Stage 4 colon cancer is cancer that starts in the colon and spreads to other parts of the body. Stage 4 colon cancer also is known as metastatic, late-stage or distant colon cancer.

Up to half of the people diagnosed with colon cancer eventually develop cancer in other parts of the body. These are known as metastases. The liver, lungs, abdominal cavity or distant lymph nodes are the most common locations for colon cancer to metastasize.

Stage 4 colon cancer typically requires complex treatment strategies to manage symptoms and improve quality of life. Treatment for stage 4 colon cancer may include chemotherapy, surgery, targeted therapy, immunotherapy or radiation.

When to see a doctor

Make an appointment with a doctor or other healthcare professional if you have any symptoms that worry you. If you've been treated for colon cancer in the past, tell your healthcare professional.

It's not clear what causes colon cancer to metastasize and progress to stage 4. This advanced form of colon cancer happens when cancer cells break away from where they started in the colon. The cancer cells can travel through the lymphatic system or the bloodstream to other areas of the body. Colon cancer cells also may spread by growing into nearby tissue or traveling to the lining of the abdominal cavity, called the peritoneum.

Cancer that spreads from its original location is known by the name of the primary cancer. For example, cancer that has spread from the colon to the liver is called metastatic colon cancer, not liver cancer.

Colon cancer most often spreads to the:

• Liver.
• Lungs.
• Abdominal cavity lining, called the peritoneum.
• Distant lymph nodes.

Less commonly, colon cancer spreads to the:

• Bones.
• Brain.
• Ovaries.

Factors that raise the risk of metastatic colon cancer are the same for colon cancer in general. These include being older than age 45, lifestyle factors, genetic traits and certain conditions, such as inflammatory bowel disease, Lynch syndrome or familial adenomatous polyposis.

While these factors increase the likelihood of colon cancer, they don't guarantee it will progress to metastatic disease. Additional factors that increase the risk of advancement to stage 4 include:

• Late diagnosis. When colon cancer isn't caught early, it can grow and spread to other parts of the body. This often happens because younger people may have unusual symptoms that don't seem serious, or their symptoms are mistaken for harmless issues like stomach upset or hemorrhoids.
• Lack of screening. If people don't get screened regularly or at all, healthcare professionals might miss growths in the colon that could turn into cancer or cancer could be caught too late. This makes it more likely for cancer to progress.
• Aggressive types of cancer. Some types of colon cancer, such as those with specific genetic changes, grow quickly and are more likely to spread to other parts of the body.

While these factors increase the risk of stage 4 colon cancer, it's possible to slow down progression. Early intervention can improve outcomes.

Stage 4 colon cancer, also known as metastatic colon cancer, is linked to a range of serious complications. This is due to both the primary cancer that started in the colon and the spread of cancer to distant organs. Complications may include:

• Bowel obstruction. Cancer may grow large enough to block the colon. This can cause belly pain, bloating and nausea.
• A tear in the colon, called a perforation. A perforation is a dangerous complication that can lead to contamination and infection in the abdominal cavity. It often needs emergency surgery.
• Bleeding. Cancer may cause either slow, ongoing bleeding that leads to anemia or, less commonly, life-threatening hemorrhage.
• Liver dysfunction or failure. The liver is the most common site for colon cancer spread. Cancer in the liver can lead to liver dysfunction or failure. Signs of liver problems include belly swelling, confusion, and yellowing of the skin and eyes, called jaundice.
• Lung complications. Cancer that spreads to the lungs can cause coughing, shortness of breath or fluid around the lungs, called pleural effusion.

Metastatic colon cancer is diagnosed through a combination of imaging tests, lab tests, genetic testing and tissue samples, called biopsies. Common diagnostic procedures include:

Biopsy

A biopsy is a procedure to remove a sample of tissue for testing in a lab. For colon cancer, the tissue sample often is collected during a colonoscopy. Sometimes surgery is needed to get the tissue sample. In the lab, tests can show whether the cells are cancerous and what type of cancer it is. Other tests performed on the cancer cells can give information about the gene changes present in these cells, shed light on the aggressiveness and guide treatment strategies. Your healthcare team uses all of this information to understand your prognosis and create a treatment plan.

Imaging tests

Imaging tests can look for areas of cancer inside the body. CT and MRI scanning are the main imaging tests used to detect colon cancer and assess how far the cancer has spread when you've already been diagnosed with colon cancer.

A PET scan also may be helpful to decide if surgery is an option for cancer that has spread outside the colon.

Molecular and genetic testing

Some colon cancers have gene changes that affect how the cancer grows and how well it responds to treatment. These genetic features are found by testing the cancer in a lab. These tests help doctors choose the best treatment for you. Some medicines only work for certain gene changes.

Carcinoembryonic antigen (CEA) testing

Carcinoembryonic antigen, also called CEA, is a protein made by some colon cancer cells. It can be measured with a simple blood test. High levels of CEA can indicate the presence or progression of colon cancer, especially in advanced or metastatic stages. CEA may be used to track how well treatment is working or monitor for colon cancer coming back. It is important to note that CEA can be elevated in patients with noncancerous conditions.

