Screening may be needed even before age 50…

Most people do not get a colonoscopy until they are 50 years old. That’s the age at which the American Cancer Society and other groups advise patients with average risk to have their first screening for colorectal cancer.

The unloved procedure is the best way to detect and prevent these often lethal cancers, which are second only to lung cancer as the leading cause of cancer deaths in the US. But people who wait until their 50th birthday to get this test might be making a big mistake. Here’s why…


For reasons that aren’t entirely clear, the incidence of colorectal cancers has risen in patients younger than the traditional screening age. Based on the current trend, the number is expected to grow—sharply in some cases—in the coming years.

Should young adults get a first colonoscopy in their 20s, 30s or 40s? For now, doctors will make this decision case-by-case. But the projected increase in cancer cases has led some experts to suggest that earlier screening—along with a more watchful eye for cancer symptoms—could be the most effective way to protect a group of patients that was previously thought to be low risk.


Overall, about 90% of colon cancers will be diagnosed in people who are age 50 or older—but the age of these patients is trending downward.

When researchers from MD Anderson Cancer Center looked at data from more than 393,000 patients who had been diagnosed with colorectal cancers, they found that the increasing risk for younger adults is expected to continue—specifically, within the next 14 years, about one in four rectal cancers and one in 10 colon cancers will be diagnosed in adults under age 50. In people over age 50, incidence of these cancers is declining.


Even though it’s still unclear why colon cancer is increasing in younger adults, possible causes include…  

  • Obesity. It’s become more common for people to be overweight or obese at younger ages. People who are obese or overweight have higher risk for colorectal cancer than those of normal weight.
  • Poor diets. A Western-style diet—high in processed foods, fast food and saturated fat, and low in fiber-rich plant foods—has been linked to higher cancer rates. People born prior to the 1970s tend to have a lower lifetime exposure to processed foods.
  • Lack of physical activity. People who engage in routine exercise are less likely to get colorectal cancer. Exercise also increases survival in those who have already been diagnosed and treated for these cancers. Younger people seem to be less active than previous generations.


The standard guidelines (first colonoscopy at age 50…repeat every 10 years) apply only to people with an “average” risk of developing colorectal cancer. Others (such as those with a parent, sibling or child with colorectal cancer or symptoms including blood in the stool) might be advised by their doctors to have earlier/more frequent tests. My advice…

Understand your risks. I don’t recommend an across-the-board increase in routine colonoscopies. It’s an expensive test with potential complications such as bleeding, perforation of the bowel or a reaction to the sedative used. We have to balance risks and benefits.

Who might need an earlier test: Patients with a strong family history of colorectal cancer (or a family history of precancerous polyps) should ask their doctors if they should be tested before age 50. If a family member was diagnosed at age 50, for example, then screening should begin 10 years earlier—at age 40. Other possible risk factors, such as obesity and/or a lack of exercise, could also warrant earlier testing in some cases.

Note: Highly sensitive fecal DNA tests may be able to identify patients who need colonoscopy before age 50, and virtual colonoscopy (which is noninvasive) is used sometimes for this purpose.

Important: If an older adult has had polyps removed, he/she should tell his children so that they can discuss earlier and/or more frequent colonoscopies with their doctors.

Don’t ignore early symptoms. Young people tend to disregard “minor” bowel problems, such as rectal bleeding (they often blame it on hemorrhoids)…an increase/decrease in bowel movements…or unexplained changes in the consistency of stool. Don’t assume that your age means you cannot get colorectal cancer—take any bowel symptom seriously.

Example: If you’ve noticed rectal bleeding, ask your doctor if you should have an anal exam to rule out hemorrhoids or other causes.

Anemia is another common finding that can indicate colorectal cancer. It is most often identified during routine blood work or testing for symptoms such as fatigue.

If your doctor isn’t convinced that your symptoms aren’t caused by cancer, you should consider colonoscopy.

Eat the right foods. The foods that make up a healthy diet—fruits, vegetables, whole grains, fatty fish, etc.—can also protect against colorectal cancers. Avoid (or limit) processed meats…charred meats (the “char” contains carcinogenic compounds)…sugary soft drinks…and fast food.

It’s particularly important to get more fiber. According to the American Institute for Cancer Research, every 10 g of fiber that you consume daily can reduce the risk for colorectal cancer by 10%. Women age 51 and older need at least 21 g of fiber each day, and men in this age group require at least 30 g daily. There are lots of great sources of fiber—leafy greens, fruits, vegetables, beans, popcorn and wheat germ.

Be smart about exercise. People who exercise are about 40% less likely to get colon cancer than those who are sedentary. Exercise affects insulin regulation, immune activity, inflammation and other factors that influence your risk for colorectal cancer. It also increases motility, the movement of food through the intestine. Increased motility reduces the time that potential carcinogens can affect the intestinal wall.

How much exercise? Any is better than none, although 30 to 60 minutes of moderate-intensity daily exercise—swimming, biking, fast walking, etc.—is ideal.