The stages of lung cancer range from 0 to 4 based on how advanced the cancer is. Lower numbers are less advanced and have a higher survival rate. Higher stages are more advanced and have a lower survival rate.

There are different lung cancer classification systems based on the type of cancer. Information used in staging lung cancer includes the size of the main tumor, cancer in the lymph nodes, and the spread of cancer to other areas of the body. 

The lung cancer staging system lets oncologists (cancer specialists) effectively communicate with and about the patient, make accurate treatment decisions, and determine the course of the disease.

This article will review the stages of types of lung cancer, including life expectancy and survival rates at each stage. It will review the symptoms and treatment options for each lung cancer stage and how quickly it progresses.

Understanding the Stages of Lung Cancer 

Different types of lung cancer use different staging systems. The two main types of lung cancer are non-small cell lung cancer (NSCLC) and small cell lung cancer (SCLC). There is also a type of cancerous tumor that can develop in the lungs called a carcinoid tumor. Characteristics of each include:

• NSCLC is the most common type of lung cancer, making up 80% to 85% of lung cancers in the United States.
• SCLC makes up 10% to 15% of lung cancer cases in the United States
• Carcinoid tumors of the lungs make up just 1% to 2% of lung cancers.

Staging Non-Small Cell Lung Cancer

Non-small cell lung cancers are staged on a traditional 0 to 4 system based on the size of the tumor, its presence in the lymph nodes, and its spread to other organs.

The other main factor that impacts the stage of NSCLC is the type of cells the cancer has come from. The three most common kinds of non-small cell lung cancer are:

• Adenocarcinomas develop from the gland cells that make mucus to lubricate the airways. It’s most common in smokers or former smokers but is also the most common type of lung cancer that develops in nonsmokers. These tumors are more likely to be found before spreading to other body parts.
• Squamous cell carcinomas start in the flat cells that line the airways. They’re often linked to a history of smoking. 
• Large cell carcinomas grow and spread quickly and are more challenging to treat. 

Most NSCLCs are diagnosed at stage 3 or 4. According to the National Cancer Institute’s SEER (Surveillance, Epidemiology, and End Results) database, only 26% of lung and bronchus cancers are diagnosed early, with more than half (53%) of cases found after it has already spread to other body parts (metastasized).

Staging and Treatment of Small Cell Lung Cancer 

Small cell lung cancers use a different staging system. This system only has two stages.

Limited SCLC is on just one side of the chest but can be present in both the lung and lymph nodes. These cancers are confined to an area small enough to be treated with radiation through just one port.

About one-third of people with SCLC are classified as limited-stage. They will typically benefit from more aggressive treatment options like chemotherapy combined with radiation to try to cure the cancer. 

Extensive SCLC is typically spread over a larger area—widespread within one side of the chest or on both sides. The cancer may also have spread to lymph nodes above the collar bone, on the other side of the chest, or in the middle of the chest. Cancer may have spread to the fluid around the lung or other body parts and organs.

Extensive-stage SCLC is more advanced, so treatments aim to control the spread of cancer instead of cure it. This would typically involve chemotherapy alone. Two-thirds of small cell lung cancers are classified as extensive stage.

Staging Carcinoid Tumors of the Lung

Carcinoid lung cancers may grow very slowly and are less likely to spread to other body parts than other lung cancers. The staging system used for lung carcinoid tumors is a version of the TNM staging system published by the American Joint Committee on Cancer (AJCC) in 2018, includes:

• Occult (hidden) cancer is when the main tumor can’t be found and hasn’t spread. 
• Stage 0 hasn’t spread beyond the top layers of the airways.
• Stage 1 cancers, including 1A (1A1, 1A2, 1A3) and 1B, carcinoid lung cancers, are smaller and have not spread beyond the lungs.
• Stage 2A and 2B carcinoid lung cancers are larger than stage 1 or have spread to a lymph node.
• Stage 3A, 3B, and 3C carcinoid lung tumors are even larger, or they have spread to multiple lymph nodes or other chest structures or the other side of the chest. 
• Stage 4A and 4B cancers have spread out of the lung to the other lung, the fluid around the lungs or heart, or outside of the chest.

Stage 0 NSCLC

Stage 0 non-small cell lung cancer is the most curable stage of this common lung cancer. Stage 0 is when cancer cells are found only in the topmost layer of cells in the airway lining. They haven't spread deeper into the airway nor are they found in any lymph nodes or other body parts.

Early lung cancers typically have very few symptoms. Most lung cancers do not have symptoms until they spread outside the lungs. This makes it challenging to catch lung cancers early.

