Lung Cancer Stages: What Stages 1 to 4 Mean and Can Lung Cancer Be Cured?
Hearing that lung cancer is “stage III” or “stage IV” can make the stage number feel like a complete prediction of what will happen next. It is not. Cancer stage describes how far the disease has spread; it does not function as a countdown of how long an individual patient will live.
Stage is also different from tumor grade. Stage describes the size and spread of cancer, while grade describes how abnormal the cancer cells appear under a microscope and can provide information about how the cancer may behave.[1]
For non-small cell lung cancer (NSCLC), current classification uses the 9th edition TNM system, which became effective for lung cancer in 2025 and describes the primary tumor, lymph-node involvement, and distant metastasis.[2][3]
If you are looking first for symptoms, risk factors, and how lung cancer is diagnosed, read our complete guide to lung cancer symptoms and early detection.
- Cancer stage is different from tumor grade.
- Current lung cancer staging uses TNM Version 9.
- Stage III is highly heterogeneous and includes both potentially resectable and unresectable disease.
- Stage IV includes IVA and IVB, and not all metastatic lung cancers have the same disease burden.
- A stage can change after surgery when pathology provides more accurate information.
- SCLC is commonly described as limited-stage or extensive-stage disease.
- A 5-year survival rate is not an estimate of how many years an individual patient will live.
- Cancer biology, biomarkers, health status, and response to treatment affect prognosis in addition to stage.
- What does lung cancer stage mean?
- Stage vs grade
- How does TNM work?
- What changed in TNM Version 9?
- Stage 0
- Stage I
- Stage II
- Stage III
- Stage IV
- Stage IVA vs IVB
- How is lung cancer staged?
- Clinical vs pathological stage
- How is SCLC staged?
- Does stage determine treatment?
- What does 5-year survival mean?
- Current lung cancer survival rates
- Saudi lung cancer data
- Why statistics cannot predict one patient's outcome
- Is there hope with stage IV lung cancer?
- Lung cancer staging at Mouwasat Hospital
- Frequently asked questions
What Does Lung Cancer Stage Mean?
Cancer stage describes the extent of disease in the body at the time of assessment.
Staging attempts to answer questions such as:
- How large is the primary tumor?
- Has it invaded nearby structures?
- Are regional lymph nodes involved?
- Which lymph-node stations are involved?
- Is there cancer in the opposite lung?
- Is the pleura or pericardium involved?
- Has cancer spread to a distant organ?
- If distant metastases are present, how many are there and how many organ systems are involved?
Stage is essential for treatment planning and prognosis, but it is not the only information that matters.
What Is the Difference Between Stage and Grade?
| Term | What it describes |
|---|---|
| Stage | The size and extent of cancer and how far it has spread. |
| Grade | How abnormal cancer cells look under the microscope and clues about their biological behavior. |
NCI specifically distinguishes tumor grade from cancer stage.[1]
When people use the phrase “grade 4 lung cancer,” they often actually mean stage IV lung cancer.
How Does the TNM System Work?
| Letter | Meaning | What it describes |
|---|---|---|
| T | Tumor | Primary tumor size and invasion of nearby structures. |
| N | Nodes | Regional lymph-node involvement and the nodal stations affected. |
| M | Metastasis | Distant spread, including the number and distribution of distant metastatic sites. |
T, N, and M are then combined into a stage group such as IA, IIB, IIIA, or IVA.
What Changed in TNM Version 9?
The 9th edition TNM classification for lung cancer took effect in 2025.[2][3]
Important changes include:
- The fundamental T descriptors remained largely unchanged.
- N2 was divided into N2a for a single involved ipsilateral mediastinal/subcarinal nodal station and N2b for multiple involved N2 stations.
- M1c was divided into M1c1 for multiple extrathoracic metastases within one organ system and M1c2 for metastases involving multiple organ systems.
- Some stage-group assignments changed as a result.
The changes provide greater detail about disease burden rather than simply labeling every patient with nodal or metastatic disease in the same way.
What Is Stage 0 Lung Cancer?
