What Is Stage 3 Cancer?

In stage 3 cancer, the tumor is larger or has spread (metastasized) farther than in earlier stages. Some stage 3 cancers are divided into three subcategories: 3A, 3B, and 3C. These categories are usually determined by the size and number of tumors and how far the cancer has spread.

There are effective treatments for many stage 3 cancers. Some stage 3 cancers can be successfully treated, but they are more likely to return after going away. 

This article reviews how stage 3 cancer is diagnosed. It also explains what this means for a person’s treatment and prognosis.

What Is Stage 3 Cancer?

Staging affects treatment options, survival rates, and the potential for remission. Remission is a period with no signs or symptoms of cancer; however, cancer may still be present in the body.

Healthcare providers use a system developed by the American Joint Committee on Cancer (AJCC) to assess the cancer stage. This three-part system is called the TNM system. The letters and numbers differ from cancer to cancer, but they have the same structure:

• T defines the tumor itself. Healthcare providers analyze its size and how far it has spread into the surrounding tissues and organs. The T rating ranges from 0 to 4. The bigger the tumor and the more it has spread, the worse the prognosis is likely to be.
• N describes the extent of lymph node involvement and the number of lymph nodes in the area of the tumor. Lymph nodes are glands in your immune system. A tumor’s N value varies from 0 to 3 depending on how far it has spread.
• M stands for metastasis. That's the spread of cancer cells to other organs. There are only two M Stages: 0 for no and 1 for yes. It is harder to treat cancer that has spread.
  

On the TNM scale, stage 3 cancer is considered relatively advanced, with stage 4 being the highest. The tumor has usually grown large, and diseased tissue can be found in other nearby organs. It is also called locally advanced cancer or regional cancer.

Stage 3 Diagnostic Criteria

We tend to talk about all stage 3 cancers as if they are the same. In reality, these diagnoses differ widely based on cancer type. A stage 3 cancer often has one or more of three features:

• The tumor has grown beyond a certain size, usually measured in centimeters (cm).
• It has spread to a set of nearby lymph nodes (such as the axillary lymph nodes in breast cancer).
• It extends into nearby structures (for example, the chest wall in breast cancer).
  

Some stage 3 cancers are subdivided to classify them more precisely. These sub-stages differ based on which organ is involved. For example, stage 3 breast cancer has three subcategories:

3A:

• The tumor is smaller than 5 cm and has spread to between four to nine underarm lymph nodes or the nodes near the breastbone. 
• The tumor is larger than 5 cm and has spread to one to three underarm lymph nodes.

3B:

• The tumor is any size.
• The tumor has invaded the chest wall or the breast is swollen, inflamed, or has ulcers (diagnosed as inflammatory breast cancer).
• It may have also invaded up to nine underarm lymph nodes or those near the breastbone.

3C:

• The tumor is any size.
• It has spread to 10 or more lymph nodes in the underarm, collar bones, or the breastbone.

Other Factors

There are a few other things that help healthcare providers determine a cancer’s stage:

• Cell type: Even when cancers occur in the same organ, they might act differently based on what kind of cell turned cancerous. Each of our organs has many types of cells, any of which could become cancerous. The cell type can affect how cancer acts and reacts to treatments. For example, esophageal cancer from the mucus-producing gland cells reacts to treatment differently from cancer in the lining of the esophagus.
• Tumor location: Where in an organ the tumor is found can affect the cancer's stage. For example, esophageal cancer staging partly depends on what part of the esophagus has cancer.
• Tumor blood markers: For certain cancers, healthcare providers can test the blood for certain cellular materials. Usually, it's proteins. These markers can help them decide on a stage. For example, prostate cancer stage depends on blood levels of a protein called prostate-specific antigen (PSA). Higher levels of PSA could mean a more advanced stage of cancer.
• Tumor genetics: A tumor's genes and mutations influence cancer’s staging. When the body’s cells turn cancerous, their genes change rapidly and develop new traits.
  

Cancer Staging Tests and Procedures

Because cancers are so complicated, many tests and procedures are used to stage them. They vary by the type of tumor. Not all tests are appropriate for all cancers.

Imaging Tests

Imaging tests like X-ray, computed tomography (CT), magnetic resonance imaging (MRI), ultrasound, and positron emission tomography (PET) scans let healthcare providers see inside the body without cutting it open. These images give them a better idea of the size and makeup of a tumor. They can also provide information about other affected organs and blood flow.

Endoscopy

Endoscopy involves a surgeon inserting a small tube or wire into the body to look at the organs with a small camera. It includes tests like:

• Colonoscopy to screen for cancers in the lower digestive tract
• Bronchoscopy to visualize the bronchi that reach the lungs
• Laparoscopy to view the abdomen or pelvis

The surgeon uses the scope to take pictures or tissue samples of unusual areas. 

Biopsy

During a biopsy, a healthcare provider takes a tissue sample of the tumor, then looks at it under a microscope. These tissue samples can be from anywhere on the body, including the skin, bone marrow, or breast. Some biopsies use a vacuum device to draw out tissue samples through a needle. This process is called fine-needle aspiration (FNA).

Lab Tests

Healthcare providers can learn a lot by testing your blood, other body fluids, and tissue samples. Tests can look for tumor markers that tell them more about your cancer. They can test the cancer’s genes to learn more about it. They can also do general blood testing to keep track of your health.

How Stage 3 Cancer Is Treated

Treatment for stage 3 cancers varies according to which organ is affected. The more advanced the stage is, the more challenging it is to treat.  

Surgery is often the first line of defense against a tumor. Some surgeries involve an open incision. Others use a tiny incision and a camera on a flexible tube. The goal is to remove the cancerous tissue.

