Kaiser Permanente Successfully Screens for Colorectal Cancer


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.

A Kaiser Permanente FIT kit

 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.


Discussion4 Comments

  1. I understand that as a preventative test FIT and colonoscopy are similar. What I’m not seeing addressed is the standard of practice in other regions of the U.S. where the colonoscopy is performed with removal of polyps. If the polyps are removed they can’t turn cancerous, right? Seems that the FIT test, though much easier to do and less invasive, is still waiting to find out if you have cancer.

    • FIT and colonoscopy are equally recommended by national organizations such as the United States Preventative Services Task Force for decreasing the risk of dying from colorectal cancer. Although no completed studies have yet directly compared these two strategies, both have the ability to find precancerous polyps and early cancers. Colonoscopy can find more small precancerous polyps, but also has somewhat greater risks and is less convenient. Thus, many health care groups with high levels of success at screening their members, such as Kaiser Permanente, offer both types of tests, as offering only one type seems to result in a lower likelihood of getting screened.
      Douglas A. Corley, MD, PhD
      Gastroenterologist, San Francisco Medical Center
      Research Scientist III, Kaiser Permanente Division of Research

  2. What is your opinion re annual FIT testing on patients 75 and older with history of adenomatous polyps (3, 2 polyps at first and second) found at two seperate colonoscopies over a 15 year period? Last colonoscopy at age 79.

    • From Douglas A. Corley, MD:
      “Thank you for the inquiry. The standard recommendation for follow-up of adenomatous polyps is using colonoscopy (not FIT). There is not a national consensus regarding at what age to stop performing follow-up examinations for a history of polyps; it is dependent upon the overall health and life expectancy of each patient. We would recommend you discuss this with your doctor.”

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