What You Need to Know about Colon Cancer

08 January, 2019
People over the age of 50 should have an annual exam to detect colon cancer as early as possible.  A healthy lifestyle is essential in preventing it.

Colorectal cancer, which begins in the lining of the colon and rectum, is an increasingly common disease. For instance, it’s one of the leading causes of death in the United States. However, early diagnosis can lead to a complete cure. Therefore, it’s important to know as much as possible about it for a timely detection.   

What are the causes of colon cancer?

There’s not a single cause for his disease. It can start as a polyp that may become cancerous if left untreated.

People most at risk of developing colon cancer are:

  • The ones that are over 60 years old.
  • African-American or Eastern-Europeans descendants.
  • Who consume a lot of processed or red meats.
  • Those with colorectal polyps.
  • Those with an inflammatory intestinal disease like ulcerative colitis or Crohn’s disease.
  • Patients with a family history (especially if there were cases of familial adenomatous polyposis).
  • Those who eat a diet high in fat with little fiber.
  • Those who smoke or drink in excess.
  • Who are obese or overweight.

Cancer of the large intestine or colon is the second leading cause of death in Spain, and it’s more common in men than women. Only 10% of polyps become cancerous; however, they need to be treated early.

colo-rectal cancer prevention

What are the symptoms of colon cancer?

Symptoms can vary depending on the location of the tumor in the intestine:

  • If located in the left colon: bloody stools, diarrhea and constipation, and feelings of incomplete evacuation.
  • When it’s located in the transverse colon: pain, blockage, cramps, vomiting and abdominal distension.
  • And when it’s located in the right colon: internal bleeding, chronic anemia, fatigue, paleness, and lack of strength.

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In each case, colon cancer can cause loss of appetite, drastic weight loss, fever, chronic fatigue, sensitivity and pain in the lower abdomen, along with thin stools.

How is colon cancer detected?

On one hand, there are medical tests that can determine if a person has colon cancer (or its predecessor: polyps). The doctor applies pressure to the abdominal area in addition to conducting a rectal exam in order to detect lumps in the area.

On the other hand, the stool can also be tested for the presence of blood, which can indicate colon cancer (as well as other diseases).  Other tests check the blood for anemia and liver function.

In addition, also a colonoscopy allows to see the entire intestine and check for cancer or polyps. With this test, a doctor can see the entire intestinal tract and take samples of suspicious tissue for later analysis.

Finally, if injuries don’t allow for a colonoscopy, the silhouette of the colon can be seen on x-rays with a barium enema.

colonoscopy to detect colo-rectal cancer

Stages of colon cancer

If the diagnosis is colon cancer, other tests can determine cancer’s extent and if it has spread. This can be done by using computerized tomography (CT) and magnetic resonance imaging (MRI) in the abdomen and lower stomach.

There are five stages of colon cancer:

  • 0: it’s forming on the outer layers of the intestine
  • I: inner layers of the colon.
  • II: has spread through the colon wall.
  • III: cancer has spread to the lymph nodes.
  • IV: cancer has spread to other organs (metastasis).

Treatment depends on the severity of the disease, for instance, its stage and location. And can include surgery (colectomy) to remove cancerous cells. Likewise, chemotherapy can destroy cancerous cells, and radiation therapy can destroy cancerous tissue.

It’s important to notice that colon cancer is curable if detected and treated early enough.  The prognosis also depends on the age of the patient, as well as the immune system, the stage at which treatment started, etc.

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If five years after treatment have passed and cancer doesn’t reappear, the patient is said to be cured.

Early Diagnosis and Prevention of Colon Cancer

There are many methods available for the early detection of colon cancer; however, in the initial stages, the symptoms can be confused with other diseases.  

Those over 50 are recommended to have their stool tested for signs of blood annually. Certainly, if there’s a family history of cancer, people should take greater precautionary measures. For example, including endoscopy starting at age 40 and repeated every two years. If the results are positive, a colonoscopy can be performed as described earlier.


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Chan, D. S. M., Lau, R., Aune, D., Vieira, R., Greenwood, D. C., Kampman, E., & Norat, T. (2011). Red and processed meat and colorectal cancer incidence: Meta-analysis of prospective studies. PLoS ONE. http://doi.org/10.1371/journal.pone.0020456


Ascherio, A., Stampfer, M. J., Colditz, G. A., & Willett, W. C. (1994). Intake of Fat, Meat, and Fiber in Relation to Risk of Colon Cancer in Men. Cancer Research. http://doi.org/10.1519/JSC.0000000000000496


Majumdar, S. R., Fletcher, R. H., & Evans, A. T. (1999). How does colorectal cancer present? Symptoms, duration, and clues to location. American Journal of Gastroenterology. http://doi.org/10.1111/j.1572-0241.1999.01454.x


Clarke, J. M., & Lockett, T. (2014). Primary prevention of colorectal cancer. Cancer Forum. http://doi.org/10.1053/j.gastro.2010.01.057