What Is Stage 3 Non-Small Cell Lung Cancer?

Symptoms, Treatment, and Prognosis

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Non-small cell lung cancer (NSCLC) staging is based on a traditional four-stage model, with stage 3 indicating that the malignancy has spread to nearby (regional) tissues. Stage 3 is further broken down into stage 3A, when the disease is said to be locally advanced, and stage 3B, when the disease is considered advanced.

Around 35% of people with lung cancer have stage 3 disease at the time of diagnosis. Lung cancer staging is a very important step in choosing the best treatments, the option of which can differ significantly between stage 3A and stage 3B.

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An Overview of Staging For Non-Small Cell Lung Cancer

Staging

Stage 3 lung cancer is generally defined by the regional spread of cancer from the primary (original) tumor, with stage 3A and stage 3B differing in terms of the extent and location of the cancer spread.

Stage 3A vs. Stage 3B Lung Cancer

  • Stage 3A lung cancer includes tumors that are large and have spread to nearby lymph nodes, or tumors of any size that have spread to lymph nodes that are further away but still on the same side of the body as the cancer.
  • Stage 3B lung cancer is defined as a tumor of any size that has spread to distant lymph nodes or has invaded other structures in the chest (such as the heart or esophagus).

Note: Tumors involving a malignant pleural effusion (fluid build-up containing cancer cells in the pleural cavity between the layers lining the lungs) were changed from stage 3B to stage 4 in 2009.

Oncologists use a classification system called the TNM system to further characterize the stages of lung cancer. T refers to tumor size, N refers to lymph node involvement, and M represents spread (metastasis).

The most current version of this system, called TNM 8, describes the stage of cancer using alphanumeric codes to give each of these categories nuance.

Stage 3A lung cancer is described as:

  • T1N2M0: The tumor is less than 3 centimeters (cm) in size and has spread to lymph nodes farther away but on the same side of the body as the tumor.
  • T2N2M0: The tumor is larger than 3 cm but less than 5 cm and has spread to lymph nodes farther away but on the same side of the body.
  • T3N1M0: The tumor is larger than 5 cm or has spread locally to an area like the chest wall or pericardium; nearby lymph nodes are affected.
  • T3N2M0: The tumor is any size but is near an airway or has spread locally to an area like the chest wall or diaphragm; lymph nodes that are further away but on the same side of the body are affected.
  • T4N0M0: The tumor is larger than 7 cm or has spread locally to an area like the mediastinum or the diaphragm, but no lymph nodes are affected.
  • T4N1M0: The tumor is larger than 7 cm or has spread locally to an area like the mediastinum or the diaphragm; lymph nodes that are farther away but on the same side of the body are affected.

Stage 3B is described as:

  • Any T, N3, M0: A tumor of any size that has spread to lymph nodes on the other side of the chest from the tumor or to nodes near the collarbone or neck muscles; distant regions of the body are not affected
  • T3 or T4N2M0: The tumor has spread to nodes further away but on the same side of the chest (N2 nodes) and it is either large (>5 cm) or has invaded local structures.

Stage 3 Lung Cancer Symptoms

Stage 3 lung cancer symptoms are variable since stage 3 includes a wide spectrum of cancers. Lung cancer symptoms such as a persistent coughshortness of breath, and repeated infections such as pneumonia or bronchitis are common.

Cancer that has spread to areas such as the chest wall and diaphragm can result in pain in the chest, ribs, shoulders, and back.

Tumors located near the airways can cause hemoptysis (coughing up blood) and wheezing.

When the tumor involves areas such as the esophagus and other chest structures, dysphagia (difficulty swallowing) and hoarseness can occur.

Pain in the back, chest, and ribs is common if a pleural effusion is present, and this can result in increasing shortness of breath.

General symptoms of cancer such as fatigue and unintentional weight loss may be present as well.

Treatment

The treatment of stage 3 lung cancer is the most controversial of all lung cancer stages, partly because this group of malignancies is so varied.

