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Colorectal Cancer

Table of Contents

woman suffering from colorectal cancer

Colorectal cancer is cancer that forms in the colon or rectum. The colon is the biggest part of the large intestine. The rectum is the piece that connects the colon to the anus. Both the colon and the rectum are part of the digestive system. They help remove solid waste from the body. Sometimes colorectal cancer is called colon cancer or rectal cancer, depending on where it starts. The 2 cancers are looked at together because their treatments are similar. Most colorectal cancers begin as growths called polyps. They can form on the inner lining of the colon or rectum. Most polyps are not cancer, but some develop into cancer over time.

Colorectal cancer is one of the most commonly diagnosed cancers in the U.S. But rates have gone down as more people receive routine colorectal cancer screenings. Some of these screening tests, like colonoscopies, let doctors remove polyps before they can develop into cancer.

The U.S. Preventive Services Task Force and the American Cancer Society recommend that people at average risk for colorectal cancer start screening at age 45.

 

Subtypes of Colorectal Cancer

The 2 main types of colorectal cancer are colon cancer and rectal cancer. Most colorectal cancers are adenocarcinomas. They begin in the gland tissue that lines the organs. They start as adenoma polyps that are harmless at first but grow into cancer over time.

Rarely, the following cancers may be found in the colorectal area:

  • Carcinoid – These cancers start in the cells that make hormones in the intestine. They are also called neuroendocrine tumors (NETs). They grow slowly and may be treated with surgery or hormone therapy.
  • Gastrointestinal stromal tumors (GIST) – These tumors can form anywhere in the GI tract but seldom show up in the colon. They are soft tissue sarcomas, which means they start in the soft tissue that connects bones or muscles. When they develop into cancer, they are considered sarcomas and are treated as such.
  • Lymphoma – Lymphoma is a blood cancer that can start in the colon. Even if the cancer is found in the colon, it is treated as lymphoma. Colorectal lymphoma is rare.

 

Risk Factors

The risk of colorectal cancer increases with age. Colorectal cancer is much more common after age 50.

Some risk factors for colorectal cancer are lifestyle factors that can be changed. These include:

  • Being overweight or having obesity
  • Little or no physical activity
  • Moderate to heavy alcohol use
  • Smoking
  • Eating a lot of red or processed meat
  • Not getting enough calcium
  • Not eating enough whole grains, fruit, and vegetables

Other risk factors that cannot be changed include:

  • A personal history of polyps in the colon
  • Family history of colorectal cancer and/or polyps
  • A personal history of ovarian cancer, endometrial cancer (cancer in the lining of the uterus), or breast cancer
  • Chronic inflammatory bowel disease (ulcerative colitis or Crohn’s dis­ease)
  • Type 2 diabetes
  • Inherited genetic conditions, such as familial adenomatous polyposis (FAP) and Lynch syndrome. Lynch syndrome is the most common inherited form of colorectal cancer. This is also known as hereditary nonpolyposis colorectal cancer (HNPCC). It accounts for about 2% to 4% of all colorectal cancers.

Having an inherited genetic condition or a family history of colorectal cancer can affect screening. These conditions can impact the age you should begin screening, the type of screening you receive, and how often you are screened.

Signs and Symptoms

Many people with colorectal cancer have no symptoms at all. That’s because symptoms often occur when the cancer is more advanced.

Possible signs of colorectal cancer include:

  • Blood (either bright red or very dark) in the stool
  • Change in bowel habits
  • Constant tiredness or anemia
  • Diarrhea, constipation, or feeling that the bowel does not empty completely
  • General abdominal discomfort (frequent gas pains, bloating, fullness, or cramps)
  • Stools that are narrower than usual
  • Vomiting
  • Weight loss with no known reason

If you have these symptoms, it is important to see your doctor for a physical examination, blood tests, and a colonoscopy.

Duration: 42 min

Colorectal Cancer: What You Need to Know When Newly Diagnosed

Did you recently find out you or a loved one has colorectal cancer? Watch the Colorectal Cancer Alliance’s Stephanie Rouse and the Cancer Support Community’s Danelle Johnston talk about the top 10 things you should know about colorectal cancer…

Diagnosis & Staging

Diagnosis

To diagnose colorectal cancer, your doctor will likely give you the following tests:

Physical exam: During the exam, your doctor will look for tenderness, swelling, or unusual growths in your rectum. Your doctor will also check the rest of your body to look for signs of spread to other sites and to evaluate your overall health.

