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 cured, 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 survival rates, treatment options, and the potential for remission. Remission is a period with few cancer symptoms.

Healthcare providers use a system developed by the American Joint Committee on Cancer 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 TMN scale, stage 3 cancer is considered advanced. The tumor has usually grown large, and diseased tissue can be found in other 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).
• 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 centimeters (cm) but has spread to 4-9 nodes. 
• The tumor is larger than 5cm and has spread to 1 to 9 nodes.

3B:

• The tumor is any size but has invaded the chest wall or breast skin.
• It is swollen, inflamed, or has ulcers.
• It may have also invaded up to nine nearby nodes.

3C:

• The tumor is any size.
• It has spread to 10 or more lymph nodes, nodes near the collar bones, or lymph nodes near the underarm and breast bone.

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. Here are a few of the standard tests and what they check for:

• Imaging tests: Imaging tests like X-ray, computed tomography (CT), 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 a colonoscopy, bronchoscopy, and laparoscopy. The surgeon uses the scope to take pictures or 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. Most are harder to treat than stage 1 or 2 cancers. 

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 ease cancer symptoms. 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.

Which treatments the oncologist uses depends 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 doctors, nurses, and centers. One thing that can help patients is a palliative care team. These doctors, nurses, and social workers work with seriously ill patients to relieve symptoms and treat side effects. They work to 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 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: In which the cancer cells are only in the area in which it first grew
• Regional: In which the tumor has spread to nearby lymph nodes, tissues, or organs (generally, this includes Stage 3 cancers)
• Distant: In which 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 2010 to 2016.

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. 

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 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.