At-home colorectal cancer screening, which involves mailing a stool sample for analysis, is less invasive and more convenient than other screening methods, but they need to be done more often to be effective. A study published in Clinical Gastroenterology and Hepatology found that almost half of patients who completed an at-home test for colorectal cancer failed to repeat the test as recommended. The behavior of primary care providers can increase patient consistency and increase early detection of colorectal cancer.

 

“This isn’t just about a doctor’s recommendation or the individual prevention beliefs of a patient,” said lead study author Ethan Halm, MD, MPH, MBA, who serves as vice chancellor for population health at Rutgers Biomedical and Health Sciences, in a Rutgers University press release. “Systems can have a powerful impact.”

 

Colorectal cancer is the third most common cancer among men and women in the United States, excluding skin cancer, but it is the second most common cause of cancer deaths, according to American Cancer Society. From 2013 to 2022, incidence rates of colorectal cancer dropped by about 1% each year, but this downward trend is primarily among older adults. In people younger than 50, rates increased by 2.9% per year, and among adults ages 50–64, the rate increased by 0.4% per year between 2013 to 2022.

 

Early detection of cancer improves patient outcomes. People older than 45 should begin regular screening for colon cancer in accordance with U.S. Preventive Services Task Force recommendations. Earlier and more frequent colon cancer screening may be necessary for people with inflammatory bowel diseases, such as Crohn’s disease or ulcerative colitis, or genetic syndromes that affect the colon, as well as those with a family history of colon cancer or colorectal polyps, according to the Centers for Disease Control and Prevention. For most people, screening is done every 10 years via colonoscopy, every year with a stool test or every five years through sigmoidoscopy or virtual colonoscopy (CT colonography).

 

Colonoscopy is the gold standard for colorectal cancer screening, and if suspicious-looking areas, or polyps, are detected during a colonoscopy, they can be biopsied. The bowel prep, cost and invasiveness of the procedure can be a drawback. For all other kinds of screening tests, a colonoscopy is required if the test is abnormal. Sigmoidoscopy and CT colonography do not require sedation, but polyps cannot be removed during the procedure. Blood-based tests are also available, but it is unclear how often these tests should be done.

 

The most convenient screening method is a stool-based test, such as the fecal immunochemical test (FIT), because it does not require any bowel prep, is low cost and can be done at-home, but stool tests still have drawbacks. FIT testing is not nearly as sensitive as colonoscopy and needs to be done yearly.

 

“For those doing FIT testing, this is not a one-and-done testing strategy,” said researcher Halm in the press release. “You need to check your rear every year.”

 

The Rutgers University study followed 492,812 adults from four major health systems, including Parkland Health in Dallas and the Kaiser Permanente systems in Northern California, Southern California and Washington state, for a decade after a negative FIT test.

 

In the decade following their negative FIT test, 54% repeated the test six or more times, 30% repeated the test at least once and 16% never tested again.

 

Colorectal cancer was detected in 1,829 adults in the study. Among those diagnosed, the cancer was advanced, meaning it had spread outside the colon or rectum, in 19% of people who never retested, 12% in people who tested at least once more and 12% in people who tested six or more times. Colorectal cancer that had not metastasized or spread was more common among people who tested more than once.

 

People who had seen primary care physicians within the year, those with previous stool-testing experience, and older and healthier patients were more likely to repeat screening. Still, the biggest predictor of retesting was a person’s healthcare system. Kaiser Permanente in Northern California had the highest adherence rates, and they had the best outreach program, mailing FIT kits to patients who were overdue for screening.

 

Overall, the study emphasizes the role of health systems in increasing screening odds by proactively contacting patients and providing tests.

 

“The best test is the test that gets done,” Halm said.