Colon Cancer and Rectal Cancer – Is There a Difference?

Colon cancer and rectal cancer are two of the lower gastroenterology cancers. What is the difference between them? What are the risk factors?

Bowel cancer is the general term for cancer that affects the large bowel (colon).

It includes cancers that develop in the colon and rectum (the last part of the colon before the anus). Bowel cancers normally grow very slowly – over a period of up to 10 years – and are treatable if caught early.

About The Colon and Rectum

The colon and rectum are part of the large intestine. The colon is around five feet long. The rectum is the last section of the colon (around six to 12 inches), which joins onto the anus.

The symptoms to look out for that could indicate bowel cancer are listed below. Most people with these symptoms do not have bowel cancer but you should visit your GP to get checked out if these symptoms persist for more than three weeks.

• bleeding from the bottom or blood in your poo
• changes in bowel habit which can include going to the toilet more often, diarrhoea, constipation or a feeling of incomplete emptying of your bowel after going to the toilet
• pain in your abdomen
• unexplained tiredness, dizziness or breathlessness
• unexplained weight loss

Colon and Rectal cancers are sometimes referred to as colorectal cancer, which can be a bit confusing as they are actually different types of cancer.

Colon and Rectal cancers share similar symptoms but there are some very important differences.

Both can produce blood in the poo although there is some difference in colouration.

• Colon cancers tend to produce brown or black blood
• Rectal cancers produce red blood

Colon cancer is common in men and women whereas rectal cancer is far more common in men.

Rectal cancer is more difficult to cure and recurs in 15-45% of patients. Rectal cancer also spreads more easily as it occurs in a more tightly confined area with a greater risk of spreading to surrounding tissues.

Surgery for colon cancer is a more straightforward procedure than rectal cancer surgery because the structure of the rectum makes it more difficult to access the tumour and avoid surrounding structures.

People who undergo rectal cancer surgery have a far greater chance of ending up with a permanent colostomy because the procedure often requires the removal of the anal sphincter, which cannot be reconstructed. There is also a greater risk of post-operative complications with rectal cancer.

The causes and risk factors of colon and rectal cancer are also different.

The risk of both types of cancer is exacerbated by eating red meat but more so in the case of rectal cancer. Colon cancer tends to be associated with alcohol consumption.

Both types of cancer tend to start as benign growths called polyps on the wall of the bowl. These look like cherries on stalks and are very common, particularly as we get older.

A particular type of polyp, called an adenoma, can become cancerous, If undetected the cells in the polyp will multiply to form a tumour in the bowel, causing pain, bleeding and other symptoms.

This tumour can grow into the wall of the bowel, allowing cancerous calls to enter other parts of the body. This process of spread is called metastasis.

Once the type and stage of cancer have been determined, there are a number of different possibilities for treatment: chemotherapy; radiotherapy and surgery. You may be offered one or a combination of all three approaches.

A diagnosis of bowel cancer has major implications for the individual and their family so you will be offered support in managing not only the physical symptoms but also the emotional and practical impacts of the disease.