Stage 4 colon cancer, also called metastatic colon cancer, means the cancer has spread to other parts of the body — often the liver, lungs or abdominal cavity lining, called the peritoneum. While surgery may offer a cure for some people, this stage of cancer is not usually curable. However, many treatments can help people live longer and feel better. Depending on your situation, you may be eligible to take part in a clinical trial. Ask your healthcare team if there are available options for your type of cancer.

Many people with metastatic colon cancer will receive a mix of treatments over time — chemotherapy, surgery, targeted therapy, immunotherapy or radiation. Your care team will adjust your plan based on how your cancer responds and how you feel.

Chemotherapy

Chemotherapy uses strong medicines to kill colon cancer cells or slow their growth. It's usually the first treatment given after diagnosis of metastatic colon cancer. Chemotherapy for metastatic colon cancer may be given in the following situations:

• After colon cancer surgery. Chemotherapy usually is given after surgery if the cancer is large or has spread to the lymph nodes. Chemotherapy can kill cancer cells that might be left after surgery. This helps reduce the risk of the cancer coming back. Chemotherapy given after surgery is called adjuvant chemotherapy.
• Before colon cancer surgery. Chemotherapy might be used before surgery to shrink a large cancer so that it's easier to remove. Chemotherapy given before surgery is called neoadjuvant chemotherapy.
• Symptom relief. Chemotherapy can be used to relieve symptoms and slow down the growth of colon cancer that can't be removed with surgery or that has spread to other areas of the body. It can help reduce pain, bleeding or blockages, extend life, and improve quality of life. This type of chemotherapy is sometimes called palliative chemotherapy. Sometimes it's used with radiation therapy.

Chemotherapy is usually delivered through an intravenous line (IV) or sometimes as a pill. Treatment is given in cycles, with periods of treatment followed by rest. Most treatments are given every 2 to 3 weeks, depending on the medicines used.

A common first line chemotherapy treatment combination includes 5-fluorouracil (5-FU), leucovorin and oxaliplatin, known as FOLFOX. Another first line treatment option is 5-fluorouracil (5-FU), leucovorin and irinotecan, known as FOLFIRI.

There are other chemotherapy combinations available for metastatic colon cancer. Your care team will choose one based on your overall health and test results.

Focused chemotherapy for metastatic colon cancer

These specialized chemotherapy treatments may be used to treat colon cancer that has spread specifically to the liver or abdominal cavity, called the peritoneum:

• Hepatic artery infusion pump (HAIP) chemotherapy targets colon cancer that has spread to the liver. The process starts with the surgical implantation of a small pump under the skin, typically in the belly. This pump delivers chemotherapy directly to the liver through the liver's main artery, called the hepatic artery. HAIP chemotherapy is generally combined with traditional, systemic chemotherapy.
• Cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC) is a combination cancer treatment. It's used for colon cancer that has spread to the peritoneum. In this treatment, all the cancer is first surgically removed from the peritoneum. Then the abdominal cavity is bathed with hot chemotherapy to kill any microscopic cancer cells that remain.
• Pressurized intraperitoneal aerosol chemotherapy (PIPAC) is a newer way to treat cancer that has spread to the peritoneum. During PIPAC, a special mist of chemotherapy medicine is delivered directly into the belly during a minimally invasive procedure. The medicine is delivered as a fine aerosol under pressure, which helps it spread evenly throughout the belly. PIPAC is typically done when surgery isn't possible or when surgery would be too risky or would not be helpful.

Surgery

Colon cancer most often spreads to the liver or lung. But it can spread to other places, including the peritoneum, distant lymph nodes or the brain.

For metastatic colon cancer, surgery may be used to:

• Remove primary colon cancer. If cancer is causing symptoms such as bleeding, blockage or a hole in the colon, surgery may be recommended to remove it. However, if the tumor isn't causing symptoms and the cancer has already spread, surgery may not be needed right away.
• Remove cancer that has spread. If cancer has only spread to the liver, and doctors think all tumors can be removed safely, surgery may offer the chance for long-term survival — and even a potential cure. In select cases, removing cancer that has spread to the lungs also can lead to longer survival, especially if the cancer is not widespread.

Chemotherapy might be used before or after surgery. Using a combination of surgery and chemotherapy may provide a chance to be free of cancer over the long term.

If cancer has spread to multiple organs or cannot be fully removed, surgery is usually not helpful as the main treatment. Instead, recommendations typically focus on chemotherapy and other systemic treatments to control cancer and improve symptoms.

Targeted therapy

Targeted therapy plays an important role in treating metastatic colon cancer, especially when standard chemotherapy alone is not enough. Doctors choose these medicines based on special tests of the cancer genes. Targeted therapy usually is combined with chemotherapy.

