What is Colon?

To know about colon cancer, we have to know first about colon. Colon is the last portion of the digestive system in human beings. It comprises the upper 4 to 5 feet of the large intestine, and the rectum makes up the lower 6 inches. It is a muscular tube which extracts water and nutrients from solid waste. It is the place that deals with the waste and toxic material before they are expelled from the body through rectum and anus. The colon consists of the ascending colon, transverse colon, descending colon and the sigmoid colon.

What is Cancer?

A cell is the basic structural and functional unit of the body. It is the smallest unit of the body classified as ‘living’ and is called the building brick of the body. Cells generally divide to replace old, ageing cells and they divide only as per requirement of the body when the body needs them. Cancer occurs at the cellular level when cells start dividing and producing new cells without the body needing them.

Benign and Malignant Tumours

Sometimes the cells divide without any control or order and produce a mass of tissue called a tumour or growth. This tumour could be benign or malignant. Benign tumours are not harmful. They can be removed by surgery and generally do not come back. More importantly they do not affect the nearby cells or tissues. The cells of benign tumour do not spread to other parts of the body. Cancer cells can break away from the tumour and enter the blood stream or lymphatic system. Malignant tumours are dangerous and life threatening. They can be removed, but they can come back. They invade and damage the nearby tissues and their cells can break away and enter the blood or the lymphatic system. Cancer cells can form new tumours and damage other tissues and organs. Benign tumors of the large intestine are called polyps, malignant tumors are called cancers. Both are growths arising out of the inner wall of the large intestine.

Colon Cancer

It is cancer of the large intestine (colon), the lower part of the digestive system. Rectal cancer is cancer of the last 6 inches of the colon. Together, they're often referred to as colorectal cancers, large bowel cancers or simply colon cancers. Most of the cancers of the large intestine are thought to be developed from polyps. A colorectal polyp is a fleshy growth (polyp) occurring on the lining of the colon or rectum. Untreated colorectal polyps can develop into colorectal cancer. Because newer and better techniques are being developed in screening, the polyps are detected early which lead to their removal resulting in lesser cause of death due to colorectal cancer over the years. Lesser incidence of deaths is also due to better treatment methods and medicines now available. When the cancer of colon spreads outside the colon, the cancerous cells get deposited in the nearby lymph nodes. From there, they spread to other lymph nodes and organs. Colorectal cancer cells most often spread to the liver. The spread of this disease to distant organs is called metastasis. Once metastasis has occurred in colorectal cancer, a complete cure of the cancer is unlikely.

The incidence of this disease is higher in the Western world and less in Asia and Africa. Globally, cancer of the colon and rectum is the third leading cause of cancer in males and the fourth leading cause of cancer in females. It is estimated that 655,000 deaths occur due to colorectal cancer worldwide per year and it is the second leading cause of cancer-related death in the Western world. Around 108,070 new cases of colon cancer-53,760 in men and 54,310 in women)-and 40,740 new cases of rectal cancer -23,490 in men and 17,250 in women- have been diagnosed in the United States alone in 2008. The risk of developing cancer of the colon is higher in men than in women.

Risk Factors

The risk factors- those factors which affect one’schances of getting a disease-of colorectal cancer are many. It is not necessary for a person to get colorectal cancer even if he carries one or many risk factors. Similarly a person need not have any risk factor in him to get the disease.

Unchangeable Factors

Generally persons over the age of fifty are in the high risk group with over 90% of the people diagnosed with colon cancers above the age of fifty. A person with a history of Inflammatory Bowel Disease, a condition where the colon is inflamed over a long period of time has a higher risk of getting colon cancer. People with a history of colorectal cancer or adenomatous polyps- the polyps that become cancerous -in one or more first-degree relatives (parents, siblings and children) are at an increased risk. The risk becomes double in those with a single affected first-degree relative, and is even higher in people with a stronger family history like in case of a history of colorectal cancer or adenomatous polyps in any first-degree relative (parent, sibling, or child) younger than age 60 and in case of a history of colorectal cancer or adenomatous polyps in 2 or more first-degree relatives at any age. Inherited genes, shared environmental factors, or some combination of these could be the reason for this cancer running in the family. About 5% of people who develop colorectal cancer have an inherited genetic susceptibility to the disease. The 2 most common inherited syndromes linked with colorectal cancers are familial adenomatous polyposis (FAP) and hereditary non-polyposis colorectal cancer (HNPCC). FAP is caused by mutations in the APC gene that a person inherits from his or her parents. About 1% of all colorectal cancers are due to FAP. HNPCC can be caused by inherited changes in a number of different genes that normally help repair DNA damage. The lifetime risk of colorectal cancer in people with this condition may be as high as 70% to 80%. People with a rare inherited condition called Peutz-Jeghers syndrome where they tend to have freckles around the mouth, and sometimes on the hands and feet, and large polyps in their digestive tracts are at a larger risk of getting colorectal cancer. Racial and ethnic factors are also found to play a part in this disese. For example East European Jews have one of the highest rates of cancer of colon.

Life Style Related Factors

People who drink heavily or use tobacco for a long term or those who are physically inactive and those who are obese have a higher risk of getting cancer of colon. High red meat diet like beef, lamb, liver etc. and deep fried meats can induce colorectal cancer. Vegetarians are at less risk of getting this dreaded disease.

Signs and Symptoms

Generally people with colon cancer do not feel any early symptoms. When the symptoms do appear, they may be varied depending on the size and location of the cancer in the large intestine. Blood in the stool, a feeling that the bowel is not emptying completely, constant pain in the abdomen, cramps, gas, pain, abdominal discomfort, fatigue, weight loss and a change in bowel habits with diarrhea or constipation, and a change in the consistency of the stool for more than two weeks are the most prominent signs of this type of cancer.

Warning Signs

Blood in the stool and a history of colon cancer in the family are two signs one has to keep an eye on especially as one advances in age. Also, if one has to be alert if he has a hard time using the bathroom. The symptoms and warning signs easily get mixed up with other diseases and problems and one is advised to consult a doctor if he suspects he has colon cancer.

Causes

The exact causes which induce this cancer are not known, so it is better for one to be aware of the risk factors which promote colon cancer.

Reducing the Risk

Keeping the colon clean by using a colon irrigation equipment from time to time or pills reduces the risk of colon cancer. Also, eating the right kind of food and drinking plenty of water can reduce the risk though they are by no means a fool proof method to prevent colorectal cancer.

Treatment

Surgery, either cutting open or through the anus is the most effective and common treatment of colon cancer. This could be followed by chemotherapy. Alternative treatments are being examined, but their efficacy is not known.