Why you need the test everyone’s talking about

If you’re over 50 and know the answer, give yourself a well-deserved pat on the back (give yourself two pats if you know the answer and you’re younger than 50 but at high risk for this cancer). Colorectal cancer is one of the top three causes of cancer deaths in the United States and Canada, yet it’s one of the most preventable cancers. A huge number of colon-cancer deaths could be prevented if more people caught it early — when tiny growths called polyps are in their precancerous stage. But 50 percent of Americans and 70 percent of Canadians don’t get this important check.

If confusion about the test or just discomfort with the whole idea has kept you from getting one, de-stress and take action! For starters, you don’t always have to have a colonoscopy. Today, you’ve got choices.

Colonoscopy: The gold standard. After a one-evening bowel-cleansing routine at home — yes, you get a free colonic with this — all 5 feet of your colon are checked via endoscope, a flexible tube with a tiny light and camera that spots 90 percent of large polyps and 75 percent of smaller ones. It’s so thorough that rechecks are needed just once every 10 years if results are normal. Another advantage: Docs can remove polyps during the procedure.

Virtual colonoscopy: Just as accurate. New research confirms that this noninvasive alternative catches cancerous and precancerous polyps as well as conventional colonoscopy. It uses a scanner to snap 3-D images of your colon from the outside. Drawbacks? You still need bowel prep, and your colon is pumped full of air for a better picture and, ahem, that gas has to come out afterward. Also, if your doc finds a polyp, you’ll still need a colonoscopy (on an additional day) to remove it.

Sigmoidoscopy: Faster and less expensive than colonoscopy, but less accurate. It checks just the lower portion of the large intestine and rectum. Drawbacks: It missed up to two out of three cancers in one big study. Yup, you still have to go through “bowel prep.” Must be repeated every five years.

Fecal Occult Blood Test. A “wipe and toss” test performed in your own bathroom, it finds hidden blood in your stool — a warning for polyps. Drawbacks: Bleeding could be caused by something else, such as hemorrhoids. If some shows up, you’ll need a colonoscopy to be sure. And it must be done every year. Certain foods (such as red meat) and drugs can throw off the results and must be avoided for days in advance. A newer version, called a fecal immunochemical test (FIT or iFOBT), is more accurate, and you don’t have to change your diet beforehand.

Now that you know what your options are, here’s how to make your test more effective:

Double up. A sigmoidoscopy every five years plus a yearly FIT was 10 percent more accurate than either test alone in a recent study of 21,794 people.

At risk? Start before the big 5-0. If you’re black, you’re at higher risk for colorectal cancer and should start getting colon checks at age 45. If you’ve had colon cancer or have a first-degree relative who had colon cancer or a premalignant colon polyp before age 60, get a colonoscopy every five years starting at 40 or earlier. You also may need earlier testing if you have a chronic inflammatory bowel disease, such as ulcerative colitis or Crohn’s disease.

Prep well. Follow bowel-prep instructions faithfully. (Hey, it’s only for an evening.) Sloppy prep means more missed cancers and undetected polyps.

Go high-def. Yup, the same high-definition video chips and monitors that make your favorite TV shows look so sharp also allowed docs in one new study to spot 20 percent more precancerous polyps during a colonoscopy. If you have a choice, go for it.

Ask for a morning appointment. After a day of bowel prep and a night of fasting, a morning appointment gets you to the lunch table faster. And nobody’s sure why, but early time slots also meant more accurate tests in several studies.

The YOU Docs, Mehmet Oz and Mike Roizen, are authors of “YOU: On a Diet.” To submit questions, visit realage.com.