The implementation of screening colonoscopy could be the primary reason for the decrease in colon cancer rates over the last 10 years, according to a study published in the November issue of Gastroenterology.
A team of researchers from Stanford University School of Medicine using 20 years of data from more than 2 million patients determined that the decline in colon cancer rates corresponded with Medicare's decision in 2001 to reimburse for screening colonoscopy.
Colonoscopy is one of several methods available for colon cancer screening, but, according to Uri Ladabaum, an associate professor of gastroenterology and hepatology and the study's lead author, it's advantage lies in the fact that it can extend beyond the lower colorectum and into the upper or proximal colon.
"The faith for a long time has been that looking more deeply into the colon must be better because we're looking at more of the colon," Ladabaum said in an announcement. Still, the superiority of colonoscopy compared to methods such as sigmoidoscopy continues to be a subject of debate.
The researchers examined data on surgery rates for colorectal cancer using data from the Nationwide Inpatient Sample. The study found that the increasing use of colonoscopy could account for the decreased incidence of upper colon cancer over the last 10 years.
The researchers found that the rate for removing colorectal cancer fell from 71.1 to 47.3 per 100,000 patients between 1993 and 2009. Resection rates for lower colorectal cancer decreased gradually (about 1.2 percent per year) until 1999, and then fell sharply at a rate of 3.8 percent annually from 1999 to 2009. Upper colorectal cancer resection rates were steady through 2002, then dropped at a rate of 3.1 percent afterward.
According to Ladabaum, those results suggest that the lower incidence of lower colorectal cancer could be associated with the adoption of screening methods in general in the 1990s, while the decrease in upper colon cancer incidence could correspond specifically with colonoscopy.