Colonoscopy: Your doctor may want to look at your colon and rectum. This will require a colonoscopy. Your doctor will tell you how to prepare at home the night before this screening. During the colonoscopy, your doctor will insert a camera on a long, flexible tube through your anus and rectum and into your colon to look at it. They also will remove any polyps and take samples of any other abnormal-looking tissue from your colon. This is called a biopsy. Another doctor called a pathologist will look at the samples under a microscope to search for cancer.

Blood tests: Your doctor will ask for a complete blood count (CBC) to get a picture of your overall health. The CBC shows information about your red blood cell count. Because many people with colorectal cancer lose blood in their stool, even if they cannot see it, your red blood cell count may be low. This is called anemia. Your doctor can treat anemia to help you feel stronger and less tired.

Your blood can also be tested for carcinoembryonic antigen (CEA) and circulating tumor DNA (ctDNA). CEA is a protein made by cancer cells. Your doctor may want to test your blood for CEA before starting treatment and then again during treatment to see if it is working. By testing your blood for ctDNA, you doctor can see if there is tumor DNA present in your bloodstream.

Imaging tests (Scans): These tests allow your doctor to see if the cancer has spread to other parts of the body. You may have a CT scan of your chest, abdomen, and pelvis. Your doctor may also request MRI scans. If you have rectal cancer, you may have an endoscopic ultrasound test. Chest x-rays and PET scans are not routinely used for colorectal cancer. But your doctor may order them if they want to get more information about potential spread of the cancer.

Biomarker testing of your tumor tissue: Your doctor may test your tumor tissue removed during a biopsy or surgery for biomarkers. These tests can help your doctors understand which treatments are right for you and whether your cancer is inherited.

  • All colorectal cancer patients should ask their doctor if they have been tested for MSI-High (microsatellite instability) or dMMR (deficient mismatch repair). If you test MSI-High or dMMR positive, your doctor may give you an additional test to see if your cancer is inherited. This second test will check for genes that increase risk of cancer in family members, such as Lynch syndrome.
  • If you test positive for PIK3CA (PI3 kinase), you may benefit from taking aspirin after colorectal cancer surgery.
  • Patients with advanced or metastatic colorectal cancer should ask their doctor if they have been tested for KRAS, HER2, NRAS, and BRAF. These tests help your doctor decide which treatments are most likely to work for you.

Surgery: Your final diagnosis and cancer stage may not be known until after you have surgery. During the surgery, a surgeon will remove the tumor itself, as well as tissue around the tumor (called margins). They may also remove the fat and lymph nodes attached to the area where the tumor was found. A pathologist will look at the tissue that was removed during surgery to help determine the stage of the cancer.

 

Staging

A cancer’s “stage” is a measure of how far it has spread. The stage of colorectal cancer depends on three factors:

  • Tumor: How far has the tumor grown from the inner lining of the colon through the layers of its walls.
  • Nodes: Whether cancer cells are found in the lymph nodes near the site of the cancer and how many nodes are affected. Lymph nodes are small, bean-shaped structures found throughout the body. They filter substances in a fluid called lymph and help fight infection and disease.
  • Metastasis: Whether cancer has spread beyond the colon and its nearby tissues to distant organs like the lungs, liver, bones, or brain.

Each factor is assigned a number. The letter X is used for factors that cannot be measured. For example, a tumor could be T3, N2, and M0. The numbers are grouped to assign a stage, 0 through IV (0 to 4). Four means that the cancer that has grown and spread the most.

 

Colon Cancer Stages

  • Stage 0: The cancer is found only in the inner lining of the colon.
  • Stage I: The cancer has spread to the middle layers of the colon wall.
  • Stage II
    • Stage IIA: Cancer has grown into the outer layer of the colon but has not gone through it.
    • Stage IIB: The cancer has grown through the wall of the colon or rectum but has not grown into other nearby tissues or organs. It has not spread to the neighboring lymph nodes.
    • Stage IIC: The cancer has started to grow in nearby tissues or organs.
  • Stage III
    • Stage IIIA: Cancer has spread to the middle layers of the colon wall and has spread to as many as 3 lymph nodes. Or, the cancer has not yet spread to the middle layer of the colon wall but involves 4-6 lymph nodes.
    • Stage IIIB: Cancer has spread to as many as 3 nearby lymph nodes. It also has spread to the outer layers of the colon wall into nearby fat or organs or through the peritoneum. (The peritoneum is a thin membrane that lines the inside of the abdomen.)
    • Stage IIIC: Cancer has spread to 4 or more nearby lymph nodes. It also has spread to or beyond the outer layer of the colon wall, to nearby fat or organs, or through the peritoneum.
  • Stage IV: The cancer has spread to other parts of the body, such as the liver or lungs. Stage IV is divided into IVA, IVB, and IVC depending on the number of distant organs or body parts involved. Stage IVA involves one distant organ. Stage IVB cancer has spread to 2 or more distant organs. In stage IVC, the cancer has spread to the peritoneum. Stage IV (4) is also called advanced or metastatic cancer.

