Metastatic cancer of the colon is the world’s third leading cause of cancer in males (after skin, prostate and lung cancer) and the fourth leading cause of cancer in females (following skin, lung and breast cancer).  An estimated 146,940 new cases of colon cancer are diagnosed every year, and more than fifty thousand deaths occur each year due to this disease.

What is metastatic colon cancer?

Metastatic colon cancer is a cancer that has spread from its primary site in the colon (the part of the digestive system where waste material is stored) to other parts of the body.

How does metastasis occur?

Cells from a cancerous tumor in the colon break away and find their way to the bloodstream, where they get transported to other parts of the body.  Some cancerous cells may also spread through the lymph system, which consists of lymph vessels (veins that contain tissue waste products and immune system cells) and lymph nodes (bean-shaped collections of immune system cells that help fight infection).

How does metastasis affect a colon cancer patient’s chances of survival?

People who die of colon cancer usually suffer from metastasis at the time of their death.  Usually, many cases of colon cancers can be cured by surgically removing the part of the colon where the cancerous tumor has grown.  The serious consequences occur when the cancer has spread to other organs of the body, like the liver, lungs or brain.  In some cases, the body’s normal metabolism is disrupted because the cancer has spread and grown in so many body organs.

Is recurrence and metastasis the same?

No.  Recurrence refers to a cancer that comes back to a patient who had been declared free of cancer after treatment.  Cancer usually recurs locally, or in the same organ where it originated, as in the colon.  In other cases, the recurrence is regional, or happens in lymph nodes found near the original cancerous area.  Distant recurrence also occurs, when the cancer reappears in other parts of the body such as the bones, the liver, or the lungs.  Cancer, then, can recur without metastasizing, and can metastasize without local recurrence.

If the cancer has spread, how do doctors know where it actually started?

Examinations or x-rays may reveal where the cancer actually started.  Its appearance under the microscope can also sometimes tell doctors of its area of origin.  In some cases, however, the cancer does not show any microscopic clues and it becomes impossible to identify where it started.

Why do cancers spread?

Sadly, the exact reason for the spread of cancer is not yet known.

What are the symptoms of metastatic colon cancer?

Many patients do not exhibit any symptom of metastatic colon cancer until it has spread to other parts of the body.  However, some do show symptoms like fatigue, anemia, altered bowel movement, weight loss, night sweats, pain in the right shoulder and blood in the stool, which is the most serious symptom of colon cancer.

What are the causes of metastatic colon cancer?

There is no exact known cause of metastatic colon cancer, or any cancer for that matter.  However, there are risk factors which include the following:

Genetic or hereditary factors: A person with a history of colon cancer running in his family is two to four times more likely to develop cancer himself.  The greater the number of close relatives who have or had colon cancer, the greater is the risk.

Age:  Ninety percent of metastatic colon cancer occur after the age of fifty.  The average age of colon cancer patients is 60.

Occurrence of polyps:  Polyps are growths on the inner wall of the colon, which may either be non-cancerous (benign) or cancerous (malignant).  Polyps are common in people over the age of fifty.  To reduce the risk of cancer, polyps in the colon should be removed through surgery.

Race:  People of the black race are more likely to get colon cancer (48.7 percent per 100,000 incidence in the U.S.), followed by whites (39.3%), Hispanics (26.5%), Asians and Pacific Islanders (32%) and Native Americans/Alaskan Natives (26%).

Diet:  Studies have shown that people who eat food high in fats and low in calcium, folate and fiber are at more risk to develop cancer.  Similarly, people who eat less fruits and vegetables have a higher risk of metastatic colon cancer.

Cigarette smoking:  Smokers are at a higher risk of developing polyps, which in turn may develop into cancerous tumors.

What is the best way to prevent metastatic colon cancer?

The most effective way to prevent colon cancer is early detection.  There are diagnostic tests that can be done to examine the colon and tell whether a person has colon cancer, like barium enema (a patient is subjected to x-ray after being administered an enema of liquid with barium); colonoscopy (a procedure where a doctor inserts a long, flexible viewing tube into the rectum); and blood tests (to detect the presence of carcinoembyonic antigen or CEA, a substance produced by some cancer cells).

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