Stage 0 refers to carcinoma in situ, where abnormal cancer cells remain highly localized and have not yet developed into more deeply invasive cancer.
It represents the earliest stage and is generally approached with local treatment.
What Is Stage I Lung Cancer?
In stage I NSCLC, cancer remains localized to the lung without regional lymph-node metastasis.
Subgroups within stage I reflect differences in tumor size and local features.
For many medically suitable patients, stage I disease can be treated with curative intent, often with surgery. Effective local treatment can also be considered when surgery is unsuitable.
Because outcomes are generally better when disease is found early, people at sufficiently high risk may benefit from screening before symptoms occur. Read who should have low-dose CT lung cancer screening.
What Is Stage II Lung Cancer?
Stage II includes cancers that are more locally advanced than stage I and may involve a larger tumor, certain local features, or nearby lymph nodes depending on the TNM combination.
Many stage II NSCLCs remain potentially resectable.
However, surgery may be only one component of treatment. Selected patients may require systemic therapy before surgery, after surgery, or both.
For a full explanation of how these choices are made, read our guide to lung cancer treatment.
What Is Stage III Lung Cancer?
Stage III is not one single clinical situation.
It includes IIIA, IIIB, and IIIC disease and can vary substantially in:
- Primary tumor extent.
- Invasion of surrounding structures.
- Lymph-node location.
- Number of involved nodal stations.
- Whether the cancer is surgically resectable.
NCI describes stage IIIA NSCLC as a heterogeneous group ranging from resectable disease to bulky unresectable nodal disease.[4]
This means some patients may undergo surgery as part of multimodality treatment, while others require combinations of chemotherapy, radiation, immunotherapy, or other treatments.
Resectability, nodal pattern, tumor anatomy, lung function, and overall health can significantly change the treatment pathway.
See Lung Cancer Treatment: Surgery, Targeted Therapy and Immunotherapy for the treatment decision pathway.
What Does Stage IV Lung Cancer Mean?
Stage IV means that distant metastatic disease is present.
It does not mean every stage IV cancer has the same disease burden.
Current NSCLC staging divides stage IV into IVA and IVB.[2]
What Is the Difference Between Stage IVA and IVB?
| Classification | Simplified meaning |
|---|---|
| IVA — M1a | May include a separate tumor in the opposite lung, pleural or pericardial tumor nodules, or malignant pleural/pericardial effusion. |
| IVA — M1b | A single extrathoracic metastasis in one organ system. |
| IVB — M1c1 | Multiple distant metastases within a single organ system. |
| IVB — M1c2 | Multiple distant metastases involving multiple organ systems.[2] |
Stage alone cannot determine exactly how many months or years an individual person will live.
How Is Lung Cancer Staged?
Staging usually combines multiple sources of information rather than relying on one scan.
Depending on the clinical situation, assessment may involve:
- Medical history and physical examination.
- Chest and body CT imaging.
- PET/CT.
- Brain MRI when appropriate.
- Lymph-node sampling.
- Bronchoscopy and biopsy procedures.
- Pathology from surgical resection when surgery is performed.[4]
For more on how imaging, biopsy, pathology, and biomarkers fit together, read our complete lung cancer guide.
What Is the Difference Between Clinical and Pathological Stage?
Clinical stage is the best estimate before treatment using imaging, biopsy, lymph-node assessment, and other available information.
When surgery is performed, pathology can examine:
- The entire resected tumor.
- Surgical margins.
- Removed lymph nodes.
- Microscopic disease that may not have been visible on imaging.
This can provide a more precise pathological stage. NCI notes that pathological staging requires examination of the tumor, resection margins, and lymph-node status.[4]
Not necessarily. Pathology can reveal microscopic nodal involvement that could not be seen clearly before surgery, giving the team more accurate information.
How Is Small Cell Lung Cancer Staged?
Although TNM information can also be used, SCLC is commonly described using two practical clinical categories:
Limited-stage SCLC
Cancer remains within a limited chest region and may involve nearby mediastinal or supraclavicular lymph nodes.[5]
Extensive-stage SCLC
Cancer has spread beyond the limited-stage region to other parts of the body.[5]
This distinction is important because treatment planning for SCLC differs substantially from NSCLC.
