Colorectal cancer

Nearly all colon cancers begin as noncancerous (benign) polyps, which slowly develop into cancer. Colorectal cancer usually starts in the glands of the lining of the colon and rectum, and then progresses to the muscle layers and eventually through the bowel wall. When still confined to the wall, it is often curable with surgery, but once it has spread the cancer is usually not curable. Annually 1.23 million new cases of colorectal cancer are diagnosed worldwide, killing 608,000 people a year.

Symptoms

The symptoms of colorectal cancer depend on the location of the tumour and whether it has spread to other areas in the body. Sometimes there are no symptoms, but the following may indicate the disease:

• • Abdominal pain and tenderness in the lower abdomen

• • Blood in the stool

• • Diarrhoea, constipation, or other changes in bowel habits

• • Narrow stools

• • Loss of appetite and weight loss with no apparent reason

• • Fever

• • Nausea or vomiting

• • Rectal bleeding

• • Anaemia

Causes and risks

The following are considered risk factors that may increase your chance of getting colorectal cancer:

• • Being older than 60

• • Being male

• • Eating a diet that is high in red or processed meats, high in fat content and low in fibre content

• • Having cancer elsewhere in the body

• • Having colorectal polyps

• • Having inflammatory bowel disease (Crohn’s disease or ulcerative colitis)

• • Having a family history of colon cancer

• • Having a personal history of breast cancer

• • Smoking cigarettes

• • Drinking more than one alcohol drink per day

• • Being obese

• • Having a sedentary lifestyle.

In a minority of cases (1% to 3%), genetics may cause colorectal cancer, for example in the case of familial adenomatous polyposis (FAP) and hereditary nonpolyposis colorectal cancer (HNPCC), also known as Lynch syndrome.

Prevention

To prevent colorectal cancer, you can do the following:

Change your lifestyle. Your diet is important. Increase whole grains, fruits and vegetables in your diet and decrease red meat and alcohol consumption. Exercising regularly can reduce the risk moderately. Stop smoking.

Get screened. Screening for colorectal cancer can pick up the disease early on. A sigmoidoscopy every 5 years and a colonoscopy every 10 years are recommended for persons between 50 and 75 years of age. Colorectal cancer screening may detect polyps before they become cancerous and they can then be removed.

Take medication. Although some studies indicate that medications such as aspirin and ibuprofen may help reduce the risk of colorectal cancer, this method of prevention is still controversial as it may increase your risk for bleeding and heart problems.

Treatment

Colorectal cancer is usually diagnosed through sigmoidoscopy or colonoscopy. If the cancer is diagnosed early in the progression of the disease, surgery is done to remove the cancer. Chemotherapy may be prescribed before the surgery to shrink the cancer growth. Chemotherapy may also be used after surgery if the lymph nodes have been affected.

Where the cancer has already spread to other areas of the body, chemotherapy may also be given to shrink the size of the tumour. Radiation therapy may be used for rectal cancer. The aim of other treatments is to improve the quality of life, for example removing some of the cancer tissue through surgery to relieve abdominal pain. The purpose of the treatment at this stage of the disease is directed at extending life and keeping the sufferer comfortable.

How well a person does on treatment, depends on many things, not least the stage of the cancer. When treatment starts at an early stage, many people survive for at least five years after the diagnosis. If the cancer does not come back within five years, it is considered cured.

 

Sources
Healthwise Knowledgebase Inc. Boise, Idaho
www.cancer.gov
www.ncbi.nlm.nih.gov
www.wikipedia.com