An Overview of Lung Cancer Stages

Determining the stage of your lung cancer is one of the most important first steps after you are diagnosed. It can be frustrating to wait during this time, as often several tests are ordered. Some of the time a stage cannot be judged for certain until after surgery, but it is important that lung cancer is accurately staged.

Importance of Lung Cancer Stages

There are a few reasons that defining the stage of your lung cancer is important. One is that determining the stage of your cancer provides essential information for developing a treatment plan. Staging can help you know whether or not surgery is an option for your cancer, and how aggressive to be with other treatments. Another benefit of careful staging is in estimating your prognosis. While cancer treatments are changing and it's impossible to know exactly how you will respond to your treatments, the stage of your cancer may give you some idea of what you can expect.

Tests and Procedures

Several studies are usually done to determine the specific stage of a lung cancer. These studies are done to assess the size of your tumor, and if and where it has spread. Imaging tests can provide a lot of information, but a biopsy is usually needed to know exactly what kind of lung cancer you have, and how it is unique on a molecular level. Some staging tests may include:

Imaging studies - CT scans and MRI scans may help define the size of a lung cancer and how far it has spread. The use of PET scans for lung cancer staging can be particularly helpful in determining whether a lung cancer is operable or not.

Bronchoscopy - A bronchoscopy is a procedure in which a lighted instrument is placed through your mouth and into your bronchi to visualize the large airways of your lungs. This allows doctors to see cancers near your large airways, as well as cancers deeper in the lungs via a procedure known as an endobronchial ultrasound.

Mediastinoscopy - A mediastinoscopy is a procedure that is sometimes used in order to visualize—and biopsy, if appropriate—the area called your mediastinum. The mediastinum is the area between your lungs which contains the heart, the esophagus, the trachea, as well as many lymph nodes. Determining whether or not your cancer has spread to these mediastinal lymph nodes can play a big role in planning treatment.

Lung biopsy reports - After imaging studies are done, lung biopsy is usually needed to determine the exact type of lung cancer you have as well as the molecular profile (genetic characteristics) of your tumor. A lung biopsy can be done in several ways: through a needle biopsy in which a needle is inserted through your chest wall into your lung, a biopsy done during a bronchoscopy, an open lung biopsy (usually during lung cancer surgery), or a video-assisted thoracoscopic biopsy, in which a few incisions are made in your chest and a lighted scope is inserted to obtain tissue. Recently a test called a liquid biopsy became available, which can determine some characteristics of your cancer with a simple blood test.

Surgery reports - Some of the time an accurate stage cannot be determined until after a surgical procedure, such as a lobectomy, has been performed. Learn how to read your lung cancer pathology report.

Tests for Metastases

In addition to tests done to evaluate a lung cancer itself, tests are done to look for metastases (spread) of lung cancer. The most common areas to which lung cancer spreads include the bones, the brain, the liver, and the adrenal glands. These tests may include an abdominal CT scan (to look for liver and adrenal metastases), a bone scan (to look for bone metastases), and a brain CT or MRI scan (to look for brain metastases). Small cell lung cancer can also spread to the bone marrow, and sometimes a bone marrow biopsy is done to look for this spread.

TNM Staging

In order to understand the stage of your lung cancer it's helpful to quickly review something known as "TNM staging." TNM staging is a way of looking at your tumor by evaluating its size as well as how far it has spread. You may have seen this on reports with letters such as T2N2M0. It's actually much easier to understand this than it looks. These letters you will see include:

T - T stands for "tumor" and is a measure of the size of your cancer in centimeters. For example, a cancer which is 3cm (1.5 inches) in diameter would be written "T1.)

N - N stands for lymph "node" involvement. N0 would mean that the cancer has not spread to any lymph nodes. N1 means that a cancer has spread to lymph nodes near the original tumor. N2 means that the tumor has spread to lymph nodes further away from the primary tumor. N3 refers to lymph nodes even further away from the tumor or on the opposite side of the body.

M - M stands for the presence of metastases. M1b means that a cancer has spread to distant regions of the body. M1a means that a cancer has spread to the other lung, or into the space between the layers lining the lungs (malignant pleural effusion).

These different TNM staging combinations, in turn, correspond to specific numeric stages (number stages) of lung cancer.

Staging of Different Types of Lung Cancer

For the two most common types of lung cancer, staging is quite different

Non-small cell lung cancer is broken down into five stages: stage 0 to stage IV, with subcategories in which these are narrowed down further. Small cell lung cancer is broken down into only two stages: limited stage and extensive stage.

Non-Small Cell Lung Cancer Stages

Non-small cell cancer is broken down into five stages, ranging from stage 0 to stage IV. Each of these stages is further broken down into substages. Let's take a look at each of these stages as well as some common treatments.

