Cancer that occurs in your large intestine or rectum is referred to as colorectal cancer. Colon cancer happens when healthy cells become damaged, and grow and divide, spreading cancer in your body.
Most colon cancer starts as polyps (abnormal growths). When they first develop, polyps are noncancerous, but they can become cancerous over time. Polyp removal is important because it can prevent cancer. Screenings, such as colonoscopy, can check for cancer and remove polyps at the same time. You should have colorectal cancer screenings beginning at age 50 (possibly earlier if you have a family history of colorectal cancer).
You Are at Risk for Colorectal Cancer if You:
- Are age 50 or older
- Have a history of adenomatous (noncancerous) polyps or colon cancer
- Have a family history of colon cancer, rectal cancer or polyps
- Have an inherited syndrome such as adenomatous polyposis or Lynch syndrome
- Are African-American
- Have an inflammatory intestinal conditions such as ulcerative colitis or Crohn's disease
- Have diabetes
- Are obese
- Drink to excess
- Have had radiation therapy for cancer in the abdominal area
- Have a sedentary (inactive) lifestyle
- Have a low-fiber, high-fat diet
Most of the time, it's not clear what causes colon cancer.
If you have colon cancer, you might not have symptoms, especially early in the disease. Symptoms vary from person to person depending on the location and size of the cancer.
- Unexplained weight loss
- Rectal bleeding
- Blood in your stool
- Feeling like your bowel isn't empty after a bowel movement
- Change in the consistency of your stool
- Chronic discomfort – gas, abdominal pain, cramps
- Weakness or fatigue
Talk to your doctor if you have changes in your stool or if you have concerns about changes in your health.
Tests your doctor may use to check for colon cancer include:
- Colonoscopy – This is the only colorectal screening test that examines the entire colon and can remove polyps found during the test. There are other colorectal cancer screening tools, but colonoscopy is the gold standard.
- Virtual colonoscopy (CT colonography) – This test is an option if you can't have traditional colonoscopy for some reason. Your doctor inserts a tube into your anus and pumps air through it to make your colon easier to see in CT (computed tomography) images.
If cancer is detected, your doctors will stage it (determine how advanced it is). Staging is important to decide the right treatment. You may have imaging tests such as CT to stage your cancer. Often, colon cancer cannot be accurately staged until you have surgery.
Colon cancer stages are:
- Stage I: Grown past the lining (mucosa) of your colon or rectum but not past the wall of the colon or rectum
- Stage II: Grown into the wall of the colon or rectum but not to nearby lymph nodes
- Stage III: Spread to nearby lymph nodes but hasn't affected other parts of your body
- Stage IV: Spread elsewhere in your body such as your liver or lungs
Your treatment depends on the stage of your cancer. Usually, treatment includes surgery, chemotherapy and radiation or a combination of those treatments. Our gastroenterology specialists are experienced in treating every colorectal condition, including colorectal cancer. Learn more about Aurora's colorectal cancer program and treatments.
The surgery you might have for colorectal cancer depends on how advanced your cancer is.
- Early-stage (small, confined in a polyp) – Your cancer may be removable during a colonoscopy or endoscopic mucosal resection (EMR). Some polyps have to be removed with minimally invasive (laparoscopic) surgery. Your doctor may remove lymph nodes for testing during this procedure. You may not need additional treatment if your doctors determine that the cancer has been completely removed.
- Invasive (grown into or through the colon) – You may have a colectomy to remove the cancerous part of your colon and some surrounding tissue. Your lymph nodes are removed for testing, too. Your doctor connects the parts of your colon around where the tumor was removed. In some cases, reconnection isn't possible, and your doctor creates an opening (colostomy) in your abdomen for waste elimination into a bag – either temporarily or permanently.
- Advanced – You may have surgery to treat symptoms including pain, bleeding or a blockage. If your cancer has spread and your health remains relatively good, your doctor may recommend removing the cancer and treating you with chemotherapy.
Chemotherapy uses medications to kill cancer cells. You might have chemotherapy:
- After you've had surgery to remove cancer in order to prevent recurrence of cancer that has spread to your lymph nodes
- To shrink a tumor before you have surgery
- To treat symptoms of your colorectal cancer that has spread to other parts of your body
Radiation kills cancer cells with forms of energy. You are more likely to have radiation therapy for colorectal cancer if yours is more advanced and has spread through the wall of your rectum or to lymph nodes. You might need radiation therapy:
- To kill cancer cells in your body after you've had surgery to treat your colorectal cancer
- To shrink a tumor before you have surgery
- To treat your symptoms of colorectal cancer
- To decrease the risk of your cancer recurring in the area where it began (in combination with chemotherapy)
If your colorectal cancer is very advanced, your doctor may recommend targeted drug therapy. These drugs are prescribed to prevent cancer from growing and are used with or without chemotherapy. They don't help everyone with advanced colorectal cancer.
How to Prevent Colorectal Cancer
Most colon cancer starts as polyps. Polyp removal is so important because it can prevent cancer.
When they first develop, polyps are noncancerous. Adenomatous polyps can become cancerous over time. You should have colorectal cancer screenings beginning at age 50 (possibly earlier if you have a family history of colorectal cancer). Screenings, such as colonoscopy, can check for cancer and remove polyps at the same time.
Talk to your doctor about which colon cancer screening test and schedule is right for you.
Your diet and lifestyle can affect your colorectal cancer risk. Follow these steps to reduce your risk:
- Don't use tobacco. Talk to your doctor about ways to quit.
- Don't drink alcohol to excess. If you drink alcohol, limit yourself to a maximum of one drink per day (women) or two drinks per day (men).
- Eat healthy – a variety of vegetables, fruits and whole grains.
- Keep a healthy weight.
- Be active – exercise for at least 30 minutes most days.