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6 Expert Tips to Prevent Colorectal Cancer

Cedars-Sinai Cancer Gastroenterologist/Oncologist Offers Prevention Tips, From Screening to Which Foods to Eat—and Avoid

There are no ifs, ands or “butts” about it: March is Colorectal Cancer Awareness Month and a timely reminder to get screened for one of the deadliest—and most preventable—cancers.

Colorectal cancer is the third-leading cause of cancer death for men and women in the U.S. The American Cancer Society estimates that 106,180 cases of colon cancer and 44,850 cases of rectal cancer will be diagnosed in the U.S. in 2022. Colorectal cancer is expected to cause about 52,580 deaths this year. While deaths from the disease in general have gone down over the last decade, due in part to increased screenings, deaths from colorectal cancer among people younger than 55 increased 1% per year from 2008 to 2017.

"When people are healthy, they don't think about preventing illness," said Vi K. Chiu, MD, PhD, director ofVi K. Chiu, MD, PhD Gastrointestinal Oncology and Molecular Presision Programs at Cedars-Sinai The Angeles Clinic and Research Institute.  "But this old adage is still true: An ounce of prevention is worth a pound of cure. We have the tools to prevent this disease.”

Chiu offers these six tips for preventing colorectal cancer:

1.     Get screened for colorectal cancer

Screening can help physicians detect and remove abnormal growths called polyps before they become cancer. When detected early, colorectal cancer is highly treatable, Chiu said. Adults at average risk for colorectal cancer should begin testing at age 45. Those with close immediate family relatives—parents, grandparents and siblings—who have had colorectal cancer should begin screening at age 40, or 10 years before the diagnosis of the youngest first-degree relative. Here are the three main types of screening:

  •  Colonoscopy: “This is the gold standard for detecting precancerous growths,” Chiu said. “I strongly recommend it over other screening options.” During the procedure, the doctor looks at the inside of the colon and rectum with a long, flexible tube that has a light and small video camera on the end. It is inserted through the anus and into the rectum and colon. Suspicious polyps can be removed.
  • Fecal immunochemical test (FIT)-DNA test: Combines checking for hidden blood in the stool—a possible early sign of cancer—and a second test that looks for cancerous DNA in the stool. 
  • FIT-only test: Screens for hidden blood in the stool and detects blood only from the lower intestines. It is performed at home by taking one to three small samples from different bowel movements and sending them to a lab for testing.

2.     Focus on your diet

A number of studies have shown that diets rich in fruits, vegetables and whole grains are linked with a lower risk of colon or rectal cancer, Chiu said. Consume only small amounts of beef, pork and lamb, and eat fewer processed meats, like hot dogs. Eat whole grains, such as oatmeal, brown rice, popcorn and whole-wheat bread.

Also keep tabs on your vitamin D levels, Chiu recommended. Analysis of a large, international study that followed subjects over time found that low levels of vitamin D were associated with a higher risk for getting colorectal cancer.

3.     Exercise

Being active may reduce the risk of colorectal cancer, Chiu said, because it may reduce inflammation in the body. People with inflammatory bowel diseases, such as ulcerative colitis and Crohn’s, are at much higher risk for colon cancer than the general population. “Exercise may decrease gut inflammation and improve immune surveillance to prevent cancer,” Chiu explained.

The U.S. Department of Health and Human Services Physical Activity Guidelines for Americans recommends that adults engage in 2 1/2 to 3 hours of moderate-intensity aerobic activity or an equivalent combination of each intensity each week.

4.     Watch your weight

Being overweight or obese increases the risk of getting colon or rectal cancer because it can alter the function of hormones, such as insulin and leptin, Chiu said. Obese people have higher levels of insulin, which regulates blood sugar and can cause irregular cell growth in the colon.

To maintain a healthy weight, “don’t fixate on specific foods, but in general, eat lots of fish, vegetables and the other healthy foods we’ve been taught about,” Chiu said. “Basically, decrease your intake of sugar, fats and salty foods.”

5.     Limit alcohol

“Alcohol can cause intestinal damage. It is a toxin whose byproduct can damage DNA,” Chiu said. “The gut may develop inflammation, and the gut immunity is weakened. This can lead to colorectal cancer development.” Limit alcohol consumption to no more than one drink per day.

6.     Do not smoke

Smoking increases the risk for colorectal cancer, Chiu said, because it causes DNA damage and inflammation in the intestine and lung. That can cause hypoxia, a condition in which there is insufficient oxygen at the tissue level, which in addition to DNA mutations, may cause aberrant cells to develop in the body and transform into cancer.

A 2020 German population study of more than 4,900 participants, published in the British Journal of Cancer, found that current smoking was associated with a 59% higher risk of colorectal cancer, and former smoking was associated with a 19% increased risk. The risk was not increased among those who stopped smoking more than 20 years prior.


Read a firsthand story about metastatic colon cancer on the Cedars-Sinai Blog: Staying in the Fight: Bobby Clark's Cancer Story