Unlike some unnecessary medical screenings, colonoscopies and other tests for colon and rectal cancer are highly effective. They really do save lives. Everyone should get screened by age 50—sooner if you have a genetic predisposition to colorectal cancer or a condition such as inflammatory bowel disease.

But there’s been controversy over how long screenings continue to make sense as you get older. After all, colon and rectal cancers are slow-growing, so at a certain age, you’re much more likely to die from something else, such as heart disease, than from colon cancer. Eventually the risks of colonoscopy, albeit small—such as complications of anesthesia—might outweigh the benefits. Is that age 70? 75? 85? 100?

To find out, the United States Preventive Services Task Force (USPSTF), which sets guidelines for American medicine, did a thorough review of the medical literature on the topic.

Bottom line: Keep doing your preps, folks. The findings…

  • There is a “high certainty” that colorectal screening up to and including age 75 provides substantial net benefit. Advice: Get it done.
  • Even after age 75, up to age 85, there is still a moderate benefit. Advice: Make your own decision, with your doctor, based on your overall health and previous screening history.
  • After age 85, any benefit of screening is, at most, very small, and outweighed by the risks. Advice: No screening in almost all cases.
  • Exception: If you’ve never been screened, get screened—whatever your age.

GETTING SCREENED THE RIGHT WAY

Colonoscopy is the only screening method that can actually remove growths—polyps—and get them tested to see if they are precancerous. It actually gets rid of the cancer threat. If all is clear, it’s repeated every 10 years. If a precancerous polyp was removed, it’s repeated more frequently.

But it’s not the only approved method…

  • Stool-based tests, which don’t require bowel cleansing (prep) or sedation, include a fecal occult blood test, as well as the more advanced stool DNA tests, which look not only for blood but for altered DNA biomarkers.
  • Computed tomography (CT) or “virtual” colonoscopy provides an image of the colon using radiation but no sedation. It’s repeated every five years.
  • Flexible sigmoidoscopy, which shows growths in about one-third of the colon. It’s also repeated every five years.

If you have a stool test, a CT scan or a sigmoidoscopy and it finds a potentially precancerous polyp, you’ll still need a colonoscopy to remove it. While the USPSTF didn’t take a stand on which screening method is best, every health expert in the field agrees—any screening is better than no screening. If you choose a colonoscopy, make sure you get it done right…

  • Have your colonoscopy done by a trained gastroenterologist rather than, say, your primary care doctor.
  • Prep smart. How well you prepare your bowel before the colonoscopy can make the difference in how effective it is in picking up—and removing—cancer threats.
  • Even though screening makes sense well into older ages, nearly one-quarter (23%) of colonoscopies may still be unnecessary—ordered too frequently, for example.
  • Even if you’ve had a precancerous polyp removed, you may not need to repeat a colonoscopy as often as you thought.

Colon cancer screenings aren’t exactly a fun topic. But it’s a tragedy that colon cancer still kills nearly 50,000 Americans a year. After all, if every person got a colonoscopy by age 50, about two-thirds of the cases of colon cancer would never have developed.