How Likely Is it for Colon Cancer & Rectal Cancer to Occur Together?

Many people assume that colon cancer and rectal cancer are the same thing or that they have a cause-and-effect relationship. However, while these two distinct conditions have many similarities, including their symptoms, they also have several key differences.

Differences between colon cancer and rectal cancer

The first differentiating factor between colon cancer and rectal cancer is the area of the body in which the conditions originate. Both the colon and rectum are parts of the large intestine. However, the colon consists of the first several feet of the large intestine, while the rectum consists of the last few inches where the large intestine attaches to the anus.

Other differences between colon cancer and rectal cancer include:

  • Prevention strategies – There are several screening tests available that can potentially detect colon and rectal cancers in early stages, when they are generally more treatable. Depending on a patient’s risk factors, symptoms and other considerations, a physician can recommend the most appropriate screening strategy, which many include a colonoscopy, sigmoidoscopy, CT colonography, stool test or fecal occult blood test.
  • Potential for tumor spread – In comparison to the colon, the rectum is much shorter in length, and it is also situated in a much tighter spot within the pelvic region. For these reasons, rectal cancer can be more challenging to treat and therefore is more likely to spread than colon cancer.
  • Treatment options – Both colon and rectal cancer can be treated with surgery and/or chemotherapy. While radiation therapy may also be recommended for treating rectal cancer, this approach is not commonly used to address colon cancer.

If left untreated, colon cancer can potentially spread throughout the large intestine and to other areas of the body. This also holds true for rectal cancer. When the two conditions occur – either separately or together – they are often referred to as colorectal cancer.

If you’d like to learn more about cancers that affect the colon and rectum, you can request an appointment with an oncologist in the Gastrointestinal Oncology Program at Moffitt Cancer Center. Call 1-888-663-3488 or complete our new patient registration form online. We do not require referrals.