Frequently Asked Questions

The following are some of the most frequently asked questions about colon and rectal cancer screening, diagnosis and treatment, and follow-up care for colon and rectal cancer. 

Screening and Prevention 

Q: What are the signs and symptoms of colon and rectal cancer?

Many of these cancers have no symptoms – which is why screening is so important. When symptoms may occur, they can include blood in the stool, difficulty or pain passing bowel movements and abdominal pain. 

Q: Can I have a colonoscopy without preparation beforehand?

A: No. Your colon must be clean before the procedure to allow for a clear view of the intestine. For more information on preparing for a colonoscopy, please see the “Prior to Procedure” section in our health library entry on colonoscopy. 

Q. Are there any alternatives to colonoscopy for colon and rectal cancer screening?

At the moment, colonoscopy is the best screening test. Some types of X-rays (barium enema) could be used but are generally not as good as colonoscopy. 

Q. What is virtual colonoscopy?

Virtual colonoscopy is a test with an MRI scanner that gives a picture of the inside of the colon like colonoscopy. At the moment, it is still experimental for the detection of colon and rectal cancers. Virtual colonoscopy still requires a “prep” and has the disadvantage that, if something abnormal is found, no biopsies can be done so a regular colonoscopy may be needed regardless. 

Q: Is there a genetic test for colon or rectal cancer?

A small proportion of colon and rectal cancers are associated with mutations in genes that can be passed down from one generation to the next. If your oncologist feels you or your family may be affected by any of these mutated genes, genetic tests can be done to confirm this. 

Q: Do colonics (colon cleansings) help prevent colon cancer?

No. Science has failed to support the theory that colonics prevent colon cancer. 

Diagnosis and Treatment 

Q: If I’m diagnosed with colon or rectal cancer, should I get a second opinion?

Second opinions are always a good idea. 

Q. Is colon or rectal cancer curable?

Absolutely, especially if detected early.

Q: Does it matter which surgeon I go to?

We recommend that patients with colon and rectal cancer have surgery with a surgeon specially trained in cancer or colorectal surgery. 

Q: What are the side effects of chemotherapy and radiation?

For more information on the side effects of these treatments, please see the entries on chemotherapy and radiation therapy in our health library. 

Q. If the cancer has not spread, will I need chemotherapy?

Sometimes. Occasionally patients need chemotherapy either before surgery, to shrink the tumor and make surgery easier, or after surgery, to reduce the risk of relapse. 

Q. When is radiation necessary?

Radiation therapy is an important part of the treatment of rectal cancer but it is usually not needed for the treatment of colon cancer. 


Q: Will I need a colostomy bag after my treatment?

Most of the time, no. Surgery has improved dramatically over the last decade and the need for colostomy bags has been reduced. 

Q: What can I do to prevent a recurrence of cancer?

Continued screening and surveillance, under the direction of your medical oncologist is very important after surgery, radiation or chemotherapy.