Colorectal cancer cases and deaths have been falling for decades, with the most recent decline likely due to screening tests that enable doctors to detect and, if necessary, remove precancerous growths, researchers write in the journal Gastroenterology.
Still, the disease kills more Americans than any other cancer except lung cancer, and half of all Americans over 50 aren’t getting any screening for it, according to the American Cancer Society.
Since Medicare and private insurers began covering screening colonoscopy for average-risk people in 2001, colonoscopy has become the main screening tool. But some recent studies have questioned whether it is any better at reducing cancers in the upper part of the colon than sigmoidoscopy, the scientists write.
Colonoscopy involves inserting a flexible lighted tube tipped with a camera through the entire rectum and colon. Sigmoidoscopy involves inserting a flexible camera-tipped tube through the rectum and only into the lower part of the colon.
The new study analyzed hospitalization data from the largest inpatient care database in the U.S., which includes patients covered by Medicare, Medicaid, and all private insurance companies. It was developed by the federal Agency for Health Care Research and Quality.
Researchers compiled the rates of all hospitalizations for colorectal cancer surgery from 1993 to 2009. Most people diagnosed with the disease undergo at least one operation, called a resection, so the number of resections for colorectal cancer closely reflects the number of cases, the scientists say.
Overall, the colorectal cancer surgery rate, expressed as the number per 100,000 people, dropped from 71.1 in 1993 to 47.3 in 2009. Most of the decline occurred in the latter half of that period, which correlates with the expansion of Medicare and private insurers’ coverage of colonoscopy.
“The curves are very dramatic,” says researcher Uri Ladabaum, MD, associate professor of gastroenterology and hepatology at Stanford University. “Once we got the data and looked at it, we said, ‘Wow, this is really quite a marked change here.’”