The American Cancer Society (ACS) recently released new guidelines regarding colorectal cancer screening for the average-risk individual. The big news is that they now recommend that screening for colorectal cancer begin at age 45 rather than age 50. This reduction in the starting age was in reaction to recent data showing that colon cancer is increasing in younger Americans for unclear reasons. By screening people at a younger age, the hope is that we can detect and prevent colon cancer in more people.
The ACS states that 20 percent of new cases of colorectal cancer occur in the younger-than-55 crowd. Furthermore, despite a general downward trend in colorectal cancer in the over-50 population, the risk is actually rising slightly in the subgroup of people aged 50 to 54. These are the cases of cancer the new guidelines are trying to prevent. The ACS is pragmatic in acknowledging that people don’t typically sign up for a colonoscopy exactly on their fiftieth birthday; in fact many wait a few years or more after age 50 to get screened. By pushing the starting age up by five years there will likely be a benefit to these patients who would otherwise be late to the colonoscopy party.
The consequences of these recommendations are potentially huge. If these guidelines are followed, an estimated twenty million additional people are now eligible for colon cancer screening. However, the ACS does not specify any one best choice for colorectal cancer screening and states that colonoscopy, stool DNA testing (Cologuard), virtual colonoscopy, and stool testing for occult blood with Guaiac-based tests or FIT testing are all equivalent. I think that by now we know that all tests are not really equivalent, with colonoscopy being the gold-standard test, but with millions of people not getting any type of screening at all, any test is better than nothing.
A few caveats about these new recommendations:
The ACS states that the recommendation to start screening at age 45 is a qualified recommendation, meaning that there are clear benefits of screening at this younger age but there is less certainty about the exact risk-to-benefit ratio of the recommendation. This is opposed to a strong recommendation, which means the benefit is clear and almost everyone should do it. (Beginning screening at age 50 remains a strong recommendation from the ACS.)
Other guideline-producing organizations such as the U.S. Preventive Services Task Force (USPSTF) have not changed their recommendations for colorectal screening, which still remain at age 50 to start.
Just because the American Cancer Society changed the recommendation to age 45, doesn’t mean that insurance companies are going to cover the testing. This is perhaps the most interesting part of these new guidelines: Who is going to pay for this?
Starting screening earlier is definitely going to pick up and prevent more cancers than starting later, however, is 45 the best age to start? Surely starting at 44 would pick up even more cancers. I bet starting at 40 would pick up even more than that! What I’m trying to illustrate is how there can be a slippery-slope with these type of recommendations: You will always find more cases of colorectal cancer if you start looking for it in younger and younger people. At what point do the risks of screening more and more people start to outweigh the benefits? Only time and more research will help answer this question.
What about the truly early-onset colorectal cancer patients? These are patients diagnosed in their twenties and thirties: How do we detect them before they develop the disease? I doubt anyone will recommend starting routine screening colonoscopies at age 18. This very young-onset colorectal cancer may just behave differently than the typical sporadic colon cancer that develops later in life. We need to develop different ways of finding the young patients at risk, and determine why the risk is rising in the younger population.
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