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Rectal Cancer

Rectal Cancer Overview

The rectum is the lower part of the colon that connects the large bowel to the anus. The rectum's primary function is to store formed stool in preparation for evacuation. Like the colon, the3 layers of the rectal wall are as follows:

  • Mucosa: This layer of the rectal wall lines the inner surface. The mucosa is composed of glands that secrete mucus to help the passage of stool.
  • Muscularis propria: This middle layer of the rectal wall is composed of muscles that help the rectum keep its shape and contract in a coordinated fashion to expel stool.
  • Mesorectum: This fatty tissue surrounds the rectum.

In addition to these 3 layers, another important component of the rectumis the surrounding lymph nodes (also called regional lymph nodes). Lymph nodes are part of the immune system and assist in conducting surveillance for harmful materials (including viruses and bacteria) that may be threatening the body. Lymph nodes surround every organ in the body, including the rectum.

Of the 150,000 cases of colorectal cancer diagnosed each year in the United States, more than 40,000 people are diagnosed with rectal cancer. The most common type of rectal cancer is adenocarcinoma, which is a cancer arising from the mucosa. Cancer cells can also spread from the rectum to the lymph nodes on their way to other parts of the body.

Like colon cancer, the prognosis and treatment of rectal cancer depends on how deeply the cancer has invaded the rectal wall and surrounding lymph nodes. However, although the rectum is part of the colon, the location of the rectum in the pelvis poses additional challenges in treatment when compared with colon cancer.

This article only discusses issues related to rectal adenocarcinoma.

Medically Reviewed by a Doctor on 4/8/2014
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Rectal Cancer »

Approximately 135,000 new cases of colorectal cancer occur in the United States each year, resulting in approximately 55,000 deaths per year.

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