Bowel cancer

Note: The information on cancer types on the ACRF website is not designed to provide medical or professional advice and is for information only. If you have any health problems or questions please consult your doctor.

Overview

Bowel cancer (also called Colon or Colorectal Cancer) occurs in the colon or the rectum. The colon, a muscular tube around 1.5 metres long, absorbs water and nutrients from food. It is divided into four sections – the ascending colon, transverse colon, descending colon, and sigmoid colon. The rectum, which is the lowest six inches of the bowel, is the holding place for stool, which eventually passes out of the body through the anus.

Most bowel cancers appear to grow in the sigmoid colon – the part just above the rectum. Bowel cancer often begins with the development of small benign growths called polyps, which have a mushroom-like appearance. Polyps can become malignant and lead to the spread of cancer through some or all of the tissue layers making up the colon and rectum, often over several years. The stage the disease reaches is determined by how many of the tissue layers the cancer penetrates.

Around 95 per cent of bowel cancers are adenocarcinomas, which are cancers of the cells lining the colon or rectum’s interior. Other rarer tumours include carcinoid tumors, gastrointestinal stromal tumors, and lymphomas.

Bowel cancer treatment

Treatment depends on the size of the tumour, how deeply the cancer has penetrated the layers of the colon or rectum and whether it has spread to other organs, including the liver or lymph nodes. If the cancer is limited to a polyp, a surgical procedure called a colonoscopy to remove it could cure the disease.

Occasionally, the cancer is limited to a portion of a polyp and many patients in this situation are cured by polyp removal, commonly during a colonoscopy.

If the cancer has spread to the colon, a surgeon may remove a portion of the bowel in a hemi-colectomy procedure, along with nearby lymph nodes, if the cancer has spread. Laparoscopic technology and fiber optics advances mean surgeons can often perform the procedures using small incisions.

If the cancer is in the rectum, surgery can be more complex. Just as a lumpectomy for breast cancer removes as little of the healthy breast tissue as possible, if small cancers in the rectum haven’t grown through the bowel wall they may be removed locally. If the cancer has grown through the rectum wall or spread to lymph nodes, more extensive surgery could be required.

Radiotherapy, which uses x-rays to kill or injure cancer cells so they cannot multiply and chemotherapy, which uses drugs to kill or slow their growth, are often combined to make treatment of this disease more effective.

New treatment approaches include preparative chemoradiation therapy prior to surgery and the delivery of chemotherapy, if the cancer has spread to the liver, using an intrahepatic pump.

Further details on Bowel Cancer are available on Bowel Cancer Australia website.