What Are the Stages of Lung Cancer?

The days following a lung cancer diagnosis can be overwhelming. You will likely have many questions about the severity of your lung cancer, what treatment options are available, and the efficacy of those treatment options. Cancer staging can help your oncologist answer these questions.

Staging is the process of determining how much cancer is in a person’s body and its exact location. Doctors use this information to create a cancer treatment plan — a roadmap that lays out the expected path to recovery. This roadmap may incorporate immunotherapy, surgery, chemotherapy or radiation therapy.

When a patient is initially diagnosed with lung cancer, their oncologist will provide information regarding the lung cancer type. There are two general types of lung cancer: small cell lung cancer (SCLC) and non-small cell lung cancer (NSCLC). Within these classifications, there are various subtypes like small cell carcinoma, a highly malignant form of SCLC, and adenocarcinoma, a common type of NSCLC. The type of cancer determines which lung cancer treatment options will be most effective. For a detailed guide, download our Lung Cancer eBook.

Some lung cancers are detected during preventative lung cancer screenings. However, most cancers are found when they start causing symptoms. If your health has declined suddenly or you are experiencing symptoms that suggest lung cancer, your doctor will likely recommend an imaging test.

Common diagnostic imaging tests include:

• Chest X-ray
• CT scan
• MRI scan
• PET scan
• Bone scan

If an imaging test reveals potentially cancerous lesions or other abnormalities, your oncologist will order a lung biopsy. During this procedure, a small sample of lung tissue is collected using a needle. If fluid has pooled around the lungs, doctors may test this for cancer. A sample of sputum (mucus coughed up from the lungs) can also be tested.

If lung cancer is detected, more tests are needed to accurately stage the disease. To determine if the lung cancer has spread within the chest, doctors may recommend an endobronchial ultrasound or endoscopic esophageal ultrasound to visualize nearby lymph nodes. A mediastinotomy or thoracoscopy may also be done to see if the cancer has spread to the space between the lungs.

Though cancer is typically staged before any treatment is offered, it can also be staged during and after treatment. When cancer is staged after treatment, it is referred to as “re-staging.”

A patient’s clinical stage is an estimate of the lung cancer’s severity based on diagnostic imaging tests and biopsies. This information helps doctors determine the most appropriate cancer treatment plan.

If surgery is the first cancer treatment, then doctors can also determine the pathological stage (also called the surgical stage). This cancer stage is based on previous diagnostic imaging tests and biopsies as well as new information gathered during surgery. Pathological staging is often more accurate than clinical staging.

Post-therapy staging helps measure the cancer’s response to treatments other than surgery such as chemotherapy or radiotherapy.

Staging may also occur if the cancer returns or progresses. Retreatment staging allows doctors to make decisions about future treatment options.

There are many different systems for staging lung cancer. However, the most widely used method for staging NSCLC is the TNM classification system, officially known as the TNM classification system of malignant tumors.

With the TNM system, doctors can systematically describe the cancer’s severity using three different categories:

• T describes the primary tumor.
• N indicates if the cancer has spread to nearby lymph nodes.
• M stands for metastasis. Has the cancer spread (metastasized) to other parts of the body?

The first step in staging lung cancer is to analyze the primary tumor, or where the cancer originated. Doctors will consider the tumor’s size, location, and whether or not it has spread.

They will then assign the T category a letter or number:

• TX means the tumor cannot be measured.
• T0 means the primary tumor cannot be found.
• Tis means the cancer cells have not grown into deeper tissues.
• Numbers after the T (T1, T2, T3, T4) describe the tumor’s size and whether or not it has spread. The higher the number, the more severe the case.

Lymph nodes are small structures that help the body fight disease and infection. Lung cancer often spreads to nearby lymph nodes before metastasizing to other areas of the body.

The N category can be assigned a letter or number:

• NX means the nearby lymph nodes cannot be evaluated.
• N0 means the lymph nodes do not contain cancer.
• Numbers after the N (N1, N2, N3) describe the size, location, and the number of lymph nodes affected by cancer. The higher the number, the more severe the case.