Treatment for stage 0 NSCLC typically involves surgery without chemotherapy or radiation. Usually, the small section of the lung that is cancerous is removed using a segmentectomy (removal of a segment of the lung) or wedge resection (removal of a wedge-shaped area of the lung). These treatments should be enough to cure stage 0 NSCLC.

Alternatives to surgery include photodynamic therapy (a light-sensitizing drug and bright light is used to kill cancer cells), laser therapy, or brachytherapy (internal radiation).

It is not often that lung cancers are caught at stage 0. If they are, it’s usually because you’re getting scanned for another reason or getting screening for being high risk. If it is completely removed, stage 0 NSCLC is curable and should not recur, indicating a high survival rate is likely.

Stage 1 NSCLC

Stage 1 non-small cell lung cancer is divided into the following stages:

• Stage 1A (1A1, 1A2, 1A3) tumors are smaller than 3 centimeters (cm) and haven’t invaded deeper lung tissue. Most often, they haven’t reached the lung membranes or central airways or spread anywhere else.
• Stage 1B NSCLCs are either 3 to 4 cm, have grown into the central airway or membranes, or partially block the airway.

Stage 1 NSCLC is typically treated with surgery to remove the area of the lung with the primary tumor. The surgeon will also check the lymph nodes and the space between the lungs for cancer.

Certain factors may make stage 1 NSCLC more likely to return after surgery. In these cases, the person may get additional treatment with chemotherapy and possibly immunotherapy after surgery.

If analysis of the removed portion of the lung after surgery suggests that there may have been cancer left behind, you may need another surgery or radiation. 

Immunotherapy with Opdivo (nivolumab) is another option for larger tumors. It is used along with chemotherapy before surgery. Additional therapy after surgery might be needed depending on what is found at the time of surgery.

People with serious health problems who can’t have surgery may get radiation therapy, including stereotactic body radiation therapy (which delivers precise and intense doses of radiation to the cancer site) or radiofrequency ablation treatment (radio waves apply heat to destroy tissues).

About 26% of adenocarcinomas of the lung and bronchus are found at the localized stage. The localized stage is the National Cancer Institute’s SEER database equivalent to stage 1 or stage 0 cancers. These cancers have not spread beyond the tissue or organ they started in (the primary site).

Stage 2 NSCLC

Stage 2 non-small cell lung cancer is larger tumors that may have spread within the lung area or to one or more lymph nodes, as follows:

• Stage 2A NSCLC tumors are 4 to 5 cm across. They’ve either grown into the central airway and the membranes around the lungs or they partially block the airway. 
• Stage 2B NSCLC tumors are either 5 to 7 cm or have spread to at least one lymph node on the same side of the chest. A tumor may also have grown into the central airway, the membranes around the lungs, or partially blocked the airway.

Most early-stage lung cancers do not have symptoms. Lung cancer symptoms that may crop up for stage 2 and other early-stage cancers include:

• Cough that sticks around and continues to get worse
• Bloody or rust-colored spit or phlegm from a cough
• Pain in the chest when deep breathing, coughing, or laughing
• Hoarseness
• Lack of hunger
• Losing weight without a reason
• Loss of breath
• Tiredness or weakness
• Recurrent bronchitis or pneumonia
• Wheezing that wasn’t present before

Treatment for stage 2 NSCLC includes surgery, which might consist of removing the whole lung and any lymph nodes that may have cancer.

After surgery, the tissues removed are checked for cancer. If some were left behind, you may need another surgery and then treatment with a combination of chemotherapy, immunotherapy, and radiation.

Chemo and/or immunotherapy may be recommended after surgery even if they believe all of the cancer was removed.

For larger tumors, treatments before surgery may include immunotherapy with Opdivio and chemotherapy. People who can’t have surgery may only get radiation.

Stage 3 NSCLC

Stage 3 non-small cell lung cancers have spread to more lymph nodes and further areas within the chest cavity. They may also be larger. These stages include:

• Stage 3A lung tumors may still be small but have spread to lymph nodes around where the windpipe splits or in the space between the lungs on the same side of the lung.
• Stage 3B lung tumors are a bit larger and may have also grown into the central airway and the membranes around the lungs or they partially block the airway. 
• Stage 3C lung tumors are large and spread to other structures of the lungs, potentially with two or more nodules and lymph nodes near the collarbone or on the other side of the body. They may also have infringed on the heart or other structures in the chest, like the esophagus, diaphragm, or spine.

Treatment of stage 3 lung cancers includes a mix of radiation, chemotherapy, and surgery. Immunotherapy with Opdivo, Keytruda (pembrolizumab), Imfinzi (durvalumab), or Libtayo (cemiplimab), or targeted treatment with Tagrisso (osimertinib) may be an option for some stage 3 lung cancers.

