Colon cancer - Diagnosis and treatment (2023)

Diagnosis

Screening for colon cancer

Doctors recommend certain screening tests for healthy people with no signs or symptoms in order to look for signs of colon cancer or noncancerous colon polyps. Finding colon cancer at its earliest stage provides the greatest chance for a cure. Screening has been shown to reduce your risk of dying of colon cancer.

Doctors generally recommend that people with an average risk of colon cancer begin screening around age 45. But people with an increased risk, such as those with a family history of colon cancer or African-American heritage, should consider screening sooner.

Several screening options exist — each with its own benefits and drawbacks. Talk about your options with your doctor, and together you can decide which tests are appropriate for you. If a colonoscopy is used for screening, polyps can be removed during the procedure before they turn into cancer.

Diagnosing colon cancer

If your signs and symptoms indicate that you could have colon cancer, your doctor may recommend one or more tests and procedures, including:

• Using a scope to examine the inside of your colon (colonoscopy). Colonoscopy uses a long, flexible and slender tube attached to a video camera and monitor to view your entire colon and rectum. If any suspicious areas are found, your doctor can pass surgical tools through the tube to take tissue samples (biopsies) for analysis and remove polyps.

• Blood tests. No blood test can tell you if you have colon cancer. But your doctor may test your blood for clues about your overall health, such as kidney and liver function tests.

  Your doctor may also test your blood for a chemical sometimes produced by colon cancers (carcinoembryonic antigen, or CEA). Tracked over time, the level of CEA in your blood may help your doctor understand your prognosis and whether your cancer is responding to treatment.

Determining the extent of the cancer

If you've been diagnosed with colon cancer, your doctor may recommend tests to determine the extent (stage) of your cancer. Staging helps determine what treatments are most appropriate for you.

Staging tests may include imaging procedures such as abdominal, pelvic and chest CT scans. In many cases, the stage of your cancer may not be fully determined until after colon cancer surgery.

The stages of colon cancer are indicated by Roman numerals that range from 0 to IV, with the lowest stages indicating cancer that is limited to the lining of the inside of the colon. By stage IV, the cancer is considered advanced and has spread (metastasized) to other areas of the body.

Treatment

Which treatments are most likely to help you depends on your particular situation, including the location of your cancer, its stage and your other health concerns. Treatment for colon cancer usually involves surgery to remove the cancer. Other treatments, such as radiation therapy and chemotherapy, might also be recommended.

Surgery for early-stage colon cancer

If your colon cancer is very small, your doctor may recommend a minimally invasive approach to surgery, such as:

• Removing polyps during a colonoscopy (polypectomy). If your cancer is small, localized, completely contained within a polyp and in a very early stage, your doctor may be able to remove it completely during a colonoscopy.
• Endoscopic mucosal resection. Larger polyps might be removed during colonoscopy using special tools to remove the polyp and a small amount of the inner lining of the colon in a procedure called an endoscopic mucosal resection.
• Minimally invasive surgery (laparoscopic surgery). Polyps that can't be removed during a colonoscopy may be removed using laparoscopic surgery. In this procedure, your surgeon performs the operation through several small incisions in your abdominal wall, inserting instruments with attached cameras that display your colon on a video monitor. The surgeon may also take samples from lymph nodes in the area where the cancer is located.

Surgery for more advanced colon cancer

If the cancer has grown into or through your colon, your surgeon may recommend:

• Partial colectomy. During this procedure, the surgeon removes the part of your colon that contains the cancer, along with a margin of normal tissue on either side of the cancer. Your surgeon is often able to reconnect the healthy portions of your colon or rectum. This procedure can commonly be done by a minimally invasive approach (laparoscopy).

• Surgery to create a way for waste to leave your body. When it's not possible to reconnect the healthy portions of your colon or rectum, you may need an ostomy. This involves creating an opening in the wall of your abdomen from a portion of the remaining bowel for the elimination of stool into a bag that fits securely over the opening.

  Sometimes the ostomy is only temporary, allowing your colon or rectum time to heal after surgery. In some cases, however, the colostomy may be permanent.

• Lymph node removal. Nearby lymph nodes are usually also removed during colon cancer surgery and tested for cancer.

Surgery for advanced cancer

If your cancer is very advanced or your overall health very poor, your surgeon may recommend an operation to relieve a blockage of your colon or other conditions in order to improve your symptoms. This surgery isn't done to cure cancer, but instead to relieve signs and symptoms, such as a blockage, bleeding or pain.

In specific cases where the cancer has spread only to the liver or lung but your overall health is otherwise good, your doctor may recommend surgery or other localized treatments to remove the cancer. Chemotherapy may be used before or after this type of procedure. This approach provides a chance to be free of cancer over the long term.

Chemotherapy

Chemotherapy uses drugs to destroy cancer cells. Chemotherapy for colon cancer is usually given after surgery if the cancer is larger or has spread to the lymph nodes. In this way, chemotherapy may kill any cancer cells that remain in the body and help reduce the risk of cancer recurrence.

Chemotherapy might also be used before an operation to shrink a large cancer so that it's easier to remove with surgery.