In some cases, stage 3C cancers will need other treatments to shrink the size of the tumor. Here's how some of those treatments work:

• Chemotherapy uses potent drugs to kill cancer cells. It can also help ease symptoms from stage 3 cancer. Chemo kills the body’s fast-growing cells, such as those that line the mouth or hair follicles. That causes many side effects, including hair loss.
• Radiation therapy uses radiation to kill cancer cells. Radiation is energy that can damage cells, so it is used to weaken the cancer cells. This treatment is usually targeted to the area of the body where the cancer is. It can take days or weeks to see an impact.
• Hormone therapy is also known as endocrine therapy. It's used with tumors that need hormones to grow. Prostate and breast cancers are two examples. By depriving the cancer cells of hormones, the treatment keeps cancer from growing as quickly. It also eases cancer symptoms. Because these treatments target the body’s hormones, they have side effects that differ by sex.
• Targeted therapy is a form of personalized medicine. It attacks the cancer based on its genetics. These therapies can slow or stop the growth of cancer cells by targeting the gene changes that let these cells grow out of control. Targeted therapies can be drugs or antibodies made against the tumor’s special proteins.
• Immunotherapy uses the body’s immune system against cancer. It might be surprising, but the body has ways to find and destroy cells that could become cancer. These therapies help support the body’s immune system as it fights cancer.

Treatments for Common Cancers

Which treatments the oncologist (cancer specialist) uses will depend on the type of cancer, how far it has spread, and many other factors. Here are three treatment approaches as examples:

• Breast cancer: Stage 3 breast cancers are often treated with chemotherapy to shrink the tumor’s size before surgery. After surgery, radiation and hormone therapies may be used to kill any cancer cells that are left.
• Colorectal cancer: The first move for stage 3 colorectal cancer is often surgery to remove cancer from the colon and lymph nodes. Radiation may be used on the parts of the tumor they couldn’t completely remove.
• Melanoma: Treatment for stage 3 melanoma starts with surgery to remove a wide area of skin and the lymph nodes. Immune and targeted therapies can reduce the risk of the tumors coming back. Radiation or chemotherapy may follow if the lymph nodes are heavily involved.

When the signs and symptoms of cancer have gone away, healthcare providers say the treatment was successful and the patient is in remission. Remission rates for stage 3 cancers vary by the type of cancer and available treatments. 

Treatment plans for stage 3 cancer can be complex. They often involve many healthcare providers and facilities. One thing that can help patients is a palliative care team. These health and social work teams work to relieve symptoms, treat side effects, and improve patients’ stress levels. No matter what stage of cancer, palliative care can help.

What Is the Prognosis For Stage 3 Cancer?

The prognosis or outlook for stage 3 cancer depends on many factors. Some examples are:

• Cancer type
• Grade
• Genetics
• Traits such as age, health, and smoking history

Another factor is known as performance status. It's a way of scoring your ability to perform everyday tasks.

Healthcare providers use survival rates to estimate how likely it is that someone with a certain diagnosis will still be alive in five years. The cancer-specific survival rate would be the portion of people with a particular diagnosis who had not died from that cancer. The relative survival rate estimates how many of those people had not died from anything (cancer or otherwise) during that time.

Survival Rates and Cancer

Survival is typically measured in five-year rates (the number of people in 100 who are expected to live for at least five years). You might see one-year, two-year, and 10-year survival rates, too.

You can find cancer survival rates in the National Cancer Institute’s Surveillance, Epidemiology, and End Results (SEER) Program’s database. It has been reporting cancer statistics from 19 states since 1973.

The SEER database does not use the TNM staging system. Cancer registries like SEER typically use a three-stage approach:

• Localized: the cancer cells are only in the area in which it first grew
• Regional: the cancer has spread to nearby lymph nodes, tissues, or organs (generally, this includes Stage 3 cancers)
• Distant: the cancer has spread to remote parts of the body

The figures below are from the NCI’s SEER database. It tracks how many cases of cancer are diagnosed and what the outcomes are. The numbers below are the five-year survival rates for the top 10 cancers at a "regional" stage. This data was collected from 2013 to 2019.

*Note that healthcare providers stage lymphoma and leukemia differently. The non-Hodgkin lymphoma number is the stage 3 survival. The leukemia number is the overall five-year relative survival rate for any stage. 

Questions to Ask Your Healthcare Provider

It's important that you understand your diagnosis and treatment, and your oncology team can help with questions you have about your care and its outcomes. Some things you may want to know include:

• How will the cancer be diagnosed?
• What do the results of the diagnostic tests and procedures mean?
• What treatment options exist and how will a treatment plan be determined?
• How long will the treatment last, and what kinds of side effects will you experience?
• How will the treatment affect your work and family life?

Don't hesitate to ask about emerging treatments, such as targeted therapies, or clinical trials in which new treatments are tested.

Your healthcare team can also help you to connect with support groups and other resources. Online and in-person support groups are available for nearly any cancer. You can share experiences and ask questions with people who have lived with breast, lung, or other types of cancer.

Summary

Stage 3 cancer is fairly advanced. It often means that a tumor has grown larger and cancer cells can be found in lymph nodes and other nearby organs. To discover exactly how far cancer has spread, healthcare providers use a variety of tests.

Public health organizations keep track of new cancer cases and deaths from cancer. They estimate the chances that someone with a certain type and stage of cancer will be alive in one, two, five, or 10 years' time. The outlook for a person with stage 3 cancer depends on more than this estimate, though. Overall health, age, the type of cancer, its stage, and treatments all shape the prognosis.

A Word From Verywell

A cancer diagnosis is a life-changing event. This is especially true if you're diagnosed with later-stage cancer. But stage 3 cancer isn’t a death sentence. Survival rates are improving, and researchers are continually discovering and testing new targeted drugs and immunotherapies.