Saint Luke’s Cancer Institute is committed to providing comprehensive care for patients with colorectal cancer, offering personalized care and treatment plans individualized for each patient’s specific needs.

What Is Colon and Rectal Cancer (Colorectal Cancer)?

What Is Colon and Rectal Cancer (Colorectal Cancer)?

Outline of adult abdomen showing arteries and lymph nodes of colon.Cancer happens when cells in the body begin changing and multiplying out of control. These cells can form lumps of tissue called tumors. Cancer that forms in the colon is called colon cancer. Cancer that forms in the rectum is called rectal cancer. These cancers are similar, so they are sometimes just called colorectal cancer.

Understanding the colon and rectum

The colon and rectum make up the large intestine (or large bowel), which is last part of the digestive tract. The colon is a muscular tube that forms the last part of the digestive tract. It absorbs water and stores food waste. The colon is about 5 feet long. The rectum is the last 6 inches of the large intestine. The colon and rectum have a smooth inner lining composed of millions of cells. Changes in these cells can lead to growths in the colon that can become cancerous and should be removed.

When the colon lining changes

Changes that happen in the cells that line the colon or rectum can lead to growths called polyps. Over a period of years, polyps can turn cancerous. Removing polyps early may prevent cancer from ever forming.

  • Polyps are fleshy clumps of tissue that form on the inner lining of the colon or rectum. Small polyps are usually benign (not cancerous). However, over time, cells in a type of polyp known as an adenomatous polyp (also called an adenoma) can change and become cancerous. The longer a polyp is there and the larger a polyp grows, the more likely this is to happen. 

  • Colorectal cancers usually start when polyp cells begin growing abnormally. As a cancerous tumor grows, it can invade into the deeper layers of the colon or rectal wall. In time, cancer can grow beyond the colon or rectum and into nearby organs or it can spread to nearby lymph nodes. The cancer cells can also travel to other parts of the body. This is known as metastasis. The earlier a cancerous tumor is removed, the better the chance of preventing its spread.

Treatment choices for colon and rectal cancer

You and your healthcare provider will discuss a treatment plan that’s best for your needs.

  • Surgery is often done to remove the cancerous parts of the colon and rectum. Some surrounding tissue is removed as well, possibly including nearby lymph nodes.

  • Chemotherapy may be done in addition to surgery, or instead of surgery if the cancer is advanced. This therapy uses medicines to attack cancer cells. It is considered systemic therapy because it works throughout the body. It's usually done as an outpatient procedure in a healthcare provider's office, clinic, or hospital. You may receive the medicine in pill form or through an IV line or infusion pump (a device that slowly releases medicine into your bloodstream).

  • Radiation therapy may be done, especially for rectal cancer. This treatment uses high-energy X-rays to kill cancer cells. It’s considered localized therapy because it targets the specific area of the body affected by the cancer. It is usually performed on an outpatient basis in a hospital or radiation clinic.

  • Targeted therapy uses drugs that target proteins or cell functions that help cancer cells grow. Some of these drugs are given along with chemotherapy drugs, while others are used by themselves. 

Treatment Choices

Colorectal Cancer: Treatment Choices

There are various treatment choices for colorectal cancer. Which may work best for you? It depends on a number of factors. These include the type, size, location, and stage of your cancer. Factors also include your age, overall health, and what side effects you’ll find acceptable.

Learning about your treatment options

You may have questions and concerns about your treatment options. You may also want to know how you’ll feel and function after treatment, and if you’ll have to change your normal activities.

Your healthcare provider is the best person to answer your questions. He or she can tell you what your treatment choices are, how successful they’re expected to be, and what the risks and side effects are. Your healthcare provider may advise a specific treatment. Or he or she may offer more than one, and ask you to decide which one you’d like to use. It can be hard to make this decision. It is important to take the time you need to make the best decision.

Deciding on the best plan may take some time. Talk with your healthcare provider about how much time you can take to explore your options. You may want to get another opinion before deciding on your treatment plan. In fact, some insurance companies may require a second opinion. In addition, you may want to involve your family and friends in this process.