See our lung cancer treatment guide for the differences between NSCLC and SCLC treatment.
Does Stage Alone Determine Lung Cancer Treatment?
No.
Treatment decisions also depend on:
- NSCLC versus SCLC.
- Histologic subtype.
- Resectability.
- Lung and heart function.
- Performance status.
- Other health conditions.
- Actionable molecular alterations.
- Immune biomarkers such as PD-L1 when clinically relevant.
This is why two patients described as having “stage IV NSCLC” may receive completely different systemic treatments.
Read Lung Cancer Treatment: How Doctors Choose Between Surgery, Targeted Therapy and Immunotherapy for the full treatment decision map.
What Does a 5-Year Survival Rate Mean?
A 5-year relative survival rate does not mean a patient will live for only five years.
Relative survival compares survival among people with a particular cancer with survival among similar people in the general population who do not have that cancer.[1][6]
It is not:
- An expiration date.
- A prediction of one person's exact life expectancy.
- The same as a cure rate.
What Are the Current Lung Cancer Survival Rates?
The American Cancer Society currently reports SEER survival data using localized, regional, and distant disease rather than direct AJCC stage I–IV categories.[6]
| SEER stage | NSCLC 5-year relative survival | SCLC 5-year relative survival |
|---|---|---|
| Localized | 67% | 34% |
| Regional | 40% | 20% |
| Distant | 12% | 4% |
| All SEER stages combined | 32% | 9% |
The current NSCLC figures are based on people diagnosed from 2015 through 2021, while the SCLC figures use patients diagnosed from 2012 through 2018.[6]
Localized, regional, and distant disease are not exact equivalents of stages I, II, III, and IV. They are different classification systems used for different purposes.
What Do Saudi Lung Cancer Data Show?
Local data provide important context.
The Saudi Cancer Registry 2023 recorded 666 newly diagnosed lung cancer cases among Saudi nationals. More than half—56.8%—were diagnosed with distant-stage disease, while approximately 30.6% were localized at diagnosis.[7]
The Saudi Health Council also states that 5-year survival may reach approximately 70% when lung cancer is detected and treated early and falls to around 30% when disease has reached the lymph nodes.[8]
These local figures should not be combined mathematically with the SEER table because the populations, sources, and staging frameworks differ.
For people at increased risk, screening before symptoms appear can be important. Read our LDCT lung cancer screening guide.
Why Can't Survival Statistics Predict One Person's Outcome?
NCI explains that prognosis is affected by factors including cancer type, stage, grade, tumor characteristics, age, general health, and treatment response.[1]
For lung cancer, additional factors may include:
- NSCLC versus SCLC.
- Histologic subtype.
- Pattern and volume of metastatic disease.
- Performance status.
- Actionable molecular alterations.
- Immune biomarkers.
- Response and tolerance to treatment.
Survival statistics also necessarily look backward because several years are required to calculate long-term outcomes.
ACS specifically notes that people diagnosed today may have a better outlook than historical survival numbers indicate because treatment continues to improve.[6]
Patients with the same stage can have different tumor biology, disease burden, health status, treatment options, and responses. An individualized prognosis therefore requires an individualized clinical assessment.
Is There Hope With Stage IV Lung Cancer?
Yes, treatment options exist, although stage IV remains advanced cancer.
Treatment commonly aims to:
- Control cancer for as long as possible.
- Extend survival.
- Reduce symptoms and complications.
- Maintain quality of life.
Some patients experience prolonged responses to targeted therapy, immunotherapy, or other modern treatments when the biology of their cancer makes those treatments effective.
To understand why molecular testing can dramatically change stage IV treatment, read our lung cancer treatment guide.
A published Mouwasat Hospital Madinah stage IV lung cancer case describes the use of biopsy, genetic and immune testing, multidisciplinary review, and personalized systemic treatment, followed by a major clinical response.[9]
One patient's response is not a survival estimate or cure rate for other patients with stage IV disease.
