Kaiser Studies Show Value of Colon Cancer Screening

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The death rate from colorectal cancer, the second most common cause of cancer deaths in the U.S., has been cut in half by a regular screening program in the Northern California division of Kaiser Permanente, the big health maintenance organization.

Kaiser organized what it calls an integrated program more than a decade ago, and by 2011 was screening more than 80 percent of eligible adults aged 50-75.

While there has been a decline in colorectal cancer death rates everywhere in the U.S., the decline among Kaiser’s patient population was an impressive 52 percent from 2000 to 2015.

As reported in Gastroenterology, the leading medical journal in the field, the decline was from 31 to 15 deaths per 100,000 population.

In addition, the rate of discovering new colorectal cancer cases declined by 26 percent, apparently because the screening program was detecting and allowing the safe removal of polyps, the small intestinal growths that can be cancer precursors.

Kaiser achieved its screening results well ahead of a goal set by the National Colorectal Cancer Round Table, an initiative of the American Cancer Society and the U.S. Centers for Disease Control and Prevention.

That goal was to achieve 80 percent screening nationwide by 2018. Kaiser and the Veterans Administration are unusual in having reached the goal already. While nationwide screening rates are inching upward, they have reached 67 percent only in the past year.

Kaiser Permanente also reported a related finding late last year, a large study that demonstrated that after a healthy colonoscopy, 10 years is a medically defensible interval to wait before having another colonoscopy.

The findings were reported in another leading medical journal, JAMA Internal Medicine. The 10-year guideline was already widely followed, but this was thought to be the first large study to demonstrate its validity.

Study leader Jeffrey Lee, a Kaiser Permanente gastroenterologist and research scientist in Kaiser’s Division of Research, said it is now clear that “there is a reduced risk of developing and dying from colorectal cancer for at least 10 years” following a colonoscopy that reveals no cancer or polyps.

Second Leading Cancer Killer

Causing just over 50,000 deaths per year, colorectal cancer is the nation’s second-leading cancer killer. (Lung cancer is the leading killer at about 154,000 deaths per year.)

About 140,000 new colorectal cancers are diagnosed every year in the U.S. If screening catches them early, before they spread, 90 percent can be treated successfully.

Colonoscopies are the most effective screening test, but they are also time-consuming, expensive and carry a roughly one-in-a-thousand risk of serious complications for the patient.

For those reasons alone, gastroenterologists generally prefer to conduct colonoscopies only once or twice during the peak window of colorectal cancer risk, age 50-75. In addition, of course, patients find them unpleasant and may resist scheduling them.

Fortunately, a simple, noninvasive test that can be performed at home and mailed in – the fecal immunochemical test, or FIT – gives a reliable indication of whether a full colonoscopy is or is not needed.

“We have found that Kaiser Permanente members are more than willing to be screened with the FIT kit, which has greatly contributed to our high screening rates,” said Theodore Levin, another Kaiser gastroenterologist in the Division of Research, as well as a lead author of the Gastroenterology article.

Kaiser made the FIT tests available, used automated reminder systems for scheduling their use and soon was processing more than 3,000 tests per days in its laboratories, according to an internal newsletter.

Earlier Cancers

For unknown reasons, colorectal cancers among younger people have been increasing at a rate of one or two percent per year, so the American Cancer Society now recommends starting FIT screening at age 45.

Not everyone agrees. The U.S. Preventive Services Task Force continues to recommend that screening start at 50, assuming a patient is thought to be at average risk.

Higher risk patients are typically those whose parents or siblings had colorectal cancer, especially at an early age, and those with specific symptoms, like irritable bowel syndrome or blood in the stool.

They should discuss early screening with their primary medical care provider, Kaiser advises.

Screening at age 45 is generally recommended for African-Americans, who have significantly higher rates of early colorectal cancer than any other population.

As with many kinds of medical examination, doctors look for a balance between a procedure’s medical value and its costs and risks.

Absent a specific sign of higher risk, colonoscopies are “a relatively big deal” and not recommended until someone enters the peak colorectal cancer window of age 50-75, said Levin, the Kaiser gastroenterologist.

For those who do choose to begin screening earlier, “I would lean toward using something non-invasive like a FIT test…a really good option for people at average risk.”

If a FIT test has positive results, meaning it reveals intestinal bleeding, gastroenterologists can move on to a colonoscopy.

Levin said that he and colleagues at Kaiser had compared the results of two basic programs for people of average risk. One is conducting a colonoscopy every 10 years starting at age 50, the other annual FIT tests starting at age 50 with a single colonoscopy about age 65.

The two approaches were equally effective at protecting health. At age 54 and of average risk, Levin himself has decided to follow the second approach: annual FIT exams leading to a colonoscopy at age 65.

Prevention

As for prevention, Levin said that lifestyle choices that reduce the likelihood of heart disease also reduce the likelihood of colorectal cancer.

These include avoiding smoking, regular exercise, weight control and eating less meat and more plant-based foods.

“So much of colon cancer is really the interaction between the genes you inherit and the environment, and by environment I also mean…your diet, how much exercise do you get, how much extra weight are you carrying around, how much alcohol do you drink, are you smoking.

“These are all things that interact with your propensity to form polyps, whatever genetic makeup you might have. So if you are living a healthy lifestyle – the same lifestyle that would decrease your risk of heart disease, that would also decrease your risk of polyps and cancer.”