Understanding the goals of treatment for colorectal cancer

For many colorectal cancers, the goal of treatment is to cure the cancer. If cure is not possible, treatment may be used to shrink the cancer or keep it under control for as long as possible. Treatment can also improve your quality of life by helping control the symptoms of the disease. The goals of colorectal cancer treatment can include:

  • Remove the cancer in the colon or rectum

  • Remove or destroy tumors in other parts of the body

  • Kill or stop the growth or spread of colorectal cancer cells

  • Prevent or delay the cancer's return

  • Ease symptoms from the cancer, such as pain or eating problems caused by pressure on organs

Types of treatment for colorectal cancer

Several types of treatment can be used for colorectal cancer. Different combinations of treatment may be used, depending on the stage of the cancer and other factors. Each treatment has its own goals. Here is an overview of each type of treatment:


This is the most common treatment for most early stages of colon and rectal cancer. The goal of surgery is to remove the entire tumor and any cancer cells that may have spread to nearby tissue. Depending on the stage of the cancer, surgery may be all that's needed. Or surgery may come before or after another treatment is used.


The goal of chemotherapy is to stop cancer from growing or spreading. It does this by using medicines to either kill the cells or stop them from dividing. If the medicines are given in a way that lets them enter the bloodstream, they treat cancer cells throughout the body. That way they can treat cancer that has spread. This type of treatment is called systemic. Medicines can also be given to attack cancer cells in specific organs, such as the liver. This treatment is called local. Chemotherapy might also be used before surgery to shrink tumors. When used before surgery, it is called neoadjuvant therapy. It might be used after surgery to kill or control any remaining cancer cells. When used after surgery, it is called an adjuvant therapy.

Radiation therapy

The goal of radiation therapy is to kill cancer cells using high-energy X-rays. It has a major role in treating rectal cancers, but it may be used in some colon cancers as well. Like chemotherapy, it may be used before surgery to shrink tumors. This treatment is called neoadjuvant radiation therapy. This may lower the chance that a person will need a permanent colostomy. When it's used after surgery, it is called adjuvant radiation therapy. Then the goal is to reduce the chance that the cancer will come back.

Targeted therapy

This type of therapy uses medicines that target proteins or cell functions that help cancer cells grow. Some of these medicines are given along with chemotherapy medicines, while others are used by themselves. The goal is to prevent the cancer from growing. It may also be used to help chemotherapy get inside the tumor. This can help it be more effective.


The goal of this type of treatment is to help the body's own immune system attack the cancer cells. Medicines called checkpoint inhibitors can be used to treat some advanced colorectal cancers in which the cells have certain gene changes. This treatment might be an option for some people who have already had chemotherapy.

Ablation and embolization

These methods can be used to treat tumors that have spread to other parts of the body, such as the liver or lungs. Ablation is the use of heat, cold, or other methods to destroy tumors rather than removing them. For embolization, a substance is injected into a blood vessel to try to cut off a tumor's blood supply or to deliver chemotherapy or radiation directly to the tumor.

Supportive care

Your healthcare provider may advise therapies that help ease your symptoms, but don’t treat the cancer. These can sometimes be used along with other treatments. Or your healthcare provider may suggest supportive care if he or she believes that available treatments are more likely to do you more harm than good.

Clinical trials for new treatments

Researchers are always looking for new ways to treat cancer. These new methods are tested in clinical trials. Talk with your healthcare provider to find out if there are any clinical trials you should consider.

Talking with your healthcare provider

At first, thinking about treatment options may seem overwhelming. Talk with your healthcare providers, nurses, and loved ones. Make a list of questions. Consider the benefits and possible side effects of each option. Discuss your concerns with your healthcare provider before making a decision.


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Robert C Amajoyi, MD

Colon and Rectal Surgery, Surgery (General)

Benjamin J Kulow, MD

Colon and Rectal Surgery, Surgery (General)

Timothy J Pluard, MD

Oncology / Hematology

Shahzad Raza, MD

Oncology / Hematology

Jamie P Rigden, MD

Oncology / Hematology

Ali Shwaiki, MD

Oncology / Hematology

Jacob P Smeltzer, MD

Oncology / Hematology

Janakiraman Subramanian, MD

Oncology / Hematology

Addison R Tolentino, MD

Oncology / Hematology

Saint Luke’s Cancer Institute

Saint Luke's provides comprehensive cancer care, from expert diagnosis and personalized treatment plans to survivorship support.