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Lung Cancer Stages: Understanding the Progression of the Disease

When we talk about lung cancer, we talk about the two primary types – non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). Each of these types of lung cancer is categorized differently, depending on the severity of the condition and the spread of the tumor.

Given that lung cancer is the leading cause of cancer deaths in the world, getting a confirmed and early diagnosis is key to recovery. Lung cancer stages are determined under the standard TNM classification.

This article will explore the varying lung cancer stages, their significance, and how the disease progresses in the body.

What is the Significance of Lung Cancer Staging?

Understanding and knowing the lung cancer stages is key to a confirmed and comprehensive diagnosis.

Before we discuss the significance of TNM classification or the system of lung cancer staging, let us understand its elements.

T (tumor) – What is the position of the tumor? Has it spread to any other tissues and organs in the nearby region?

N (node) – Has cancer spread to the lymph nodes?

M (metastasis) – Has lung cancer spread to other distant organs like the brain, bones, lungs, etc.?

This is used as the standard form of lung cancer staging. However, when we move to the types of lung cancer, the stages are assigned depending on the type and severity. For example, NSCLC is assigned from Stages 1-4, while SCLC is assigned as limited and extensive.

The significance of Lung Cancer staging is that it helps us understand the following:

  • Where the tumor of the lung cancer cell is located inside or outside of the lungs
  • The size of the tumor
  • Whether the cancer is contained in one place or has spread to other organs

Having a clear idea about the non-small cell lung cancer stages or small cell lung cancer stages allows your lung cancer doctor in India to choose the right treatment plan for the patient.

How is Lung Cancer Staged?

As we mentioned earlier, lung cancer staging depends on the TNM system. During the diagnosis stage, the oncologist will measure the tumors size, explore the tumors location, etc., to stage lung cancer.

The larger the size of the tumor, the more progressive the lung cancer.

Additionally, unlike NSCLC, which has multiple stages of progression (Stages 1-4), SCLC is divided into two stages.

Let us walk you through them in detail:

Small Cell Lung Cancer Stages

SCLC is the rarer lung cancer that affects around 10-15% of the global population and is a more aggressive form of lung cancer. The condition is often diagnosed at a later stage, making treatment difficult in several patients.

Following are the two stages of SCLC:

Limited stage – In this, the SCLC is contained in one lung and possibly in the nearby lymph nodes. Patients diagnosed in this stage don’t have the tumor spread to the other lung or the distant parts of the body, making the condition treatable.

Extensive stage – This is the more advanced stage of SCLC, where the tumor has spread to the other lung, chest cavity, pleura, and even distant organs like the brain. Patients diagnosed in this stage often have poor survival rates.

Non-Small Cell Lung Cancer Stages

Unlike SCLC, NSCLC is the most common type of lung cancer that affects 80-85% of patients globally. Imaging scans like CT-Scans and MRIs help doctors get a more comprehensive and accurate idea about the clinical stage of the NSCLC in the patient.

As mentioned, NSCLC is divided into various stages, ranging from Stages 1-4. It is characterized under the TNM Staging for Lung Cancer AJCC 8th Edition. Let us explore that in detail:

Tx – Presence of tumor in sputum or bronchial washing but not visible in the imaging or bronchoscopy.

T0 – No evidence of tumor yet.

Tis – Carcinoma in situ.

T1 Stage

T1a – the tumor is less than or equal to 1 cm.

T1b – the tumor is larger than 1 cm or less than and equal to 2 cm.

T1c – the tumor is larger than 2 cm but less than or equal to 3 cm.

T2 Stage

T2a – the tumor is larger than 3 cm but less than or equal to 4 cm.

T2b – the tumor is larger than 4 cm but less than or equal to 5 cm.

T3 Stage – the tumor is larger than 5 cm but less than or equal to 7 cm/tumor has spread to the chest wall, pericardium, phrenic nerve, or the satellite nodules of the same lobe of tumor origin.

T4 Stage – the tumor is larger than 7 cm/tumor has invaded the mediastinum, diaphragm, great vessels, heart, trachea, esophagus, or a spine / separate tumor has formed in a different lobe in the ipsilateral lung.

N Stage

N1 – ipsilateral peribronchial or hilar nodes alongside the intrapulmonary nodes.

N2 – ipsilateral mediastinal or subcarinal nodes

N3 – contralateral mediastinal or hilar

M Stage

M1a – the tumor has spread to the contralateral lung

M1b – Single extrathoracic metastasis

M1c – Multiple extrathoracic metastases, where the tumor has invaded one or more vital organs

As confusing as it sounds, understanding the non-small and small cell lung cancer stages is crucial to a patient’s diagnosis. It enables the patient to understand the state of their condition and helps the doctor determine the next step in the treatment.

Dr. Arvind Kumar, a leading chest-onco surgeon at Medanta, prioritizes accurate testing and staging of lung cancer in his patients to ensure that patients are on the right treatment plan to optimize their survival rate.

Does Lung Cancer Staging Determine the Survival Rate?

The survival rate of patients who have lung cancer is determined and classified under four factors:

Localized – 5-year survival rate is 61%. Cancer is contained in the site of its origin.

Regional – 5-year survival rate is 33.5%. Cancer has spread to the nearby lymph nodes.

Distant – 5-year survival rate is 7%. Cancer has spread from the lungs and chest cavity to other vital organs.

Unknown – 5-year survival rate is 10%. Cancer can’t be staged.

Most lung cancer patients’ treatment depends on the stage of the cancer. If the tumor is confined in one space, surgical excision is an effective choice of treatment. Otherwise, chemotherapy, radiotherapy, immunotherapy, targeted therapy, etc., are the latter choices of treatment.


Lung cancer staging is crucial to determine the next course of treatment for the patient. Accurate staging gives the doctor a better idea about the patient’s prognosis and life expectancy with this otherwise deadly disease.

If you are experiencing symptoms that are recurrent and indicate possibilities of lung cancer, don’t refrain from getting medical attention. Earlier diagnosis can potentially save a person’s life and offer a better quality of life. Dr. Arvind Kumar and his team of leading lung cancer specialists can help you navigate the issue.

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What is Stage 4 progressive lung cancer?

Stage 4 lung cancer is the advanced stage where the tumor has spread from its original site in one lung to the other parts of the body.

How does Stage 3 lung cancer progress?

In lung cancer stage 3, the tumor measures over 5 cm and less than 7 cm. In this stage, the tumor might invade the nearby phrenic nerve and the adjoining tissues around the heart.

Can you survive stage 4 lung cancer?

The survival rate of Stage 4 lung cancer is very bleak. However, with advancements in cancer research and treatment, the survival rate is progressively improving.

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