When lung cancer progresses, it often spreads to other parts of the body. This is called metastasis. Lung cancer frequently metastasizes to the nervous system, bones, liver, and adrenal glands first. When this happens, a more aggressive cancer treatment plan is needed.

The M category is assigned a number:

• M0 means no distant cancer has been found.
• M1 means metastasis has occurred.

Once the values for T, N, and M are determined, doctors assign NSCLC a stage grouping. The general stages of NSCLC are denoted using Roman numerals I to IV. Higher-stage lung cancers are often more severe and generally require more intense treatment.

Sometimes stages are subdivided using capital letters and additional numbers. For instance, stage IA1 or stage IIB. This subdivision allows doctors to provide more precise and detailed descriptions. Additionally, some lung cancers are classified as stage 0 (carcinoma in situ). This means that precancerous cells have been detected but have yet to spread.

The five general stages of NSCLC are:

• Stage 0 indicates precancerous cells that have not spread into the deeper lung tissue.
• Stage I lung cancer is limited to the lungs and has not spread to the lymph nodes.
• Stage II lung cancer may have spread to the nearby lymph nodes.
• Stage III lung cancer has spread to the lymph nodes and other nearby tissues.
• Stage IV lung cancer has spread from the lungs to other parts of the body.

Some doctors use the TNM system to classify SCLC. Typically, however, this type of lung cancer is considered either limited stage or extensive stage. In limited stage SCLC, the lung cancer is usually confined to one lung and the adjacent mediastinum. Radiation therapy in concert with chemotherapy is the preferred treatment for most limited stage patients.

Extensive stage SCLC describes cancers that have spread widely throughout the lung, to the other lung or chest tissues, or throughout the body. About two-thirds of patients¹ have extensive stage SCLC when they are diagnosed. The standard care for patients is primarily chemotherapy and immunotherapy with the discussion of radiation therapy following chemotherapy.

There are several ongoing clinical trials for patients with limited or extensive stage small cell lung cancer. If you are interested in enrolling in a clinical trial, ask your doctor if you may be a candidate.

Lung cancer staging is critical because it helps doctors determine an appropriate cancer treatment plan. But staging also provides insight into survival rates. Survival rates tell you the percentage of people with a certain type and stage of cancer who survived for a specific period of time, generally given by projections for two or five years.

Since these percentages are based on samplings of patients, they are considered averages. That means they may not exactly predict the outcome for a single individual, but they do provide patients with a better understanding of how effective their treatment may be.

Typical estimates for five-year survival rates2 for patients with NSCLC who undergo treatment are:

• Stage I, 54 percent
• Stage II, 35 percent
• Stage IIIA, 10 to 15 percent
• Stage IIIB, less than five percent
• Stage IV, less than two percent

Patients with stage 0 cancer should have an excellent five-year survival rate.

SCLC is an aggressive form of lung cancer that is more common in current and former smokers. Since SCLC spreads quickly, invading the blood and lymph nodes, survival rates are comparatively lower.

The general 5-year survival rate for people with SCLC is 7%. It is important to note that survival rates depend on several factors, including the stage of the disease.

For people with localized SCLC, which means the cancer has not spread outside of the lung, the overall 5-year survival rate is approximately 27%.

For regional SCLC, which means the cancer has spread outside of the lung to nearby areas, the 5-year survival rate is approximately 16%.

If the cancer has spread to a distant part of the body, the 5-year survival rate is 3%. However, some people with advanced lung cancer can live many years after diagnosis.

At SERO, we understand that an accurate lung cancer diagnosis can affect your treatment decisions, possible toxicities, and ultimate outcome. That is why our board-certified radiation oncologists use the most advanced diagnostic imaging tools available. This technology allows them to offer an accurate diagnosis and, in doing so, develop an effective cancer treatment plan.

To learn more about your lung cancer treatment options, contact us to schedule an appointment at one of our cancer treatment centers. We offer state-of-the-art radiation oncology services at over a dozen of locations in the Charlotte area

1. https://www.cancer.org/cancer/lung-cancer/detection-diagnosis-staging/staging-sclc.html
2. https://training.seer.cancer.gov/lung/intro/survival.html 
3. https://www.verywellhealth.com/lung-cancer-survival-rates-by-type-and-stage-2249401