Stage 3 lung cancers have a poor survival rate. Because of that, the National Cancer Institute (NCI) states that everyone with stage 3 lung cancer be considered a candidate for clinical trials (studies that evaluate new treatments or combinations of treatments for lung cancer).

Stage 3A Treatment

For some stage 3A lung cancers, surgery can be performed to remove the tumor and is usually followed up with adjuvant chemotherapy (chemotherapy after surgery). 

Surgery offers a chance for a cure but is not always possible with tumors of this size. The risk of cancer recurrence is also fairly high for people with stage 3A lung cancer.

For people that are relatively healthy, a combination of chemotherapy or chemotherapy and radiation therapy is often recommended. If individuals are unable to tolerate chemotherapy, radiation therapy can be used alone to treat symptoms such as pain and shortness of breath.

It's now recommended that molecular profiling (gene testing) be done for everyone with NSCLC especially lung adenocarcinoma. Medications have been approved for people with treatable mutations such as EGFR mutations, ALK rearrangements, and ROS1 rearrangements. Such drugs, known as targeted therapies, can sometimes result in excellent control of the disease.

Resistance often develops over time, but next-generation medications are currently approved and being tested in clinical trials for when this occurs. For those with squamous cell carcinoma of the lungs, anti-EGFR antibodies may be used. Clinical trials are also studying medications that address other genetic changes in lung cancer.

Five immunotherapy drugs have been approved for the treatment of lung cancer. These medications work by enhancing the ability of the body's own immune system to fight cancer. While the drugs do not work for everyone, some people have achieved long-term, disease-free control of their cancer.

Imfinzi (durvalumab), approved by the U.S. Food and Drug Administration (FDA) in February 2018, is an immunotherapeutic drug used for the treatment of inoperable stage 3 lung cancer after chemotherapy and radiation therapy have failed to control progression. When used in this setting, it was found to significantly improve progression-free survival.

Stage 3B Treatment

Stage 3B cancers, unlike stage 3A, cannot usually be treated with surgery. But while they are inoperable, they are treatable. Treatments may include chemotherapy, radiation therapy, targeted therapies, and immunotherapy (as with stage 3A disease).

In some cases, the use of chemotherapy and radiation therapy is able to decrease the size of a tumor so that surgery is then possible. Chemotherapy used in this way is referred to as neoadjuvant chemotherapy.

For people with stage 3 lung cancer, treatments can also be used for palliative purposes. In this case, the focus of treatment is relieving symptoms such as pain and shortness of breath, rather than trying to control the malignancy.

In some cases, palliative therapy might actually improve survival for people with stage 3 lung cancer.

Prognosis

The overall five-year survival rate for stage 3A lung cancer is 10% to 15%, but it can vary widely. The five-year survival rate with stage 3B lung cancer is less promising at less than 5%. 

It's important, however, to keep in mind that these statistics are based on how people did with lung cancer in the past. Since there have been more medications approved for the treatment of lung cancer in the last decade than during the four decades preceding it, these statistics are fairly unreliable in estimating actual life expectancy.

Prognosis is a prediction. An estimate. An open conversation with your doctor about your specific case and what prognosis can and cannot tell you can be helpful in putting this in perspective.

Coping

Studies suggest that learning what you can about your cancer helps with the outcome. Ask questions. Involve your loved ones and encourage them to ask questions as well. Consider joining a support group. Learn about clinical trials that might be appropriate for your particular situation.

Learning about your cancer and going through treatment can take a tremendous amount of time. Ask for and allow your loved ones and friends to help and encourage you in your journey. Don’t lose hope—even if that hope is only to be as comfortable as possible while you enjoy the company of your loved ones.

A Word From Verywell

As frightening as stage 3 lung cancer can be, the screening of high-risk individuals may be able to catch the disease in earlier, more treatable stages. This involves an annual low-dose computed tomography (CT) chest scan for people ages 55 to 80 who have a 30 pack-year smoking history and currently smoke or have quit smoking within the past 15 years.

According to the American Lung Institute, eight million Americans are considered at high risk of lung cancer. If only half of these individuals were screened, over 12,000 lung cancer deaths could be avoided.

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