What is colon cancer?

Your colon, also called the large intestine, is part of your digestive system. It helps to remove waste from your body. If cells within your colon grow too fast, you can develop colon polyps, and those polyps can lead to cancer.

Symptoms and diagnosis

Detecting colon cancer

Colon cancer usually starts with the development of growths inside the colon. These growths are called colon polyps, which can become cancerous. 

If you have early-stage colon cancer, you might not have any symptoms. If symptoms do occur, they could include:

  • Abdominal pain

  • Bleeding

  • Change in bowel habits

  • Weakness or tiredness

  • Unexplained weight loss

Tests used to diagnose colon cancer include

This is the most reliable test for finding polyps. It involves looking at your colon and rectum with a video camera attached to a long, flexible tube. After you undergo a bowel cleansing procedure, a doctor passes the tube through your rectum and colon.

These tests involve you providing a stool sample. Doctors examine the sample for hidden blood or altered DNA. These may be signs of polyps or cancer.

The test involves passing a thin, lighted tube through your rectum. Doctors use it to looks for polyps in the portion of your colon closest to your rectum and your rectum itself. The rectum is the lowest portion of your colon where your body stores stool. Like a colonoscopy, this test requires bowel cleansing beforehand.

This test uses a CT scan to view your colon after a bowel cleansing procedure.

Tests and prevention

Screening as prevention

The cause of most colon cancers is not known. But there are known risk factors for developing colon cancer. Older adults, African-Americans and people with a family history of colon cancer are at increased risk.

Other risk factors include:

  • Diabetes

  • Heavy alcohol use

  • History of colon polyps

  • Inactive lifestyle

  • Inflammatory intestinal conditions, including Crohn’s disease and ulcerative colitis

  • Low-fiber, high-fat diet

  • Obesity

  • Previous abdominal radiation

  • Smoking

Having regular colonoscopy screenings is the best way to prevent colon cancer. Doctors recommend routine colonoscopies beginning at age 50. If you have a family history of colon cancer or other known risk factors, your doctor might suggest earlier screenings. 

Treatments and research

Advanced colon cancer treatment

If you have colon cancer, you might need surgery. The type of surgery you will need depends on the size of your cancer.

For smaller cancers, your doctor might recommend a polypectomy.

Some cancerous polyps can be removed during a colonoscopy. The removal of polyps is called a polypectomy. If polyps can't be removed during a colonoscopy, your surgeon might recommend minimally invasive laparoscopic surgery. During this procedure, surgeons make small incisions in your abdomen. These incisions are used to insert a tiny camera and special surgical instruments.

For larger cancerous polyps that cannot be removed through a polypectomy, your doctor may recommend a colectomy.

During this procedure, surgeons remove the cancer and some healthy tissue around the cancer. A colectomy is also called a segmental resection. Some colectomy surgeries are performed laparoscopically. During a laparoscopic procedure, a surgeon makes small incisions in your abdomen. These incisions are used to insert a tiny camera and special surgical instruments.

Others might require a traditional open surgery approach. Later-stage cancers could require a total colectomy. During a total colectomy, surgeons remove the entire colon. After a colectomy, your surgeon will repair the function of the colon. This can include the creation of an opening in your abdomen (stoma) so waste can leave your body.

Additional treatments

Many people with colon cancer will need additional treatments before or after surgery. These include:

Medication treatments for colon cancer include chemotherapy, targeted therapy and immunotherapy. Chemotherapy works by killing cancer cells. Targeted therapy slows cancer cell growth. Immunotherapy makes your immune system attack cancer cells.

Radiation therapy uses radiation to kill cancer cells.

Advancing our understanding of colon cancer

We want to prevent cancer and find better treatments. To do this, colon cancer experts at UW Health and the UW Carbone Cancer Center conduct laboratory research and clinical trials.

Find a clinical trial

Meet our team

A dedicated team of experts

At UW Health and the UW Carbone Cancer Center, we work together to provide the exact care you need, when you need it. 

Our team includes:

  • Colorectal surgeons

  • Digestive disease specialists

  • Genetic counselors

  • Integrative medicine physicians

  • Medical oncologists

  • Nutritionists

  • Palliative care professionals

  • Pathologists

  • Psychologists

  • Radiation oncologists

  • Social workers

Medical oncology
Radiation oncology


A national leader in cancer care

If you have colon cancer, you will be cared for by doctors and surgeons within the UW Carbone Cancer Center.

The UW Carbone Cancer Center is designated as a Comprehensive Cancer Center by the National Cancer Institute. This is the highest designation given by the nation’s leading cancer research group. 

Our team offers advanced colon cancer treatments at UW Health in Madison, Wis. 

  • UW Carbone Cancer Center
    • 600 Highland Ave. / Madison, WI
    • Closed now
    • The University of Wisconsin Carbone Cancer Center is a pioneer in cancer research and quality patient care. It is the only comprehensive cancer center in Wisconsin, as designated by the National Cancer Institute.

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  • UW Carbone Cancer Clinic - 1 S. Park
    • 1 S. Park St. / Madison, WI
    • (608) 287-2552
    • Closed now
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  • SwedishAmerican Regional Cancer Center
    • 3535 N Bell School Road / Rockford, IL
    • (779) 696-9400
    • Closed now
    • Patients here have convenient local access to UW Health cancer specialists in areas such as breast cancer, head-and-neck cancer, endocrine cancer, and thoracic surgical and abdominal surgical oncology.

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  • Beloit Cancer Center
    • 1670 Lee Lane / Beloit, WI
    • Open now
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  • UW Health Johnson Creek
    UW Health Johnson Creek
    UW Cancer Center Johnson Creek
    • 250 Doctors Ct. / Johnson Creek, WI
    • (920) 699-3500
    • Closed now
    • UW Cancer Center Johnson Creek offers the people of southeastern Wisconsin local access to leading-edge research and treatments offered by the University of Wisconsin Carbone Cancer Center in Madison.

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  • UW Cancer Center at ProHealth Care
    • N16 W24131 Riverwood Drive / Waukesha, WI
    • Open now
    • Partnered with the UW Carbone Cancer Center at the University of Wisconsin in Madison, UW Health Cancer Center at ProHealth Care offers world-class cancer care in a comforting setting close to home.

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Patient and support services

Support you can use

The UW Carbone Cancer Center offers many resources for patients and families faced with cancer.

Online resources

UW Carbone Cancer Center

The experts at the UW Carbone Cancer Center intimately understand every type of cancer. We will get to know you and design a treatment plan that works for you and your family.

Learn more