 

Rectal Cancer

  • Stage 0: The cancer is found only in the inner lining of the rectum.
  • Stage I: The cancer has spread to the middle layers of the rectal wall. It has not spread to the outer wall of the rectum or outside of the rectum.
  • Stage II
    • Stage IIA: Cancer has grown into the outer layer of the rectum but has not gone through it.
    • Stage IIB: The cancer has grown through the wall of the rectum but has not grown into other nearby tissues or organs. It has not spread to the neighboring lymph nodes.
    • Stage IIC: The cancer has started to grow in nearby tissues or organs.
  • Stage III: The cancer has spread to nearby lymph nodes, but it has not spread to other parts of the body.
    • Stage IIIA: The cancer has spread to the middle layers of the rectum wall and has spread to as many as 3 lymph nodes. Or, the cancer has not yet spread to the middle layer of the rectum wall but involves 4-6 lymph nodes.
    • Stage IIIB: The cancer has spread to as many as 3 nearby lymph nodes. It also has spread to the outer layers of the rectum wall into nearby fat or organs or through the peritoneum. (The peritoneum is a thin membrane that lines the inside of the abdomen.)
    • Stage IIIC: The cancer has spread to 4 or more nearby lymph nodes. It also has spread to or beyond the outer layer of the rectum wall, to nearby fat or organs, or through the peritoneum.
  • Stage IV: The cancer has spread to other parts of the body, such as the liver or lungs. Stage IV is divided into IVA, IVB, and IVC depending on the number of distant organs or body parts involved. Stage IVA involves one distant organ. Stage IVB cancer has spread to 2 or more distant organs. In stage IVC, the cancer has spread to the peritoneum. Stage IV (4) is also called advanced or metastatic cancer.

 

Grading

Your doctor may assign a grade (G) to the cancer. The grade is a number between 1 and 43 that describes how the cancer cells look under a microscope. The cancer cells are compared to normal cells. The higher the number, the less the cells look like normal cells. GX is used when grading is not possible. The grade helps your doctor understand how fast the cancer is growing and how likely it is to spread. Cancer that is growing fast is described as aggressive.

Treatment & Side Effects Management

Treatment for colorectal cancer will depend on several factors. This includes the stage and location of the cancer and your overall health. You will want to also keep in mind your preferences and goals of care. It is important for you and your doctor to decide together what treatment is best for you. It is also OK to get a second opinion. Another doctor can confirm your diagnosis and talk with you about other treatment options. Having a second opinion can help you feel confident in your choices.

You do not have to rush to make a decision about your treatment. Ask questions if you do not understand anything about your treatment or the terms your doctors are using. Bring someone along to appointments for support or to take notes. Consider asking if you can record your conversations with your doctor. It’s a lot of information to take in at one time. Having the recording will allow you to re-listen to the conversation as you consider your options. You may also want to speak with an oncology nurse or nurse navigator. They can help you understand your options, connect you with services, and provide you with support.

The main types of treatment for colorectal cancer are:

Surgery is usually the first treatment for colon cancer and for some rectal cancers. The goal of surgery is to remove as much of the cancer as possible.

 

Learn More About Surgery for Colorectal Cancer

Ablation is any treatment that destroys tissue. For CRC, it is used to treat small tumors. These tumors have usually spread to other parts of the body, like the liver.

There are different types of ablation treatment. Cryoablation freezes cancer cells to destroy them. Radiofrequency ablation uses electric currents and heat to kill cancer cells. During treatment, the probe is placed into the tumor. This is either through the skin or through a cut in the body. The probe sends heat and currents to the cancer cells.

Ablation may cause soreness at the site and abdominal pain. It can also cause severe side effects. This may include fever, liver infection, or internal bleeding.

Radiation therapy is the use of high-energy rays to kill or damage cancer cells. The goal is to damage as many cancer cells as possible without harming healthy tissue. To lessen damage, doses are very precise, and treatment is often spaced out.

Radiation is a common treatment for rectal cancer. It is a less common treatment for colon cancer. It often takes the form of external beam radiation. The radiation is given by a machine outside of the body. Less often, internal radiation (brachytherapy) is used. The radiation is placed in the body through the rectum.

Common side effects include fatigue, burning or soreness at the site of the radiation, and loose or bloody stools. Radiation to the pelvic area can affect sexual health or fertility. If you still plan to have biological children, ask about fertility before you start treatment.