These cancers can be hard to treat, so taking part in a clinical trial of newer treatments may be a good option for some people.

About 19% of adenocarcinomas of the lung and bronchus are found at the regional stage. The regional stage is the National Cancer Institute’s SEER database equivalent to stage 2 or stage 3 cancers. These cancers have spread to lymph nodes and other tissues within the organ they developed in but have not spread to far reaches of the body.

Stage 4 NSCLC

Stage 4 non-small cell lung cancers are the most advanced and have the worst survival rate. Stage 4 lung cancers are challenging to cure. These cancers can be any size and may be present in any number of lymph nodes in any part of the body.

The defining trait of stage 4 lung cancers is that they’ve spread beyond the lungs to other organs. They include:

• Stage 4A lung cancers are either in both lungs, the fluid around the lungs, or the fluid around the heart. Or it may have spread outside the chest to the brain, liver, bones, or another organ.
• Stage 4B lung cancers have become tumors in other parts of the body, including in faraway lymph nodes or organs.

When lung cancer spreads to other parts of the body, it leads to more detectable symptoms, such as:

• Lung cancer in the bones may cause bone pain in the back or hips.
• Lung cancer in the brain can cause headaches, weakness or numbness of an arm or leg, dizziness, balance problems, or seizures.
• Lung cancer in the liver can cause the eyes and skin to turn yellow.
• Lung cancer that has spread to the visible lymph nodes in the neck or above the collarbone can cause them to swell up.

Treatment for stage 4 lung cancers can include surgery, chemotherapy, targeted therapy, multiple immunotherapy options, radiation therapy, photodynamic therapy, or laser therapy. These treatments are intended to help you live longer and relieve symptoms. 

Genetic analysis of the tumor before any treatment can refine treatment choices, including the use of targeted treatments, including:

• Lumakras (sotorasib) or Krazati (adagrasib) for a KRAS G12C gene change 
• Anaplastic lymphoma kinase (ALK) inhibitors for tumors that have the ALK gene change
• Epidermal growth factor receptor (EGFR) inhibitors for changes in the EGFR gene
• Xalkori (crizotinib), Rozlytrek (entrectinib), or Zykadia (ceritinib) for changes in the ROS1 gene
• Tafinlar (dabrafenib) with Mekinist (trametinib) for a change in the BRAF gene
• Retevmo (selpercatinib) or Gavreto (trametinib) for changes in the RET gene
• Tabrecta (lapatinib) or Tepmetko (lapatinib) for changes in the MET gene
• Vitrakvi (larotrectinib) or Rozlytrek (entrectinib) for a change in the NTRK gene

About 51.9% of adenocarcinomas of the lung and bronchus are found at the distant stage. The “distant” stage is the National Cancer Institute’s SEER database equivalent to stage 4 cancers. These cancers have spread to far away lymph nodes and other organs.

Factors Influencing Success of Early-Stage Treatment 

Early-stage lung cancer usually refers to stages 1, 2, and 3A NSCLC and limited-stage SCLC.

Factors influencing the success of these treatments include the tumor's location, how much it has grown or spread, and where it is located in the lung—other factors like proteins the cancer is making or the genetic changes that may also play a role.

What options are suitable for your cancer depends a lot on the size of the tumor, its location, what lymph nodes it has spread to, how healthy you are, and how treatment progresses.

Factors Influencing Success of Late Stage Treatment 

Treatment for late-stage lung cancer, including stage 3B and stage 4 lung cancers, is determined by multiple factors. The treatment for your cancer is likely to be determined by your desires as much as where and how far the cancer has spread, whether the cancer cells have certain gene or protein changes, and your overall health.

Your health, treatment goals, and how you react to treatments play a significant role in what treatments are tried for late-stage lung cancer.

Summary

Cancer doctors classify lung cancer from stages 0 to 4 based on how large it is and how it has spread. Types of lung cancer use different staging systems. An oncologist determines the cancer's stage by its size, lymph nodes, and spread. Also significant are the type of cancer and any protein or gene changes.

Non-small cell lung cancers (NSCLC) include adenocarcinomas, squamous, and large cell carcinomas. Oncologists stage small cell lung cancers (SCLC) as a limited or extensive stage. Carcinoid tumors of the lung follow a basic TNM staging system based on tumor size, lymph node involvement, and metastasis.

The distinct stages of NSCLC have varying survival rates and treatment approaches. A surgeon could cure stage 0 NSCLC. But an oncologist would treat advanced NSCLC with a mix of:

• Surgery
• Chemotherapy
• Radiation
• Immunotherapy
• Targeted therapy
• Other treatments to relieve symptoms

Factors influencing treatment success include where the tumors are and how early they're found.