Type 2 Diabetes – Is Colon Cancer More Common in Diabetics?

A study published in the Journal of Korean Medical Science in October 2011 should encourage people diagnosed with Type 2 diabetes to get colonoscopies.

Investigators at Samunsung Medical Center, Sugkyunkwan University School of Medicine in Seoul, Korea, looked at the records of 3,505 Type 2 diabetics who had colonoscopies for colon and rectal cancer from 1995 to 2009 and compared them with the records of 495 non-diabetic patients.

Eleven hundred and thirty-six polyps were recorded among 509 diabetic patients. Of the polyps found in the people with Type 2 diabetes:

  • 8 per cent had the potential for becoming cancerous, compared to
  • 6 per cent in the non-diabetic participants.

Fortunately, the use of metformin or aspirin did not increase the number of polyps seen. Males who were older than 65 years of age with Type 2 diabetes and a body mass index (BMI) of over 25 were at risk for having more than 3 polyps with cancerous potential.

Like all cancers, cancer of the colon is uncontrolled cell growth. Cancers can cause:

  • bleeding,
  • pressure on other tissues,
  • obstruction, and can give off
  • inappropriate hormones and other potentially deadly molecules.

Worldwide cancer caused 13 per cent of deaths in 2008. Colon and rectal cancer was one of the most common, accounting for 610,000 deaths. Deaths from cancer are expected to rise to 11 million worldwide in 2030.

Colon cancer is one of the most preventable cancers. Eating a high fiber diet and regular checkups can prevent its formation. When cancer is present, surgical removal can be curative if done early.

Signs and symptoms of colon cancer include:

  • diarrhea,
  • constipation,
  • feeling of fullness after bowel movements,
  • narrow stools,
  • rectal bleeding,
  • gas pains,
  • bloating,
  • abdominal cramps,
  • weight loss without explanation,
  • tiredness,
  • anemia,
  • nausea, and
  • vomiting.

Colon polyps with the potential for becoming cancerous are called adenomatous. Polyps are removed when they are found and examined under a microscope to discover whether they are adenomatous.

For healthy people, screening colonoscopies are recommended at the age of 50 and every 7 to 10 years thereafter. If an adenomatous polyp is found and removed, the next colonoscopy should be performed in 5 years. If an adenomatous polyp is found and there is a family history of colon cancer, the patient should be rechecked in 3 years. (Colonoscopy can also reveal flat lesions called nonpolypoid colorectal neoplasms, which can also evolve into cancer).

Given the higher risk of adenomatous polyps in people with diabetes, should they be checked more often? Discuss the possibility with your doctor.