A new study by Douglas Corley, MD, PhD, (pictured) and colleagues shows that stool tests are highly sensitive to finding colorectal cancers, and many eligible KP members are taking the test every year as recommended.
Colorectal cancer is the second-leading cause of cancer death in the United States, yet only two in three adults in the United States is adequately screened.
In California, Kaiser Permanente members between the ages 50 and 75 are screened for colorectal cancer at rates much higher than the national average of 65 percent — more than 80 percent of members are receiving one of three screening tests. The U.S. Preventive Services Task Force recommends that people at average risk be screened with either: (1) an annual stool test, called the fecal immunochemical test or FIT; (2) colonoscopy, which examines the entire colon, every 10 years; or (3) sigmoidoscopy, which examines the lower colon, every five years.
Now a new study of Kaiser Permanente members in California, published recently in the journal Annals of Internal Medicine, shows that the FIT test is highly sensitive for detecting colorectal cancers, and that eligible Kaiser Permanente members are willing to take the test every year as recommended.
Douglas A. Corley, MD, PhD, gastroenterologist at the Kaiser Permanente San Francisco Medical Center and a research scientist at the Kaiser Permanente Division of Research, explains what the study found and why colorectal cancer screening is so important.
How does Kaiser Permanente screen for colorectal cancer?
We offer members options regarding colorectal cancer screening, including the two most commonly used recommended tests: colonoscopy and FIT. Since 2006, we have also annually mailed FIT kits to any member who is not up to date with screening. FIT is a simple test that detects blood in the stool. Blood is an early sign that there may be polyps in the colon, which can develop into cancer. Patients whose FIT results are positive are referred for a colonoscopy.
What did this new study find?
We looked at the results of 670,000 FIT kits that were mailed to eligible members of Kaiser Permanente’s Northern and Southern California regions between 2007 and 2013. More than half of them completed a stool test in the first year.
FIT detected 80.4 percent of patients who were ultimately diagnosed with colorectal cancer in the first year, and 73.4 to 78 percent in the subsequent three years of screening. Furthermore, more than 75 percent of people who started screening with FIT repeated the screening test as recommended. Of those whose FIT tests were positive, almost 80 percent completed the recommended follow up colonoscopy within a year and virtually all had a colonoscopy or other follow-up within one year.
What are the benefits of FIT?
Unlike older stool tests, FIT does not require any dietary or medication restrictions beforehand and can be completed entirely by mail. Furthermore, FIT is done every year, so we can detect cancers that start growing in-between tests with longer screening intervals, such as colonoscopy. This study confirms that members who complete the test every year have excellent long-term outcomes.
I’ve heard that colonoscopy is the best screening test for colorectal cancer. Is that true?
We don’t have evidence that one screening strategy for colorectal cancer is better than another; each has its advantages and disadvantages. The best evidence currently suggests that colonoscopy every 10 years and FIT once a year are similar in terms of the numbers of colorectal cancer deaths prevented. The most important thing is that people get screened by one of the recommended methods. FIT can be done at home, and it doesn’t require bowel preparation or a visit to the doctor’s office. Colonoscopy is also an excellent test, but not everyone is willing to have an invasive test just for screening.