Deaths from colorectal cancer—the third biggest cancer killer—have dropped 3 percent a year from 2001 to 2010 thanks in large part to an increase in screening among Americans over age 50 and better treatments. Fewer Americans are also getting diagnosed with the cancer these days because colonoscopies can snip out precancerous polyps before they turn malignant.
That good news was reported by American Cancer Society researchers in the cancer journal CA earlier this week, but cancer society leaders and public health officials would like to see even more Americans getting screened for colon cancer. “One in three adults ages 50 to 75 aren’t getting screened as recommended,” said Dr. Howard Koh, assistant secretary for health for the U.S. Department of Health and Human Services, in a press briefing that coincided with the report’s release on Monday. The goal: Get that number to drop to one in five by 2018.
Various medical groups recommend screening for colorectal cancer beginning at age 50 until age 75 using either an annual stool test, flexible sigmoidoscopy every five years, or a colonoscopy every 10 years. The health law now mandates coverage for this screening without any copays—with a few caveats.
“Colonoscopy that’s performed after a positive fecal blood test may not be fully covered,” said Dr. Ronald J. Vender, a digestive disease specialist at Yale Medical Group. And some patients get charged when polyps are removed during a colonoscopy since—oddly enough—the law only mandates full coverage for the screening itself. That’s something Koh and other public health officials are pushing to fix.
Other roadblocks exist for those reluctant to get screened like the dreaded prep for colonoscopy that requires the use of strong laxatives to clear out the colon. Others don’t want to face the tiny but scary risks of anesthesia or perforation of the colon that cause complications less than 1 percent of the time.
I get emails from time to time from readers asking if there’s any screening that would be a good alternative to colonoscopy. I posed this question to Dr. Kimmie Ng, a medical oncologist at Dana-Farber Cancer Institute.
“One test that doesn’t involve doing a prep is the stool test,” she tells me, “but this only detects early cancers, not polyps that haven’t yet turned malignant.” It’s certainly better than skipping screening altogether. What’s more, the at-home tests are getting better at finding tiny malignancies: A new stool test that detects DNA mutations found in cancer cells has a 93 percent cancer detection rate, which is far better than the 74 percent detection rate seen in an older screening test, according to a study published Wednesday in the New England Journal of Medicine.
Another new option for those who aren’t able to undergo colonoscopies for medical reasons: a swallowable imaging capsule, called the PillCam Colon, that snaps images as it travels through the large bowel. It involves the same prep as a colonoscopy and can’t remove any polyps it detects.
The flexible sigmoidoscopy involves a somewhat gentler prep: Patients use an enema instead of laxatives, which clears out the bottom part of their colon. The screening scope, however, only scans the bottom third of the colon so it can miss polyps higher up, Ng said. It also isn’t equipped to excise any polyps, so a colonoscopy may have to be performed anyway.
Virtual colonoscopies using low-dose CT scans to image the colon currently require the same bowel prep as a standard colonoscopy, but that may change in the next few years. Researchers are testing new software that can erase fecal matter from the images to reveal just the colon and any tumors or polyps.