Lung Cancer

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The uncontrolled division of cells in the lungs leads to lung cancer. The formation of tumours in the lungs affects various pulmonary functions, including breathing.

Lung cancer is the most common cancer that leads to death worldwide. According to 2020 GLOBOCAN data, it is the 4th most common cancer in Indians.

Lung cancer is more common in smokers, although it can also strike non-smokers. Passive smoking or second-hand smoking is also a risk factor for lung cancer

Quitting smoking can help in reducing one’s lung cancer risk.


Based on the appearance of malignant cells under a microscope, there are two primary forms of lung cancer:

1. Non-small cell lung cancer (NSCLC)

The majority of lung cancer cases are NSCLC. This lung cancer type grows at a relatively slower rate. Following are the subtypes of NSCLC:

  • Adenocarcinoma: Adenocarcinoma is a cancer type that develops in the mucus-producing cells that are present in the lining of the air sacs.
  • Squamous cell carcinoma (SCC): Squamous cell carcinoma (SCC) is a type of cancer that develops in the squamous cells present in the lining of the airways.
  • Large Cell Carcinoma: Large cell carcinoma is a type of lung cancer that develops in large cells in any part of the lung.

2. Small cell lung cancer (SCLC)

SCLC is a type of lung cancer that is more aggressive and more common in smokers. It spreads more quickly to the nearby organs. Due to its appearance being similar to that of oat grains, this cancer is also known as oat cell cancer. SCLCs are often diagnosed in the advanced stages.


In the early stages, lung cancers may not show any major symptoms. It may be missed on X-ray scans too. Therefore, it is important for high-risk individuals to pay close attention to any discomforts related to breathing and those that are related to the chest region. Following are the major symptoms associated with lung cancer:

  • Chronic cough that lasts for more than four weeks
  • Shortness of breath
  • Wheezing
  • Coughing up blood
  • Pain in the chest
  • Tiredness
  • Swallowing difficulties
  • Loss of appetite
  • Unintentional weight loss
  • Swollen arms and face
  • Joint problems


Scientists have identified a few risk factors that are strongly associated with lung cancer development, and they are:

  • Smoking: Smoking is said to be responsible for 80–90 per cent of lung cancer cases. Passive smoking, often known as second-hand smoking, occurs when a person inhales smoke from another person’s cigarette. It is a leading cause of lung cancer in non-smokers. Those who live with smokers have a 20-30% greater risk, while those who are exposed to second-hand smoke have a 16-19% higher risk, compared to non-smokers who are not exposed to such circumstances.
  • Exposure to Radon Gas: Long-term exposure to radon gas, which accumulates in buildings, particularly in basements and other low-lying locations, raises the risk of lung cancer.
  • Exposure to Harmful Chemicals and Pollutants: Long-term exposure to dangerous chemicals and pollutants such as asbestos, arsenic, diesel smoke, carbon monoxide, sulphur dioxide, nitrogen oxides, chromium, silica and others can raise the risk of lung cancer.
  • Lung Cancer in the Family: Those with a family history of lung cancer are more likely to develop the disease.
  • Personal Lung Cancer History: Those who have previously been treated for lung cancer are at a higher risk of developing lung cancer again.
  • Radiation Therapy to the Chest in the Past: Cancer survivors who have received chest radiation therapy are more likely to develop lung cancer.


There are multiple testing methods available for the detection and diagnosis of lung cancer:

Initially, a physical examination and a thorough assessment of the medical history are performed to understand the cause of the symptoms. If any abnormalities are suspected, then additional tests may be recommended.

a. Imaging Tests: A chest X-ray scan may be recommended if an abnormal lump or nodule is suspected. A CT scan of the lungs can identify microscopic lesions that aren’t visible on an X-ray.

b. Sputum Cytology: If a patient has a cough with sputum, it may be collected and examined under a microscope to check for the presence of lung cancer cells.

c. Biopsy: During the biopsy, a tissue sample is collected from the abnormal mass, and it is analysed under the microscope. There are numerous ways that doctors use to collect the biopsy sample.

  • Bronchoscopy: During bronchoscopy, the doctor examines the abnormal regions of the lungs using a specialised tube called a bronchoscope. This tube has a light source and a camera. Even specialised tools can be sent to collect biopsy samples during this procedure. The sample obtained so is sent for further analysis.
  • Mediastinoscopy: This procedure involves making an incision at the base of the neck and inserting surgical equipment behind the breastbone to obtain tissue samples from lymph nodes.
  • Needle Biopsy: During needle biopsy, the doctor guides a needle through the chest wall and into the lung tissue to collect abnormal cells with the help of X-ray or CT images

In the next stage, PET/CT scan may be recommended to determine the extent or stage of the disease. Imaging tests like PET/CT, MRI scans, etc., are used in disease staging, treatment planning and therapy monitoring.