Lung Cancer Staging at Mouwasat Hospital
Lung cancer staging can require collaboration among Pulmonology, Radiology, Pathology, Oncology, and Chest Surgery.
The Pulmonology Department at Mouwasat Hospital lists lung cancer diagnosis and staging in collaboration with Oncology, along with bronchoscopic biopsy procedures in appropriate patients.
The Oncology Department treats both NSCLC and SCLC, while the Chest Surgery Department can participate in assessment of surgically resectable disease.
Multidisciplinary review allows the team to combine:
- Disease stage.
- Pathology.
- Resectability.
- Molecular and immune biomarkers.
- Lung function.
- Overall patient health.
Frequently Asked Questions About Lung Cancer Stages
What is the most advanced stage of lung cancer?
Stage IV is the most advanced stage because distant metastasis is present. However, stage IV itself includes different patterns and amounts of metastatic disease.
Is grade 4 lung cancer the same as stage 4?
No. Stage describes how far cancer has spread, while grade describes how abnormal the cells appear under a microscope. People saying “grade 4” often mean stage IV.
Can stage I lung cancer be cured?
Many stage I NSCLCs can be treated with curative intent, particularly when the cancer is localized and effective surgery or another definitive local treatment is possible.
Can stage II lung cancer be cured?
Some stage II cancers can be treated with curative intent. Treatment may include surgery plus systemic therapy before or after surgery depending on the individual cancer.
Is stage III lung cancer treatable?
Yes. Stage III is highly heterogeneous. Some cancers are approached with surgery as part of multimodality treatment, while others are treated with combinations of chemotherapy, radiation, immunotherapy, or other strategies.
Does stage IV mean someone will die soon?
No exact time can be determined from stage alone. Stage IV means distant disease is present, but it does not provide an individual life expectancy.
How long can someone live with stage IV lung cancer?
There is no single answer. Tumor subtype, biomarkers, metastatic pattern, overall health, and treatment response can lead to substantially different outcomes.
Can lung cancer stage change after surgery?
Yes. Surgical pathology can reveal microscopic tumor or lymph-node findings that were not visible before surgery, leading to a more accurate pathological stage.
Does a 5-year survival rate mean I have five years to live?
No. It is a population statistic, not a time limit for an individual patient.
Does finding lung cancer earlier improve outcomes?
In general, localized lung cancer has substantially better outcomes than distant disease, which is why appropriate screening of higher-risk people can be valuable.
Final Thoughts: Stage Describes the Disease, Not the Patient's Entire Future
Lung cancer stage is essential because it describes disease extent and helps guide treatment, but the stage number alone cannot answer every question about treatment or survival.
Stages I through IV are not simply four levels of severity. Stage III and stage IV in particular contain very different clinical patterns.
Prognosis also depends on cancer subtype, biomarkers, disease burden, general health, and response to treatment.
Within this lung cancer cluster:
- Lung Cancer: Symptoms, Risk Factors and Early Detection explains symptoms, risk, and diagnosis.
- Lung Cancer Screening and LDCT explains who may benefit from screening.
- Lung Cancer Treatment explains how stage, biomarkers, surgery, targeted therapy, and immunotherapy shape treatment decisions.
Medical disclaimer: This article is intended for general health education. An individual's prognosis should be discussed using their specific diagnosis, stage, tumor biology, general health, and treatment response rather than population statistics alone.
Medical References
- National Cancer Institute — Understanding Cancer Prognosis
- International Association for the Study of Lung Cancer — Staging Cards in Thoracic Oncology, 9th Edition
- IASLC — Lung Cancer TNM Classification, 9th Edition
- National Cancer Institute — Non-Small Cell Lung Cancer Treatment and Staging
- National Cancer Institute — Small Cell Lung Cancer Stages and Treatment
- American Cancer Society — Lung Cancer Survival Rates
- Saudi Health Council — Saudi Cancer Registry 2023
- Saudi Health Council — Lung Cancer
- Mouwasat Hospital — Published Stage IV Lung Cancer Case