Colon Cancer - Symptoms, Diagnosis and Prevention
Health Education

Colon Cancer - I

Dr.Rakesh Surapaneni profile Authored by Dr.Rakesh Surapaneni on 18 Mar 2013 - 14:14.

Colon cancer is one of the leading causes of cancer. As per GLOBOCAN 2008 there are 20,159 newly diagnosed cases of Cancers in India (1). Review of data from various cancer registries in India shows that there is a gradual increase in the incidence of Colon cancer in India (2).  Even though there are various approved colon cancer screening strategies they are rarely implemented in India. In this article we will address some of the basic information on the symptoms and screening methods for colon cancer as pertaining to Indian population.

What is colon cancer?

Colon cancer is the cancer of the colon. Colon also called the large intestine or large bowel is the last part of the digestive tract and is connected to the anus through the rectum. Even though treated bit differently cancers of the rectum are often included with those of colon and called colorectal cancers or simply colon cancer.

Who is more likely to get Colon Cancer?

Colon cancer can be seen more in people with certain risk factors.  Here we list some of the risk factors for colon cancer (3, 6).

  • If you had a history of colon polyps
  • If there is a history of colon polyps or colon cancer in a close relative
  • History of inflammatory bowel disease such as Crohn’s disease or Ulcerative Colitis (these diseases cause inflammation of the Colon)
  • Some studies have shown higher incidence of colon cancer with obesity and alcohol use.
  • Smoking
  • Male gender

 

 

Early stage colon cancer usually does not cause symptoms and is found when people get screening procedures such as colonoscopy done. Most of the Indians do not get screening for colon cancer present with symptoms.
Some of the common presenting symptoms are:

  • Bleeding with bowel movements
  • Difficulty passing bowel
  • Narrowing of the caliber of the stool
  • Weight loss
  • Jaundice (When cancer goes to the liver)
  • Weakness
  • Anemia (decreased blood as cancer can bleed)

As discussed above people with early stage colon cancer or with pre-cancerous lesions do not have symptoms. There are certain screening tests that can be done in people with no symptoms to identify cancer at an early stage so that they can be treated before they become more advanced.

There are various approved and experimental tests that can be done to screen for colon cancer.Here are some of the tests commonly done:

  • Fecal occult blood testing: Cancer and precancerous polyps can slowly bleed and cause blood to appear in the stool. Your doctor can do a special test on stool sample to identify microscopic blood in your stool that cannot be seen with naked eye, called as fecal occult blood testing. This is the least invasive of all the tests and all you need to do is collect a stool sample at home.
     
  • Flexible sigmoidoscopy: After cleaning the lower part of the bowel with enema, your doctor will directly look at the rectum and the lower third of the colon with a lighted tube with camera (scope) passed through the anus. Doctor will look for any cancer or polyps in this region.
     
  • Colonoscopy: Just like the sigmoidoscopy during a colonoscopy the doctor looks directly inside the colon for any cancer or polyps with a lighted tube (colonoscope). Unlike sigmoidoscopy he will be able to look at your entire colon, not just the lower third. In preparation for colonoscopy you are usually given a preparative solution to drink (laxative) that will cause watery diarrhoea and clear the colon of the stool so it is easier for the doctor to see the inside of the colon. When there are small polyps or cancer found during colonoscopy or sigmoidoscopy they can be biopsied or removed during the procedure.
     
  • Double contrast barium enema: Barium X-ray of your colon looking for cancer or polyps. Not recommended by many societies for screening (6).
     
  • Virtual colonoscopy: Looking at the inside of your colon with CT scan. Considered investigational by many societies (6).

Colon cancer can be seen more in people with certain risk factors. 
Here we list some of the risk factors for colon cancer (3, 6).

  • If you had a history of colon polyps
  • If there is a history of colon polyps or colon cancer in a close relative
  • History of inflammatory bowel disease such as Crohn’s disease or Ulcerative Colitis (these diseases cause inflammation of the Colon)
  • Some studies have shown higher incidence of colon cancer with obesity and alcohol use.
  • Smoking
  • Male gender

The age to start screening and the frequency of screening will depend on your personal risk for colon cancer. As discussed above people with personal history of polyp or strong family history are at higher risk for colon cancer and might need to be screened more often and at younger age. 

Here we list some of the key recommendations from the Asian Pacific Colon cancer recommendations and the United States preventive task recommendations for average risk Patient (6)

  • Screening to start at the age of  50 years.
  • Fecal occult blood testing, flexible sigmoidoscopy and colonoscopy are the preferred screening tests in Asian countries.

If the screening test is negative, consider repeating the screening test in the following intervals:

  • Fecal occult blood testing every year
  • Flexible sigmoidoscopy every 5 years
  • Colonoscopy every 10 years

Please consult your doctor to determine your personal risk of colon cancer and what is the best screening test is for you.

*Disclaimer This is not medical advice. The content is for educational purposes only. Please contact your doctor for any health care issues.