Treatment plans for lung cancers are devised upon considering various factors such as the stage of the disease, exact size and location of the tumour, the patient’s age and the overall condition of the patient. The main treatment options available for lung cancer include surgery, radiation therapy, chemotherapy, immunotherapy and targeted therapy.

a. Surgery: During surgery, the surgeon removes the tumour with a small portion of healthy tissues present around the tumour. Depending on the stage of the disease, there are multiple surgical procedures that doctors opt for, in order to ensure proper management of the disease:

  • Wedge Resection: Wedge resection is recommended for early-stage lung cancers where only the tumour-containing part of the lung is removed along with a margin of healthy tissue.
  • Segmental Resection: Segmental resection removes a larger portion of the lung; however, this procedure does not excise the entire lobe.
  • Lobectomy: Lobectomy removes the entire tumour-affected lobe of the lung.
  • Pneumonectomy: This procedure is performed to operate and remove the entire lung.

If cancer has spread to the nearby lymph nodes, these lymph nodes may be removed as well.

Along with surgery, chemotherapy or radiation therapy or both may be recommended before or after the surgery to ensure that all cancer cells are destroyed. Before the surgery, these treatments can help in shrinking the tumour size, which makes the surgery easier.

b. Radiation therapy: To destroy cancer cells, radiation therapy uses high-powered energy beams from sources such as X-rays and protons.

Radiation may be administered before or after surgery for patients with locally advanced lung cancer. It’s frequently used in conjunction with chemotherapy for better clinical outcomes. If surgery isn’t an option, the primary treatment given may be a combination of chemotherapy and radiation therapy.

Radiation therapy may also help ease symptoms, such as pain in advanced lung cancer cases, which have spread to other organs.

c. Chemotherapy: Chemotherapy is a treatment that uses strong medications to kill cancer cells. Chemotherapy medications can be delivered intravenously (via a vein in your arm) or taken orally. Chemotherapy may be used in combination with radiation therapy for better treatment results. It can also be used to shrink tumours and make them easier to remove before surgery.

Lastly, chemotherapy can be used to treat pain and other symptoms in patients with advanced lung cancer.

d. Targeted Therapy: Targeted medication treatments are designed to target specific vulnerabilities associated with cancer cells. Targeted medication treatments can kill cancer cells by inhibiting these abnormalities.

Targeted therapy for lung cancer is recommended in cases where the disease has progressed to advanced stages, and the patient is not responding to other treatment modalities.

e. Immunotherapy: Immunotherapy is a type of cancer treatment that stimulates the patient’s immune system to fight against cancer. As cancer cells create proteins that assist them to hide from immune system cells, the patient’s immune system fails to recognise cancer cells and attack them. Immunotherapy interferes with the immune system’s natural processes and causes the immune cells to attack the cancer cells.

Just like targeted therapy, immunotherapy is often recommended for those patients who have advanced-stage lung cancers.

Frequently Asked Questions

1. Are lung cancers treatable?

Yes, lung cancers can be treated. We have multiple treatment options available today through which we can ensure to treat the disease successfully and help the patient have a normal and disease-free life.

The earlier the lung cancer is detected, the better is the survival rate and the overall clinical outcome. For this to happen, it is important for one to be mindful about any breathing or lung-related symptom that lasts for more than 2 weeks – any symptom that is bothersome should be brought to the physician’s attention as early as possible.

2. How can smoking cause lung cancer?

Smoking leads to lung cancer by causing cell mutations. Tobacco contains harmful chemicals that have the ability to damage the normal DNA structure and cause mutations, and these chemicals are called carcinogens or cancer-causing substances.

Although the body has numerous cell repair processes in place, a few damages may not be repaired and those damages lead to an uncontrollable division of the cells and eventually tumour growth.

It is very well established that smoking causes the largest percentage of lung cancer cases, and quitting tobacco is found to reduce the risk of developing lung cancer.

3. Why is lung cancer hard to detect?

Lung cancer is one of the challenging cancers to detect because it does not cause any symptoms in the early stages. Therefore, it is important to keep an eye on any symptoms related to breathing and the chest region – this is especially true for high-risk individuals.

4. What are the long-term side effects of lung cancer treatment?

The potential long-term side effects associated with lung cancer treatment include breathing difficulties, poor lung functioning, inflammation, chronic swelling, etc. However, these side effects can be effectively managed with the help of certain medications and lifestyle habits.

At HCG, it is not just the success of the treatment that we care about; our doctors also strive to help the patients have a better quality of life. Our treatment approaches are personalised and patient-centric; these approaches help us ensure that our patients have a better quality of life both during and after the treatment.

5. Can I prevent lung cancer?

Although there are no sure-shot ways to prevent lung cancers, there are a few measures that you can take to reduce your lung cancer risk:

  • Quit smoking (both active/passive)
  • Avoid exposing yourself to harmful chemicals like asbestos, arsenic, carbon monoxide, sulphur, etc.
  • Consider radon testing for your home
  • Ensure to have a balanced and healthy diet that includes fruits and vegetables
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