Colorectal cancer is cancer that develops in your large intestine (colon) or rectum. It’s the second most common type of cancer in women and the third most common in men.

Colorectal cancer can spread to other parts of your body through your bloodstream or lymphatic system. The liver is the most common place for colorectal cancer to spread.

Read on to learn why colorectal cancer spreads to the liver and how liver involvement affects treatment.

About 70% of people with colorectal cancer develop metastatic liver cancer. Metastatic liver cancer means that the cancer didn’t originate in the liver but spread from somewhere else, like the colon or rectum.

The reason that colorectal cancer often spreads to the liver is because of the direct blood vessel connection that exists between the large intestine and the liver through the portal vein. If the cells within the walls of the colon or rectum begin to mutate and become cancerous, it’s easy for these damaged cells to get transported directly to the liver through the bloodstream.

Even though the cancerous cells originated in the colon or rectum, they can still continue to grow and spread within the liver. If these malignant cells continue to grow, they can form tumors that begin to impact the liver and make it hard for the liver to function properly.

About 14% to 18% of people with colorectal cancer have metastasized cancer at their first medical consultation. However, this number is closer to 35% when a computed tomography (CT) scan is used to detect whether the cancer has spread to the liver.

Research suggests that colorectal cancer may spread early during the disease and possibly years before the cancer is detected.

Colorectal cancer is divided into stages I to IV depending on how advanced the cancer is. It’s known as stage IV if the cancer has spread to the liver or another distant organ, such as the lungs or brain.

The primary test for diagnosing colorectal cancer is a colonoscopy with a biopsy. A biopsy is a small tissue sample of the colon lining that’s taken during a colonoscopy. The tissue sample is then sent for lab analysis to determine if it contains cancer cells. A biopsy is needed to make a definitive cancer diagnosis.

Imaging tests are used to diagnose whether the cancer has spread to the liver or another distant organ. The types of imaging tests used may include:

When you have colorectal cancer that’s spread to your liver, you may be able to have surgery to remove the cancer from both your colon and your liver. Chemotherapy is also a common treatment for colorectal cancer.


Surgery to remove cancer from the colon may include:

  • hemocolectomy, which involves removing part of the colon that contains the cancer and a small section of normal colon on either side and then reattaching the colon; lymph nodes are also removed to check for cancer cells
  • total colectomy, which is a less common procedure that involves removing the entire colon

You may need chemotherapy before surgery to shrink the cancer in your colon and/or liver. Chemotherapy is often administered after surgery to destroy any remaining cancer cells. This is known as neoadjuvant chemotherapy.

Surgery to remove cancer in your liver is usually only possible if the cancer is contained in a small portion of your liver. Surgery is only an option in about 20% to 30% of people with metastatic colon cancer. According to research, 39% to 58% of people who have liver surgery live for at least 5 years after the procedure.

Your surgeon will remove as much of the cancer as possible from your colon and your liver. These surgeries may be done at the same time, or at different times. Your doctor will let you know which option is best for you.

Ablation and embolization

Small tumors may be removable with ablation or embolization instead of surgery.

Ablation is used to destroy tumors less than 4 centimeters (cm) (1.6 inches) across in size. Ablation techniques that are used for cancer cells in the liver include:

  • radiofrequency ablation is the most common ablation method that uses high-energy radio waves to heat and destroy cancer cells
  • ethanol ablation involves a concentrated injection of alcohol into tumors to kill off cancer cells
  • microwave ablation uses electromagnetic waves to heat and destroy cancer
  • cryosurgery involves the use of cold gasses to freeze and destroy cancer cells

Embolization is a procedure where a substance is injected into an artery that supplies your liver. The aim of this procedure is to cut off the blood supply to the cancerous cells in the liver.

Embolization may be an option for people who have tumors that are larger than 5 cm across, that cannot be treated with surgery or ablation, and who still have adequate liver function.


Chemotherapy (chemo) is commonly used to treat colorectal cancer at all stages. It may be used in the following ways:

  • As neoadjuvant chemotherapy: Chemo may be necessary before surgery to help shrink cancerous tumors. Sometimes this is done in combination with radiation. Chemo treatment at this point in time helps make the cancer easier to remove during surgery. Neoadjuvant chemo is usually given for a total of 3 to 6 months, depending on what types of chemo drugs are used.
  • As adjuvant chemotherapy: In this instance, chemo drugs are given after surgery. The goal with adjuvant chemo is to destroy any cancer cells that may have been left behind after the cancer was surgically removed, or to target any cancer cells that are too small to be detected with imaging tests. Like neoadjuvant chemo, this treatment usually also lasts for 3 to 6 months.
  • For advanced cancers: Chemo drugs can help shrink tumors that have spread to distant organs like the liver, lungs, brain, and other areas. Although it won’t cure colorectal cancer, it can help ease symptoms that may be causing discomfort, and can help prolong a person’s life.

Many chemotherapy options are available. According to the American Cancer Society, some of the most common chemo treatment combinations include:

  • FOLFOX: folinic acid, fluorouracil, and oxaliplatin
  • FOLFIRI: leucovorin, fluorouracil, and irinotecan
  • CAPEOX: capecitabine and oxaliplatin
  • FOLFOXIRI: leucovorin, fluorouracil, oxaliplatin, and irinotecan

Other treatments

As scientists continue to learn more about the changes that occur in cells that allow colorectal cancer to develop, new types of targeted drugs are being developed that can focus on those cell mutations.

Unlike chemo drugs, which destroy both cancerous cells and healthy cells, targeted therapy drugs only go after cancer cells. These targeted therapies can be used together with chemotherapy or on their own.

Another treatment area that’s expanding for colorectal cancer, including cancer that has spread to the liver or elsewhere, is immunotherapy. This involves the use of medicines to help your own immune system detect and destroy cancer cells.

The 5-year relative survival rate for colon cancer in the United States is 64%, while the relative survival rate for rectal cancer is 67%. When cancer reaches distant organs, the 5-year survival rate drops to 14% for colon cancer and 17% for rectal cancer.

The 5-year relative survival is a measure of how many people with a disease are alive 5 years later compared to people without the disease.

Resources for colorectal cancer

Dealing with a colorectal cancer diagnosis can be challenging. Here are some resources you might find helpful if you or a loved one is looking for support.

Colorectal cancer can spread to other parts of your body through your blood or lymph system. The most common organ that colorectal cancer spreads to is the liver due to the rich blood supply that exists between the large intestine and the liver.

Treatment for colorectal cancer that has spread to the liver often involves a combination of surgery, chemotherapy, and targeted therapy. Many different types of chemo drugs can be used for colorectal cancer. Your oncologist will work closely with you to determine which combination of treatments is best for you.