Colon Cancer: Why Is So Much Intestine Removed?

In this post, we discuss the extent of surgery in colon(large intestine) cancer and the principles of colonic resection in oncology.

One of the first things surgeons do after any operation is talk with the patient’s relatives about how the surgery went. After surgery for cancer, a routine practice is to show the part removed (“resected specimen”) if the attendants wish.

A common question I am asked after a colectomy for colon cancer is “Why was such a long part of the intestine removed?”

The extent of colonic resection for cancer depends on

  1. The part of the colon affected by cancer.
  2. The lymph nodes draining that particular part of the colon. (See this article to know more about lymph nodes and their importance in cancer surgery)
  3. The blood vessels which need to be divided (tied off and cut) in order to remove those nodes.

This is a diagram showing the extent of surgery required for colon cancer, based on the principles of lymph node removal, in an article by Dr Suraj Manjunath, surgical oncologist and minimally invasive cancer surgeon

Depending on the location of cancer in the colon, all the lymph nodes that drain that particular part need to be removed. Since the lymph nodes lie along the blood vessels supplying the colon, these blood vessels have to be tied off and cut at their origin in order to remove all the nodes. Once these particular blood vessels are divided, the entire part of the colon which has lost its blood supply must be resected, since it will no longer survive.

Thus even for a small primary tumor, sometimes a significantly long portion of the intestine has to be taken out.

Fortunately, the physiological impact of removing even half the colon is quite small. With time, most people can expect a normal to near normal bowel function. Such is the wonder of the human body!

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