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 45. 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

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UW Health | Carbone Cancer Center
Patient Guide

To help you feel comfortable during your stay at the UW Health | Carbone Cancer Center, we invite you to learn about our facility and the services we offer.

Meet our team

A dedicated team of experts

At the UW Health | 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


A national leader in cancer care

The UW Health | 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. and Rockford, Ill. 

Patient stories

Hope and inspiration

Two women standing next to each other and smiling
Colon cancerKayla receives liver from living donor, Morgan, to combat colorectal cancer
As a pharmacist at an oncology practice, Kayla Love has watched countless people battle tough-to-beat cancers.
Michael Hill (right) with his two sons Oliver (left) and Alex (middle)
Colon cancerMichael receives empathetic care
When Michael Hill was told that he would need surgery to remove a baseball-size tumor from his colon, he had little doubt that his UW Health surgeon, Dr. Ray King, had the training and experience to do the job.

Patient and support services

Support you can use

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

Online resources

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UW Health | Carbone Cancer Center

The experts at the UW Health | 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