlegm or blood
  • Chest pain that intensifies during deep breaths, laughter, or coughing
  • Hoarseness
  • Wheezing
  • Weakness and fatigue
  • Loss of appetite, leading to weight loss
  • Frequent respiratory infections, such as pneumonia or bronchitis

Late-stage Symptoms of Lung Cancer

The specific symptoms experienced in late-stage lung cancer are contingent upon the location of new tumour growth. It's important to note that not everyone with advanced lung cancer will encounter all these symptoms:

  • Neck or collarbone lumps
  • Bone pain, particularly in the back, ribs, or hips
  • Headaches
  • Dizziness
  • Balance issues
  • Numbness in the arms or legs
  • Jaundice, characterised by yellowing of the skin and eyes
  • Drooping of one eyelid and constricted pupils
  • Reduced perspiration on one side of the face
  • Shoulder pain
  • Swelling of the face and upper body

Additionally, lung cancer tumours can, on occasion, release substances akin to hormones, resulting in a diverse range of symptoms known as “paraneoplastic syndrome”. These symptoms include:

  • Muscle weakness
  • Nausea and vomiting
  • High blood pressure
  • Elevated blood sugar levels
  • Confusion
  • Seizures

Checkout - Gastrointestinal Cancer Treatment

Risk Factors for Lung Cancer 

Various risk factors can increase an individual's risk of developing lung cancer. These include:

  • Family History: Having a family member with lung cancer increases your risk.
  • Radiation Therapy: Previous chest radiation therapy raises the risk.
  • Lung Diseases: Conditions like COPD or pulmonary fibrosis can heighten susceptibility.
  • Age: Risk increases with age, especially in older individuals.
  • Diet and Lifestyle: Some diets and lifestyles may contribute to increased risk.
  • Infections: Certain infections, like tuberculosis, are linked to higher risk.
  • Genetic Factors: Some individuals may have genetic traits that increase susceptibility.

Lung Cancer Diagnosis

Diagnosing lung cancer is a multifaceted process that encompasses clinical evaluation, imaging studies, and laboratory tests. In this comprehensive guide, we will take you through the step-by-step journey of diagnosing lung cancer.

Clinical Evaluation

During the clinical evaluation for lung cancer, the following key steps are undertaken:

  • History Taking: The physician will inquire about symptoms, smoking history, exposure to environmental and occupational substances, and any family history of cancer. This information aids in understanding potential risk factors and symptoms.
  • Physical Examination: A thorough physical examination is conducted to assess general health and identify any signs of lung cancer or related lung conditions.

Imaging Studies 

Imaging studies play a crucial role in diagnosing lung cancer. They provide detailed insights into the condition. Here are the key imaging tests:

  • Chest X-ray: Often the initial test to identify abnormal areas in the lungs.
  • Computed Tomography (CT) Scan: Offers cross-sectional images of the body, aiding in determining tumour size, shape, and location. It can also detect enlarged lymph nodes possibly containing cancer.
  • Positron Emission Tomography (PET) Scan: Helps identify potential cancer spread to lymph nodes or other body parts. Cancer cells, due to their increased metabolic activity, absorb more of the radioactive sugar used in the PET scan, making tumours visible.
  • Magnetic Resonance Imaging (MRI) Scan: Particularly valuable for assessing the brain and spinal cord in case of suspected metastasis.

Laboratory Tests

  • Sputum Cytology: This test involves examining mucus coughed up from the lungs under a microscope to identify cancer cells.
  • Blood Tests: While not directly used for diagnosing lung cancer, blood tests provide valuable insights into a patient's overall health and organ function.


A biopsy is the definitive method to confirm a lung cancer diagnosis. It involves the removal of tissue for microscopic examination. There are several biopsy techniques:

  • Bronchoscopy: A bronchoscope, a thin, lighted tube, is inserted through the mouth or nose, down the windpipe, and into the bronchi and bronchioles to examine or collect tissue.
  • Needle Biopsy: A needle is inserted through the chest wall into a suspected tumour to extract tissue.
  • Thoracentesis: If there is fluid around the lungs, a needle can be inserted into the chest wall to remove some of the fluid, which is then examined for cancer cells.

Molecular Testing 

When cancer is confirmed, the tissue may undergo molecular testing to identify specific genes, proteins, and other unique factors within the tumour. This aids in determining the type of lung cancer and guides treatment decisions.

Lung Cancer Staging

Once lung cancer is diagnosed, determining its stage is essential. This stage indicates the extent of cancer within the body and its specific location. Staging plays a critical role in shaping treatment strategies and offering insights into prognosis.

Lung Cancer Treatment

Lung cancer treatment is determined by various factors, including the type of lung cancer (non-small cell or small cell), the disease's stage, the patient's overall health, and their preferences.

Here's an overview of the primary lung cancer treatment modalities:


  • Wedge Resection: Removal of a small section of the lung that contains the tumour, along with a margin of healthy tissue.
  • Segmental Resection: Removal of a larger portion of the lung, but not an entire lobe.
  • Lobectomy: Removal of an entire lobe of the lung.
  • Pneumonectomy: Removal of an entire lung.

Lymph nodes in the area may also be removed and tested for cancer.

Radiation Therapy

Uses high-energy beams, such as X-rays or protons, to kill cancer cells. It can be used before surgery to shrink a tumour, after surgery to kill any remaining cancer cells, or as the primary treatment for patients who aren't surgical candidates.

Stereotactic Body Radiotherapy (SBRT)

A high radiation dose is delivered to the tumour over a few treatments. It's used for small tumours.


Chemotherapy involves the use of drugs to kill cancer cells. It can be given before surgery to shrink tumours, after surgery to kill remaining cells, or as the primary treatment. It is a mainstay of lung cancer treatment for small cell lung cancer, which tends to spread early.

Targeted Therapy

Targets specific abnormalities in cancer cells. For example, some non-small cell lung cancers have mutations in the EGFR, ALK, ROS1, or BRAF genes, and drugs targeting these mutations can be effective.


Uses the body's immune system to fight cancer. Drugs like checkpoint inhibitors can help the immune system recognise and attack cancer cells.

Palliative Care

It focuses on providing relief from symptoms and improving the quality of life. It can be used alongside other treatments.

Clinical Trials

Research studies that test new treatments or new ways of using existing treatments. They might offer access to innovative therapies.

Other Treatment Options

  • Radiofrequency Ablation (RFA): Uses electrical energy to heat and destroy cancer cells.
  • Cryotherapy: Uses extreme cold to kill cancer cells.
  • Laser Therapy: Uses a laser beam to kill cancer cells.
  • Photodynamic Therapy (PDT): Uses a drug that gets activated by light to kill cancer cells.

The choice of treatment for lung cancer often involves a multidisciplinary team of medical oncologists, radiation oncologists, thoracic surgeons, pulmonologists, and other specialists. They collaborate to develop a comprehensive treatment plan tailored to the individual patient's needs. Lung cancer can be potentially curable, particularly when detected and treated in its early stages. When in search of specialised care, you should consider consulting one of the best pulmonologists or renowned lung specialists in Delhi, or any other location in India.

Written and Verified by:

Medical Expert Team