If you’re over the age of 50, you probably already know that it’s time to begin getting regular screenings for colorectal cancer, but the effectiveness of colonoscopy cannot be overstressed. In a new study, this highly-recommended diagnostic procedure was shown to reduce overall risk of late-stage colon cancer by 70 percent.
The Study
Performed by researchers at the University of Pennsylvania, the study involved over 1,000 adults between the ages of 55 and 85 who were at an average risk of developing colon cancer.
On top of a 70 percent overall risk reduction, researchers found that colonoscopy screening led to:
- 74 percent risk reduction for left-sided colon cancer
- 64 percent risk reduction for right-sided colon cancer
This second point is of particular interest. Some have expressed doubts about colonoscopy’s ability to detect right-sided colon cancer, which accounts for approximately 50 percent of new cases in the US each year. The issue may stem from the comparative difficulty of reaching the right side of the colon (“ascending colon”), which is further from the anus than the left side (“descending colon”). Polyps on the right side may also be flatter than those found on the left, making them more difficult to locate and excise.
However, this study may largely assuage those doubts and demonstrate colonoscopy’s effectiveness in detecting cancer on both sides of the colon. As a frame of reference, those screened with sigmoidoscopy in the study experienced a 50 percent overall risk reduction, a 64 percent reduction in left-sided risk and a 21 percent reduction in right-sided risk. For 251 of the study participants who were diagnosed with right-sided late stage colon cancer, the disease would not have been found with sigmoidoscopy.
Studies like these highlight the importance of getting colonoscopies at the intervals recommended by your colorectal specialist. From the age of 50 on, colonoscopies are recommended once every five to 10 years, while those at higher risk due to family history or factors like inflammatory bowel disease (IBD) may need to begin screening earlier and at different intervals. Though the American Cancer Society has estimated that 50,830 people will die of colorectal cancer in 2013, many of these deaths may be preventable with proper diagnostic procedures and early detection.
