An Overview of Lung Cancer Stages

In This Article

Lung cancer is staged to describe the severity of the disease and, in turn, direct the appropriate treatment. The staging is based on a series of tests that determine which type of cancer is involved, how big the primary (original) tumor is, and how far the cancer may or may not have spread (metastasized). The staging system varies by whether you have non-small cell lung cancer, which accounts for around 85% of diagnoses, or small cell lung cancer, which accounts for 15%.

Determining the stage of your lung cancer is one of the most important steps following the initial diagnosis. It can be a frustrating process, requiring patience as multiple tests and procedures are performed. But the accurate staging of cancer can not only help you achieve the optimal treatment response but also aid in predicting the likely outcome, known as the prognosis.

Non-Small Cell Lung Cancer

Non-small cell lung cancer (NSCLC) is a group of cancers that behave similarly, the three most common of which are adenocarcinomasquamous cell carcinoma, and large cell carcinoma. These types of NSCLC vary by the part of the lung in which they originate and the speed by which they grow and spread.

Even though each has distinctive features and outcomes, the cancers are all staged in the same way. As a group, NSCLC is broken down into five stages, ranging from stage 0 to stage IV.

Stage 0

Stage 0 NSCLC, also known carcinoma in situ or precancer, is fairly uncommon given that it rarely has any symptoms at this stage. Stage 0 NSCLC is most often spotted on a CT scan during annual lung cancer screening of high-risk individuals.

By definition, stage 0 NSCLC is limited to the lining of the airways and has not spread into the lungs themselves. If left untreated, the precancer can develop into cancer.

Stage 0 NSCLC is typically treated with surgery, such as wedge resection (the surgical removal of a portion of the lung) or sleeve resection (if the tumor is located at the junction where the windpipe enters the lung). No chemotherapy or radiation therapy is needed.

If surgery is not possible due to a person's health or the location of the tumor, a targeted form of radiation called stereotactic body radiotherapy (SBRT) may be used with the intent of curing the disease.

Stage I

Stage I NSCLC is diagnosed when a tumor is invasive but has not spread to any lymph nodes. (All stages of lung cancer are invasive with the exception stage 0.)

Stage I NSCLC is further broken down as:

  • Stage Ia: The tumor is less than 3 centimeters (1¼ inches) in diameter, and the part that has invaded deeper lung tissues is no more than ½ cm (less than ¼ inch) across.
  • Stage Ib: The tumor is larger than 3 centimeters in diameter but not larger than 4 centimeters (just over 1½ inches). Stage Ib cancers must either have grown into on the main airways (bronchus) or the membranes surrounding the lungs (visceral pleura).

For some people with stage Ia NSCLC, lung cancer surgery may be the only treatment needed. Wedge resection is usually only considered if the tumor is very small. Otherwise, a lobectomy (in which one of the lobes of a lung is removed) offers a far better chance of a cure.

For stage Ib lung cancer or those with aggressive features (such as can occur with large cell carcinoma), oncologists may recommend adjuvant chemotherapy. This is a form of chemotherapy given after surgery to help ensure that all cancer cells are killed.

if you have a serious health condition that prevents you from having surgery, SBRT may be used.

Stage II

Stage II NSCLC is a localized cancer that has not spread beyond one lung or the lymph nodes on that side of the lung. The tumors may be larger or smaller than stage I cancer but have already spread to nearby lymph nodes, airways, or visceral pleural tissues.

Stage II NSCLC is broken down as follows:

  • Stage IIa: The tumor is larger than 4 centimeters but not larger than 5 centimeters (2 inches) and has spread to the bronchus or visceral pleura but not nearby lymph nodes.
  • Stage IIb: The tumor is either between 3 and 5 centimeters and has spread to nearby lymph nodes, or between 5 and 7 centimeters (2¾ inches) and has not spread to nearby lymph nodes. The airways or visceral pleura will also be affected.

Treatments for stage II NSCLC typically involves lung cancer surgery followed by chemotherapy. If there are remaining cancer cells after treatment, another round of chemotherapy (or chemotherapy with radiation) may be used.

Stage III

Stage III NSCLC means that the cancer has spread to nearby (regional) tissues. There are both locally advanced and advanced stage III cancers, the latter of which are more difficult to treat.

Stage III NSCLC is broken down as follows:

  • Stage IIIa: The tumor, described as locally advanced, is either smaller than 5 centimeters and has spread to the lymph nodes of the carina (the ridge of cartilage between the lungs); is between 5 and 7 centimeters and has spread to the hilar lymph nodes (where the bronchus enters the lung); or is larger than 7 centimeters and has grown into adjacent organs in the chest (such as the heart or diaphragm) with or without lymph node involvement.
  • Stage IIIb: The tumor, described as advanced, can be of varying sizes and will either have spread to supraclavicular lymph nodes (around the collarbone) or the opposite side of the chest, or manifest with two or more tumors in one or both lungs.