These treatments work by blocking specific genes, proteins or pathways that help cancer grow and spread, including:

• Vascular endothelial growth factor (VEGF). VEGF helps tumors grow new blood vessels. Bevacizumab (Avastin) is the most common anti-VEGF medicine.
• Epidermal growth factor receptor (EGFR). EGFR promotes cancer growth. Cetuximab (Erbitux) and panitumumab (Vectibix) target EGFR. These medicines are used to treat people with genetic changes known as RAS wild-type gene.
• BRAF, KRAS, NRAS, HER2 and others. These genes are linked to changes that may cause colon cancer. Recommended medicines depend on your specific genetic makeup. Some include encorafenib, trastuzumab, larotrectinib and entrectinib, among others. These medicines may be combined with other targeted therapy medicines.

Immunotherapy

Immunotherapy is a treatment with medicine that helps the body's immune system kill cancer cells. The immune system fights off diseases by attacking germs and other cells that shouldn't be in the body. Cancer cells survive by hiding from the immune system. Immunotherapy helps the immune system cells find and kill the cancer cells.

Immunotherapy usually is used only for people whose colon cancers have specific genetic features. Only about 3% to 6% of metastatic colon cancers have these features.

Radiation therapy

Radiation therapy uses powerful energy beams to kill cancer cells. The energy can come from X-rays, protons or other sources. When surgery isn't an option, standard radiation therapy might be used to relieve symptoms, such as pain. Some people have standard radiation and chemotherapy at the same time.

A different, highly specialized form of radiation called stereotactic body radiotherapy may be used to target small liver and lung cancers for some people. Called SBRT for short, this type of radiation delivers very high doses of radiation with great precision. SBRT may be done in addition to surgery or may provide an alternative if surgery isn't an option.

Intraoperative radiation therapy (IORT) is a radiation treatment that's done during surgery. IORT directs radiation to the target area while affecting the surrounding tissue as little as possible. IORT is used to treat cancers that are difficult to remove during surgery. And it's used when there's a concern that tiny amounts of unseen cancer might remain. IORT is often combined with standard radiation therapy.

Ablation

Ablation is a technique that can destroy cancer without surgery. It's usually done by inserting a probe into the cancerous tissue, guided by imaging such as a CT scan or ultrasound. The probe may use heat, cold or microwave to kill the cancer. Ablation may be used in addition to surgery, systemic chemotherapy or targeted therapy.

Liver transplant

Liver transplantation may be an option for people with metastatic colon cancer that cannot be surgically removed but has responded well to chemotherapy. While this approach shows promise, it is not yet considered standard care and is currently limited to clinical trials or treatment at highly specialized centers.

Palliative care

Palliative care is a special type of healthcare that focuses on relieving pain and other symptoms of a serious illness. Palliative care involves a team of healthcare professionals. The team can include doctors, nurses and other specially trained professionals. Their goal is to improve the quality of life for people with serious illnesses and their families.

Palliative care is an extra layer of support during cancer treatment. When palliative care is used with other cancer treatments, people with cancer may feel better and live longer.

It can be hard to cope with a cancer diagnosis. In time, people learn to cope in their own ways. Until you find what works for you, you might try to:

• Learn enough about your cancer to make treatment decisions. Ask your healthcare team about your treatment options and their side effects. The more you know, the more you'll be able to take part in decisions about your care. Ask your healthcare team to recommend other sources of information, such as websites you can trust.
• Keep friends and family close. Keeping people you care about close to you can help you deal with cancer. Friends and family can help you take care of things if you're in the hospital. And they can offer you support when you feel like you have too much to handle.

• Find someone to talk with. Find a good listener who will listen to you talk about your hopes and fears. This may be a friend or family member. Talking to a counselor, medical social worker, clergy member or cancer support group also might be helpful.

  Ask your healthcare team about support groups in your area. Or contact a cancer organization, such as the National Cancer Institute or the American Cancer Society.

If you have stage 4 colon cancer, you'll likely be sent to specialists who treat advanced disease. You might meet with:

• A doctor who uses medicines to treat cancer, called an oncologist.
• A doctor who removes colon cancer using surgery, called a surgeon or surgical oncologist.
• A doctor who uses radiation to treat cancer, called a radiation oncologist.

Here's some information to help you get ready for your appointment.

What you can do

Ask a family member or friend to go to your appointment with you. This person can help you remember the information you're told.

Make a list of:

• Your symptoms and when they began.
• Key medical information, including other conditions you have and your family medical history.
• All medicines, vitamins or supplements you take, including doses.
• Questions to ask your healthcare team.

Some basic questions to ask include:

• Where has the cancer spread in my body?
• What is the stage of my cancer?
• How serious is my condition?
• Can you explain the lab report of my cancer to me?
• Can I have a copy of my lab report?
• Will I need more tests?
• What are the treatment options for my colon cancer?
• What is the chance that my colon cancer can be cured?
• What are the potential side effects of each treatment?
• How will each treatment affect my daily life?
• How much time can I take to decide about treatment?
• Are clinical trials available for me?

What to expect from your doctor

Be prepared to answer some basic questions about your symptoms, such as:

• What are your symptoms?
• Is there a family history of colon cancer or other cancers, especially at a young age?
• Have you or any relatives been tested for Lynch syndrome or other hereditary cancer conditions?
• Do you have any other health conditions, such as diabetes, heart disease or kidney issues?