Stage 0 Lung Cancer

A diagnosis of stage 0 non-small cell lung cancer is fairly rare, but will likely become more common now that lung cancer CT screening is more widespread. In stage 0 lung cancer—also carcinoma in situ—the cancer is isolated within the few layers of cells in which it began and has not spread beyond the inner lining of the lungs. These tumors may be suspected based on a study of your sputum (sputum cytology) but a cancer is not detectable on imaging studies we currently have. Since these tumors are so small, they are usually discovered on screening and they rarely have any symptoms.

Treatment for stage 0 lung cancer - The treatment of choice for stage 0 lung cancer is surgery, with the type of surgical procedure depending on the location of the cancer.

Prognosis for stage 0 lung cancer - Since stage 0 lung cancer, or carcinoma in situ, is considered non-invasive, these cancers should, in theory, be 100 percent curable with treatment.

Stage I Non-Small Cell Lung Cancer (NSCLC)

Stage I non-small cell lung cancer includes tumors which are invasive (all stages excepting stage 0 are considered invasive), but which have not spread to any lymph nodes. The term "invasive" can be frightening, but this does not mean that a cancer has invaded any tissues outside of the lungs. It simply means that it has spread beyond the top layer of cells lining the airways. Roughly 15 percent of people are diagnosed at this stage. It is further broken down into:

Stage Ia lung cancer - These tumors are less than 3cm (1.5 inches) in diameter.

Stage Ib lung cancer These tumors are larger than 3cm in diameter.

Treatments for stage I lung cancer - Lung cancer surgery is the treatment of choice for stage cancers. For people who have stage I lung cancer but are unable to have surgery, or for those who have tumors that are unable to be reached by surgery, stereotactic body radiotherapy (SBRT) may be used to treat the cancer. With stage Ia lung cancer, surgery may be the only treatment needed. For stage Ib lung cancer or those with aggressive features, oncologists may recommend adjuvant chemotherapy (chemotherapy designed to treat any cancer cells which have spread beyond the lungs but can not yet be detected on imaging studies).

Prognosis for stage I lung cancer - The prognosis for stage I lung cancer is relatively good, with roughly half of people diagnosed being alive five years after diagnosis. This prognosis is somewhat better if the cancer is found during a screening test for lung cancer.

Stage II Non-Small Cell Lung Cancer

Stage II non-small cell lung cancers include several variations. These cancers, which are considered "localized" cancer, may be small but already have spread to nearby lymph nodes, or may be larger than stage I cancers. These tumors may also have invaded the airway or the lining of the lung (the pleura).

Stage IIa lung cancer - These tumors are often between 3 and 7cm and have spread to nearby lymph nodes.

Stage IIb lung cancer - These cancers are often between 5 and 7cm and have spread to nearby lymph nodes, or have not spread to lymph nodes but are quite large (greater than 7cm).

Treatments for stage II lung cancer - Treatments for stage II most commonly include a combination of local and systemic treatments. Lung cancer surgery (a local treatment) is often one if the tumor is operable. Adjuvant chemotherapy (a systemic treatment) is often done as well. Further treatments may be recommended based on the molecular profile of your tumor.

Prognosis of stage II lung cancer - Though surgery is often successful, between 20 and 50 percent of these tumors recur. Even if they do recur, however, treatments are available. The five-year survival rate for stage II is around 30 percent but is likely increasing with the approval of new treatments.

Stage III Non-Small Cell Lung Cancer

Stage III non-small cell lung cancer includes a widely varying group of cancers. In fact, stage IIIa lung cancer is often referred to as an "early stage" lung cancer whereas stage IIIb non-small cell lung cancer is often referred to as "advanced stage." Stage III is broken down into:

Stage IIIa non-small cell lung cancer - These cancers are either large and have spread to nearby lymph nodes (N!) or small and have spread to distant lymph nodes (N2.) They may also be referred to a "locally advanced" lung cancer.

Stage IIIb non-small cell lung cancer - These cancers can be of any size, but have spread to distant lymph nodes (N2) or structures near the lungs such as the heart or esophagus.

Treatments for stage III lung cancer - The treatments for stage IIIa and IIIb lung cancers are very different. For stage IIIa lung cancer, surgery may be done with a "curative intent"—medical lingo which simply means the intention to cure the cancer. This is often done along with both chemotherapy and radiation therapy.

In contrast, treatments for stage IIIb lung cancers are similar to those for stage IV cancers, and are usually done in order to improve symptoms or extend life, but are unable to cure the cancer. They are most often treated with a combination of chemotherapy and radiation therapy. Some of the time, treatments such a chemotherapy may decrease the size of a stage IIIb tumor, so that surgery can be done at a later date. Molecular profiling (gene testing) is very important for tumors at this stage, since targeted therapies may be one of the best treatments (see stage IV lung cancer).

Prognosis of stage III lung cancer - The prognosis for stage IIIa and IIIb lung cancers are very different. In contrast to an average five-year survival of 20 percent for stage IIIa, the survival rate for stage IIIb is only around 5 percent. As noted earlier, however, these statistics do not take into account the many new treatments now available for lung cancer.