Chemotherapy can also be used to relieve symptoms of colon cancer that can't be removed with surgery or that has spread to other areas of the body. Sometimes it's combined with radiation therapy.

For some people with low-risk stage III colon cancer, a shorter course of chemotherapy after surgery may be possible. This approach may reduce the side effects compared with the traditional course of chemotherapy, and may be just as effective.

Radiation therapy

Radiation therapy uses powerful energy sources, such as X-rays and protons, to kill cancer cells. It might be used to shrink a large cancer before an operation so that it can be removed more easily.

When surgery isn't an option, radiation therapy might be used to relieve symptoms, such as pain. Sometimes radiation is combined with chemotherapy.

Targeted drug therapy

Targeted drug treatments focus on specific abnormalities present within cancer cells. By blocking these abnormalities, targeted drug treatments can cause cancer cells to die.

Targeted drugs are usually combined with chemotherapy. Targeted drugs are typically reserved for people with advanced colon cancer.

Immunotherapy

Immunotherapy is a drug treatment that uses your immune system to fight cancer. Your body's disease-fighting immune system may not attack your cancer because the cancer cells produce proteins that blind the immune system cells from recognizing the cancer cells. Immunotherapy works by interfering with that process.

Immunotherapy is usually reserved for advanced colon cancer. Your doctor might have your cancer cells tested to see if they're likely to respond to this treatment.

Supportive (palliative) care

Palliative care is specialized medical care that focuses on providing relief from pain and other symptoms of a serious illness. Palliative care is provided by a team of doctors, nurses and other specially trained professionals that work with you, your family and your other doctors to provide an extra layer of support that complements your ongoing care.

Palliative care teams aim to improve the quality of life for people with cancer and their families. This form of care is offered alongside curative or other treatments you may be receiving.

When palliative care is used along with all of the other appropriate treatments, people with cancer may feel better and live longer.

Clinical trials

Explore Mayo Clinic studies testing new treatments, interventions and tests as a means to prevent, detect, treat or manage this condition.

Coping and support

A cancer diagnosis can be emotionally challenging. In time, people learn to cope in their own unique ways. Until you find what works for you, you might try to:

• Learn enough about your cancer to feel comfortable making treatment decisions. Ask your doctor to tell you the type and stage of your cancer, as well as your treatment options and their side effects. The more you know, the more confident you'll be when it comes to making decisions about your own care. Look for information in your local library and on reliable websites.
• Keep friends and family close. Keeping your close relationships strong will help you deal with cancer. Friends and family can provide the practical support you'll need, such as helping take care of your home if you're in the hospital. And they can serve as emotional support when you feel overwhelmed.

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

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

Preparing for your appointment

If your doctor suspects you may have colon cancer, you'll likely be referred to specialists who treat colon cancer. You may meet with a number of specialists, including a:

• Doctor who treats digestive diseases (gastroenterologist)
• Doctor who uses medications to treat cancer (oncologist)
• Doctor who removes colon cancer using surgery (surgeon)
• Doctor who uses radiation to treat cancer (radiation oncologist)

Because appointments can be brief, and because there's often a lot of ground to cover, it's a good idea to be well-prepared. Here's some information to help you get ready, and know what to expect from your doctor.

What you can do

• Be aware of any pre-appointment restrictions. At the time you make the appointment, be sure to ask if there's anything you need to do in advance, such as restrict your diet.
• Write down any symptoms you're experiencing, including any that may seem unrelated to the reason for which you scheduled the appointment.
• Write down key personal information, including any major stresses or recent life changes.
• Make a list of all medications, vitamins or supplements that you're taking.
• Consider taking a family member or friend along. Sometimes it can be difficult to take in all the information provided during an appointment. Someone who accompanies you may remember something that you missed or forgot.
• Write down questions to ask your doctor.

Some basic questions to ask your doctor include:

• Where is my colon cancer located in my colon?
• What is the stage of my colon cancer?
• Can you explain my pathology report to me?
• Can I have a copy of my pathology report?
• Has my colon cancer spread to other parts of my body?
• Will I need more tests?
• What are the treatment options for my colon cancer?
• Will any of the treatments cure my colon cancer?
• What is the chance that my colon cancer will be cured?
• How much does each treatment increase my chances that my colon cancer will be cured?
• What are the potential side effects of each treatment?
• How will each treatment affect my daily life?
• Is there one treatment you feel is best for me?
• What would you recommend to a family member or friend in my same situation?
• How much time can I take to make my decision about treatment?
• Should I seek a second opinion?
• Should I see a specialist? What will that cost, and will my insurance cover it?
• Are there any brochures or other printed material that I can take with me? What websites do you recommend?
• Do my siblings or my children have an increased risk of colon cancer?

In addition to the questions that you've prepared to ask your doctor, don't hesitate to ask questions during your appointment.

What to expect from your doctor

Your doctor is likely to ask you a number of questions. Being ready to answer them may allow time to cover other points you want to address. Your doctor may ask:

• When did you first begin experiencing symptoms?
• Have your symptoms been continuous or occasional?
• How severe are your symptoms?
• What, if anything, seems to improve your symptoms?
• What, if anything, appears to worsen your symptoms?
• Do you have a family history of colon cancer or other cancers?