What experts wish you knew about colon cancer

While rates of colorectal cancer have declined in recent years among adults aged 65 and older, incidence has risen steadily among younger people, particularly those aged 20 to 64. As a result, colorectal cancer, defined as cancers of the colon or the rectum, is now the leading cause of cancer-related death among adults under age 50. High-profile deaths from the disease — including actors Chadwick Boseman, who died at 43, and James Van Der Beek, who was diagnosed at 48 — have heightened public concern.

Awareness and early testing are critical, experts say. When detected early, colorectal cancer is often highly treatable, and younger patients frequently experience better survival outcomes than older adults.

Yale School of Public Health researchers Caroline Johnson, PhD, associate professor of epidemiology (environmental health sciences), and Sunny Siddique, MPH, PhD, a postdoctoral fellow in chronic disease epidemiology, study the causes and prevention of colorectal cancer. In this interview, they discuss the disease’s shifting demographics, ways to reduce risk, and the screening tools available to detect it early.

Sunny Siddique (SS): I wish more people understood that colorectal cancer isn’t a disease of older age. We have evidence that this disease is increasingly affecting younger individuals.

Caroline Johnson (CJ): A recent study highlights these shifting demographics. Researchers found that in some countries, the incidence of early-onset colorectal cancer (defined as diagnosis before age 50) is similar between men and women. This contrasts with the higher incidence traditionally observed in men among older patients and may suggest a shared cause, or set of causes, among younger individuals.

SS: Colorectal cancer screening is one of the most effective prevention strategies. In addition to implementing a healthier lifestyle — such as reducing sugar and processed foods intake and increasing physical activity — individuals should begin attending recommended screenings at 45. Some people may begin earlier depending on individual risk status. We typically categorize individuals as having either high or average risk of colorectal cancer. Individuals with conditions such as inflammatory bowel disease, a history of abdominal radiation, and family history of colorectal cancer are considered to have high risk.

CJ: However, most cases of colorectal cancer are linked to modifiable environmental risk factors rather than inherited genetic mutations. These modifiable factors include having a sedentary lifestyle, obesity, smoking, and consumption of sugar and sweetened beverages, processed foods, red meat, and heavy alcohol. However, incorporating dietary choices such as high dairy, fiber, and whole grains may help prevent colorectal cancer.

SS: Several types of colorectal cancer screening are currently available for average-risk individuals beginning at age 45. One option is colonoscopy, which is recommended every 10 years. Stool-based screening tests are also available, including the stool DNA test every 3 years, the fecal immunochemical test (FIT) annually, and the fecal occult blood test (FOBT) annually. For all stool-based screening methods, abnormal results should be followed with a colonoscopy. Although there are other screening approaches, such as novel blood-based tests, they are not currently recommended by the U.S. Preventive Services Task Force.

If you think you are at increased risk for colorectal cancer, speak with your doctor about when to begin screening, and which test and frequency is right for you.

If you have symptoms, such as a change in bowel habits, blood in or on your stool, diarrhea, constipation, feeling that the bowel does not empty all the way, abdominal pain, aches, or cramps that don't go away, or unexplained weight loss, talk to your health care provider.