Stage IV Non-Small Cell Lung Cancer

Stage IV non-small cell lung cancer is the most advanced stage of non-small cell lung cancer. Even so, roughly 40 percent of people have stage IV disease at the time of diagnosis. These tumors have spread to other organs of the body, to the other lung, or to the space between the tissues lining the lungs (malignant pleural effusion).

Treatments for stage IV lung cancer - Though stage IV lung cancer isn't curable, treatments designed to lengthen life and reduce symptoms have improved dramatically in the past few years. Since stage IV lung cancer—also called metastatic lung cancer—has cancer spread beyond the lungs, surgery is rarely done. Treatments which are used may include:

  • Chemotherapy
  • Targeted therapies - Treatments are available for people who bear tumors with several genetic mutations including EGFR mutations, ALK rearrangements, and ROS1 rearrangements, with further medications being studied in clinical trials. Contact your oncologist for an updated list of mutations.
  • Immunotherapy - Two immunotherapy drugs have now been approved for people with lung cancer. While these medications do not work for everyone, for some people they have resulted in long-term survival even for those with the most advanced stages of the disease.

Prognosis of stage IV lung cancer - The prognosis of stage IV lung cancer is improving. While the five-year survival rate was once only 1 to 2 percent, this is changing with the recent approval of new medications, both targeted therapies, and immunotherapy, to treat the disease.

Small Cell Lung Cancer Stages

As noted above, small cell lung cancer is broken down into only two stages;​ limited stage small cell lung cancer and extensive stage small cell lung cancer. These cancers are divided into categories based on whether or not the cancer would be treatable using one field of radiation or not.

Limited Stage Small Cell Lung Cancer

Roughly a third of people are diagnosed in the earliest stage of small cell lung cancer, known as limited stage lung cancer. These tumors are present in only one lung but may have spread to lymph nodes.

Treatments for limited stage small lung cancer - On rare occasions, surgery for small cell lung cancer is an option, but treatment is usually a combination of chemotherapy and radiation therapy.

Prognosis for limited stage lung cancer - The five-year survival rate for limited stage lung cancer is 30 percent to 40 percent. It is higher when these tumors are discovered very early and when surgery can be done.

Extensive Stage Small Cell Lung Cancer

Nearly two-thirds of people diagnosed with small cell lung cancer have extensive stage disease. These cancers may be present in both lungs and have often spread to other regions of the body, even at the time of diagnosis. They commonly spread to the brain.

Treatments for extensive stage lung cancer - Though small cell lung cancer tends to be an aggressive cancer, it often responds well to a combination of chemotherapy and radiation therapy.

Prognosis of extensive stage lung cancer - The five-year survival rate for extensive stage small cell lung cancer is only around 2 to 8 percent, but it's expected that this will be improving. Whereas it seemed little progress had been made in the treatments for small cell lung cancer for several decades this is now changing. Many clinical trials are in progress evaluating these potentials advances in therapy.

Does the Stage of Lung Cancer Ever Change?

The stage you are given for your lung cancer may change over time, especially when further tests reveal new information. That said, the stage of your cancer usually represents the stage at diagnosis. For example, even if you have surgery for stage IIIa lung cancer and currently have no evidence of cancer, your cancer would still be called stage IIIa (although this would include a description such as NED, which stands for no evidence of disease).

It's not uncommon for the stage of lung cancer to be raised when new information is found. For example, if it's noted after your initial diagnosis that lymph nodes are affected on a PET scan. If a cancer recurs, the stage may increase as well. For example, if a stage II lung cancer recurs and there is evidence that it has spread to bones, it would now be considered a stage IV lung cancer.

Your Next Step After Your Lung Cancer Is Staged

Once you and your doctor figure out an accurate stage for your cancer, lung cancer treatment options will be discussed. This is a time when many people consider how to choose the best lung cancer treatment center It is also a time when you may wish to pursue a second opinion for your lung cancer. It's important to understand that getting a second opinion will not upset the doctor you have been seeing, and in fact, getting a second opinion is expected. These opinions may provide you with different options for treatment, or instead, may simply make you feel more confident about the treatment approach you choose. Keep in mind that there are many factors in addition to the stage that go into selecting the best treatments.

A Word From Verywell

It's important to understand that everyone is different. There are not two stage III cancers that are alike, and everyone responds differently to treatment.

It can't be stressed enough that the treatments—and survival rates—for lung cancer are improving. Keep in mind that any statistics you read about your prognosis are a few years old. While these numbers can give you a rough estimate about how people do statistically, they don't tell us much about how you will respond as an individual. And considering that there were more new treatments for lung cancer approved in the period between 2011 and 2015 than in the 40-year period prior to 2011, these may not be very helpful.

Take time to learn how to find good cancer information online. Let your family and friends help you in your journey. The fact that you are reading this information shows that you have taken a big step in being an active participant in your care. Learn how to be your own advocate in your health care. Those who are surviving and living with lung cancer will tell you that it makes a big difference. And nobody is more motivated than those living with this disease.

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