Chemotherapy (also called chemo) uses drugs to destroy or damage fast-growing cells like cancer cells. It is used to shrink tumors, slow cancer’s growth, relieve symptoms, or help people live longer. 

 

Learn More About Chemotherapy for Colorectal Cancer

During chemoradiation you are given chemotherapy and radiation at the same time. It is used to treat locally advanced rectal cancer. Chemoradiation can be given before surgery. This will help shrink the tumor. The chemotherapy weakens the tumor cells. This makes them more sensitive to radiation. 

This treatment may cause side effects related to both chemotherapy and radiation.

Immunotherapy works with the body’s immune system to find, attack, and kill cancer cells. These drugs can work in different ways. Some boost the immune system, so it can fight cancer better. Other immunotherapy drugs help the immune system better recognize cancer cells.

A small number of people with colorectal cancer will be given immunotherapy as a treatment option.

 

Learn More About Immunotherapy for Colorectal Cancer 
 

Targeted therapy uses drugs to target specific changes in cancer cells that help them grow, divide, and spread. Targeted therapy drugs are designed to be more precise. They fight cancer cells while causing less harm to other cells in the body. 

 

Learn More About Targeted Therapy for Colorectal Cancer 
 

Duration: 6 min

Immunotherapy Side Effects

If you or your loved one is interested in immunotherapy, it is important to know about the possible side effects of immunotherapy treatments. Immunotherapy side effects are generally different from the side effects of other cancer treatments, like…

Coping With Colorectal Cancer

An important step in managing your colorectal cancer and its treatment is to be informed. Cancer is a complex and challenging disease that is treated in many different ways. The more you know about your colorectal cancer diagnosis, treatment options, and possible side effects the easier it will be to talk with your health care team to determine the best treatment plan for you. Colorectal cancer can affect all areas of your life, below is a list of resources to help with your general concerns:

Coping With an Ostomy

It takes time to get used to living with an ostomy, and there are a number of changes you may need to make. But after ostomy surgery, you can go on to live an active and healthy life. Here are some tips for coping with an ostomy:

  • Telling people about the ostomy: If you don’t tell people about your ostomy and pouch, they won’t be able to tell you have it. You may need to tell your boss about it because you can’t lift heavy items, or because you need to go to the bathroom often to manage the ostomy pouch.
  • Caring for the ostomy: You should change your pouch every 3 to 7 days. If you have itching or burning, it means you should change the wafer (the part that goes against the skin and has a hole that fits around your stoma). If you wear a pouch for too long, it may damage your skin.
  • Emergency supply kit: Carry an emergency kit with supplies such as pouches, extra pre-cut flange, a roll of tape, a mirror, wet wipes, and cotton swabs.
  • Showering and bathing: You can bathe with or without the pouch in place. If you want to take a shower or bath with the pouch off, you can. You can leave the pouch on while bathing or cover it with plastic to keep it dry.
  • Clothing to hide the ostomy: It may take a while to find a look you are comfortable with that works with a pouch, but there are more options now than ever before. You can help hide your pouch by wearing loose-fitting tops and bottoms. You may find belts or some waistbands uncomfortable. Clothes with higher or looser waistbands may work better. You can buy ostomy swimsuits through specialty shops and websites.
  • Odor control: You can buy liquid and solid products to help control the odor of the pouch. Certain foods (such as asparagus, fish, garlic, and onions) can cause a stronger urine odor. You can lessen that by drinking more water or cranberry juice. Empty your pouch often. Always empty the pouch before you leave the house and when you will be away from a convenient toilet.
  • Diet changes: You may want to limit foods and drinks that cause gas. These can include asparagus, beans, beer, broccoli, Brussels sprouts, cabbage, carbonated beverages, cauliflower, onions, and peas.
  • Physical activity: You can go back to most physical activity after you heal from ostomy surgery. Talk with your doctor about the activities you want to do. They can advise on how and when to do them safely. Your doctor may suggest staying away from contact sports to avoid injuring the stoma. If you want to do contact sports, talk to your doctor or ostomy nurse. They can recommend special products and things you can do to protect your stoma while you play. If you lift weights, ask your doctor when it is safe to start again. You can buy a special belt or binder to hold your ostomy bag in place for running, swimming, or other athletic activities. This can help prevent the ostomy bag from loosening and causing a leak.
  • Traveling with an ostomy: Pack extra supplies when you travel. If you are flying, keep some supplies in your carry-on bag in case your checked luggage gets lost. Limit what you eat before you travel.
BlueHQ, Colorectal Cancer Alliance
Take control of your colorectal cancer journey with BlueHQ, a free support service for patients and caregivers powered by the Colorectal Cancer Alliance.
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  • Track treatments and office visits 
  • Access support from the Alliance

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