Cancer society recommends earlier colon, rectal screenings
The American Cancer Society on Wednesday recommended individuals start colorectal cancer screenings at age 45 rather than 50 based on new evidence that more younger and middle-aged adults are developing the diseases.
The update marks the first full change to the society's guidelines since 2009, and it's the earliest age recommended by major American medical societies and organizations. The U.S. Preventive Services Task Force and the American College of Physicians recommend adults at average risk for colon and rectal cancer start testing at age 50 and continue through the age of 75.
The change in recommendations came on the same day the American Cancer Society's medical journal CA: A Cancer Journal for Clinicians published a study that found colorectal cancer incidence rates among adults under 50 rose by 51% since 1994. Rates among adults ages 55 and older have declined steadily during the same period.
A February 2017 analysis published in the Journal of the National Cancer Institute found that adults born around 1990 had twice the risk of colon cancer and four times the risk of rectal cancer compared with adults born around 1950, who have the lowest risk. Adults under age 55 now make up nearly one-third of all rectal cancer cases, according to the study.
Colorectal cancer death rates among adults under 50 have also risen over the past two decades. Mortality rates for colorectal cancer in adults ages 20 to 54 increased by 1% each year from 2004 to 2014, according to an August 2017 study published in the Journal of the American Medical Association.
Dr. Richard Wender, chief cancer control officer for the American Cancer Society, said it was not entirely clear why the risk age for colorectal cancer has shifted to younger adults. He theorized that the cause was environmental rather than a genetic change because of how fast the trend has occurred.
"There may be something in the food that we're eating or how we're living that we have not yet identified that's explaining this change," Wender said.
Wender said the change in the recommended starting age for colorectal cancer screening was initially borne out of discussions over whether the society should recommend that black adults get screened under age 50 based on their high incidence rate at younger ages compared to other racial and ethnic groups.
But a review of current data showed the historic racial disparities in colorectal cancer rates between black and white adults had narrowed. Cases of colorectal cancer among younger white adults had sharply increased within the past decade while rates among black adults remained steady over that same time.
"Most of this increase in risk among younger people has been in the white population," Wenders said. "What we're observing is that that white-black difference that was observed 25 years ago is largely gone and the risk is virtually the same in white and black people."
Most other groups that issue similar guidelines have yet to respond to the ACS' changes. The American College of Physicians, which recommends beginning colorectal cancer screening at age 50, declined to comment.
U.S. Preventive Services Task Force Chair Dr. Sue Curry released a statement standing by the USPSTF guidelines from 2016 recommending screening start at age 50, saying the decision was based on the evidence available at that time.
"The evidence is clear that colorectal cancer screening saves lives," Curry said.
"At the time of the Task Force's review, there was limited data on screening adults younger than age 50. As such, the available evidence led to our current recommendation that adults ages 50 to 75 get screened."
The task force typically updates screening guidelines in five-year cycles, so any new colorectal cancer screening recommendations may not occur until 2021. The task force's recommendation have significant implications for whether a screening test is covered by insurance without cost-sharing, as required by the Affordable Care Act. Under the current law, insurers must cover evidence-based services for adults that have a rating of "A" or "B".
Dr. Nancy You, associate professor of surgical oncology at MD Anderson Cancer Center in Houston, said the different recommended ages among the various organizations might cause confusion among some patients and providers, but she contended that it could present more options.
"For patients who might have concerns and who do want to be more proactive, they have the option of starting a little bit earlier," You said.
Ultimately, You felt the new guidelines will encourage regular screening and raise awareness about the rising mortality rates associated with colorectal cancer. Only 60% of adults over age 50 receive regular screenings, she said.
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