A prominent cancer organization is for the first time recommending Americans initiate colorectal cancer screening at age 45 instead of waiting until age 50, a threshold long endorsed by many other medical groups.
The new guidelines, from the American Cancer Society, would extend routine colorectal cancer screening to an additional 22 million American adults between the ages of 45 and 49 and send a clear message that colorectal cancer, which has been rising in young adults, is no longer just a disease of older people.
Dr. Thomas Weber, co-chairman of an early-age onset colon cancer task group for the National Colorectal Cancer Roundtable but who was not involved in writing the new recommendation, called lowering the age for first screening "a game changer" that could save thousands of lives.
"This is a very, very big deal," said Weber, who is director of surgical oncology for the northwest region of Northwell Health. "Solid epidemiological data from our national cancer registries documents a dramatic increase in the incidence of colon and especially rectal cancer among individuals under the age of 50, and the vast majority of those cases are in the 40- to 49-year-old age bracket."
The guidelines, released Wednesday, were published in CA: A Cancer Journal for Clinicians, a peer-reviewed journal of the American Cancer Society. They do not call for everyone to have a colonoscopy, the gold standard of colon cancer screening. Rather, to maximize the chances that people will take up screening, the cancer society wants physicians to offer patients a choice of six different screening options, from the most invasive procedure, colonoscopy, which can be done every 10 years, to lab tests done on stool samples that can be collected at home, which must be repeated more often and followed by colonoscopy if results are positive.
The group estimates some 16,450 new cases of colon or rectal cancers will be diagnosed this year in Americans under 50.
Dr. Alan F. Shikoh, a gastroenterologist at CHI Memorial Hospital, said he was "not at all surprised" by the new recommendations.
"There's been a shift toward younger and younger cases of colon cancer, so it just makes us a little more alarmed," he said. "Interestingly enough, I've had patients already ask about it - either they know somebody who had colon cancer at a fairly young age, or perhaps there were some things in the lay literature."
In 2014, 43 percent of colorectal cancer cases in those under 50 were in adults ages 45 to 49, according to Rebecca L. Siegel, an epidemiologist with the American Cancer Society and the lead author of several reports showing a rise in colorectal cancers in adults as young as their 20s and 30s.
The group does not recommend routine screening for those under 45, because the absolute rates of cancer in those age groups are still very low and there are risks associated with procedures like colonoscopies, including a perforated bowel.
More than 140,000 Americans are expected to be given a diagnosis of colon or rectal cancer this year. The disease leads to more than 50,000 deaths annually, making it the second leading cause of cancer fatalities among American adults.
The majority of colorectal cancers are still found in older people, with nearly 90 percent of all cases diagnosed in people over 50. But while incidence and deaths among those 55 and older have been declining in recent decades, at least in part because of screening that results in removal of precancerous polyps and early detection of cancer, recent analyses have documented a 50 percent rise in colorectal cancer rates among adults under 50 between 1994 and 2014.
While colorectal cancer rates dropped steadily for people born between 1890 and 1950, they have been increasing for every generation born since 1950. A recent American Cancer Society study by Siegel found that adults born in 1990 have twice the risk of colon cancer and four times the risk of rectal cancer compared to the risk adults born in 1950 faced at a comparable age.
The new guideline puts the American Cancer Society at odds with other national organizations that recommend starting screening at 50 and raises questions about whether health insurers will pay for the earlier tests.
The influential Preventive Services Task Force decided against lowering the screening age to 45 when it updated its recommendations in 2016 and continues to recommend starting routine screening at 50.
Shikoh said colon cancer is "very unique" in that a screening tool like the colonoscopy exists to help providers detect cancer before it strikes, which isn't the case with other notorious cancers like breast cancer, lung cancer or prostate cancer.
"Not that there aren't some screening strategies out there, but we don't have the potential to remove precancerous growths before they cause a problem," he said. "So what we're really trying to get across with the recommendation is that we will benefit even more patients if we get more people to be screened at this slightly younger age."
Shikoh also emphasized that the new recommendation is for average risk individuals, not people with a family history of colon cancer, who should be screened even earlier in life.
Staff writer Elizabeth Fite contributed to this story.