The treatments for stage IIIa and IIIb NSCLC are very different. For stage IIIa, surgery may be performed with the intent to cure the cancer. This is typically accompanied by a combination of chemotherapy and radiation therapy (also called chemoradiation).

By contrast, stage IIIb NSCLC is considered inoperable. Instead of a cure, treatments are focused on extending life and ensuring the best possible quality of life.

Chemoradiation is typically used if you are healthy and strong enough. If control is achieved, the immunotherapy drug Imfinzi (durvalumab) may be used for up to a year to keep the tumor stable. If chemoradiation is not tolerable, the immunotherapy drug Keytruda (pembrolizumab) may be used.

Stage IV

Stage IV NSCLC is the most advanced stage of lung cancer. Also called metastatic lung cancer, it refers to any size and type of NSCLC that has spread from one lung to the other lung, to another part of the body, or to the fluid around the lung or heart.

Stage IV NSCLC is not curable, but it is treatable. Surgery is rarely used unless a tumor is causing major obstruction in the airways or interfering with the function of the heart or other vital organs.

In addition to chemotherapy, radiation therapy, and immunotherapy, there are newer targeted therapies like Xalkori (crizotinib) and Tarceva (erlotinib) that are able to identify and attack cancer cells with specific genetic mutations (such as EGFR mutations, ALK rearrangements, and ROS1 rearrangements). Together, these treatments can help prolong life and allow you a better quality of life.

Clinical trials should also be considered, providing you access to experimental treatments when currently available drugs prove intolerable or ineffective.

Small Cell Lung Cancer

Small cell lung cancer is a less common form of the disease that tends to be more aggressive than NSCLC and far more likely to recur after treatment. There are two major types of SCLC: small cell carcinoma (also known as oat cell carcinoma) and combined small cell carcinoma (in which both small and non-small lung cancer cells are present).

Unlike non-small cell lung cancer, small cell lung cancer is broken known into only two stages: limited-stage SCLC and extensive-stage SCLC.

Limited Stage

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

SCLC that has spread to the supraclavicular lymph nodes or mediastinal lymph nodes (in the center of the chest) may also be considered limited-stage SCLC.

Limited-stage SCLC is often treated aggressively with the aim of curing the disease. This may involve:

  • Chemotherapy alone
  • Chemoradiation to the chest
  • Surgery followed by chemotherapy
  • Surgery followed by chemoradiation
  • SBRT followed by chemotherapy is surgery is not possible

Extensive Stage

Around two-thirds of people diagnosed with SCLC have extensive-stage disease, the more advanced form of small cell lung cancer. With extensive-stage SCLC, tumors may be present in both lungs or have spread to distant parts of the body, most commonly the brain.

Extensive-stage SCLC is not curable and is rarely treated with surgery. Although it tends to spread aggressively, SCLC responds well to chemotherapy (which works by targeting fast-replicating cells).

Among the treatment options for extensive-stage SCLC are:

  • Chemotherapy alone
  • Chemotherapy with immunotherapiy drugs like Opdivo (nivolumab)
  • Chemotherapy followed by radiation therapy to the chest
  • Chemotherapy followed by radiation therapy to head to prevent the spread of cancer to the brain
  • Radiation to the brain, spine, bone, or other parts of the body where cancer has spread as part of palliative treatment (used to reduce symptoms and improve the quality of life)


The staging of lung cancer is used not only to direct treatment but predict the course and outcome of the disease. Key to the prognosis is the survival rate. This is the percentage of people with a disease who are expected to live for a period of time after the diagnosis.

The survival rate is based on everyone with the disease, irrespective of their age and general health at the time of the diagnosis. As such, if you are in good health, your likelihood of exceeding the estimated survival time will be better than people who are in poor health.

Most epidemiologists use five-year survival rates for comparative purposes, which predicts the proportion of people who will live for at least five years following the diagnosis. The more advanced the cancer stage, the lower the survival rate will be.

The five-year survival rate for NSCLC and SCLC following treatmen is as follows:

Non-Small Cell Lung Cancer
  • Stage 0: 100%

  • Stage Ia: 90%

  • Stage Ib: 80%

  • Stage IIa: 65%

  • Stage IIb: 56%

  • Stage IIIa: 41%

  • Stage IIIb: 24%

  • Stage V: 10%

Small Cell Lung Cancer
  • Limited stage: 28%

  • Extensive stage: 6%

A Word From Verywell

It is important to remember that everyone is different and that every cancer is different. While lung cancer staging is an invaluable tool for ensuring a standardized level of care based on our current understanding of the disease, that understanding is changing every day. This is no more true than with survival times.

With the rapid introduction of newer immunotherapies and targeted drugs, you can expect to see survival times increasing for people with NSCLC and SCLC in the coming years. So rather than focusing "how long you have to live," learn as much as you can about your disease and keep appraised of any new developments in treatments.

If in doubt about a treatment plan, do not hesitate to seek a second opinion from an expert in the field. You can do so by reaching out to a specialist at a National Cancer Institute-designated treatment center who is more likely to be updated about the latest treatment options and protocols.

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