Research indicates that there’s an uptick in colorectal cancer cases among adults under 50, with recent studies suggesting that increased screening could explain many of these recent findings—though it doesn’t fully account for the overall trend.
In 2018, the American Cancer Society revised its guidelines, advising adults at average risk to begin screening at 45 rather than the previously recommended age of 50.
Subsequently, in 2021, the US Preventive Services Task Force also adjusted the starting age for screening from 50 to 45.
This shift in guidelines is linked to a rise in early-stage diagnoses, yet it doesn’t clarify the broader increase in cases among younger adults, a trend that started in the mid-90s and includes late-stage cancers as well. Colorectal cancer encompasses both colon cancer, which originates in the colon, and rectal cancer, which begins in the rectum.
Elizabeth Schafer from the American Cancer Society mentioned in an email that the reasons behind this rising incidence remain unclear, though various research efforts are underway. These investigations explore various factors, from microplastics to ultra-processed foods and other changes to the gut ecosystem since the late 20th century.
Dr. Joseph Rinaldi, a gastroenterologist at Montefiore Einstein Comprehensive Cancer Center, stated that lower screening ages likely help detect cancers sooner, but more research is needed to uncover the root causes of the overall increase in colorectal cancer among younger people.
He added that it’s likely there are factors other than screening influencing this rise, implying that there’s still a lot of work to do in identifying environmental, genetic, or population-based causes that could be targeted for prevention.
New research from the American Cancer Society published in JAMA reveals that the percentage of U.S. adults aged 45 to 49 who are up to date on screening rose from 20.8% in 2019 and 19.7% in 2021 to 33.7% in 2023.
Schafer expressed enthusiasm about this increase, noting that they had been anticipating better screening rates in this age group, but the significant aspect is translating those rates into earlier diagnoses, which can lead to less aggressive treatment and saved lives.
Another study from the American Cancer Society published the same day found that the incidence of early-stage colorectal cancer among 45- to 49-year-olds rose from 9.4 cases per 100,000 in 2019 to 11.7 per 100,000 in 2021, and then to 17.5 per 100,000 in 2022.
This marks a 50% relative increase between 2021 and 2022.
Schafer, the lead author of the second study, noted that if screening had been the sole factor driving this rise, the increase would have been primarily in early-stage rather than late-stage cases.
She commented that localized stage diagnoses were uncommon in this age bracket before screening since symptoms typically do not present at that stage. It was surprising, she said, to see such a significant rise in early-stage instances within this newly screened population.
In light of the ongoing rise in colorectal cancer among younger adults, health experts are urging this demographic to be aware of warning signs and to seek screening when they are eligible.
The signs and symptoms to watch for
More than half of individuals diagnosed with colorectal cancer before age 50 are too young for screening as they have not reached the recommended age of 45. Additionally, many eligible individuals remain unscreened, according to Jessica Star from the American Cancer Society.
Regardless of their screening eligibility, people should monitor for colorectal cancer symptoms and consult their doctors if they experience any, she advised.
Statistics reveal that about 1 in 23 men and 1 in 25 women in the U.S. will receive a colorectal cancer diagnosis in their lifetime.
Rectal bleeding stands out as the most common symptom; Star noted that 41% of patients under 50 report this symptom, compared to 26% among older patients. Abdominal cramping or pain are also frequent complaints.
Star emphasized the need for young individuals to feel comfortable discussing these symptoms, as it could genuinely be life-saving.
Other critical symptoms include ongoing changes in bowel habits, alterations in stool shape, reduced appetite, and weight loss. Anyone experiencing these symptoms over several weeks should consult a doctor. If younger individuals find their concerns dismissed, it’s wise to seek a second opinion, as many have faced the misdiagnosis of hemorrhoids only to later discover cancer.
Kelly Spill, 33, recounted her experience after giving birth, explaining how her doctors attributed her symptoms to postpartum recovery and hemorrhoids. Alarm bells went off when she observed unusual blood in her stool.
When symptoms reappeared, she documented the findings and presented them to her doctor, who promptly scheduled a colonoscopy—leading to her diagnosis of stage III rectal cancer at just 28.
She underscored the importance of self-advocacy, noting, “If I hadn’t pushed and pushed, who knows where I’d be, especially as a new mom.”
Undergoing treatment with an immunotherapy drug called dostarlimab, Spill is now a healthy mother of three, cancer-free.
Screening plays a crucial role in minimizing colorectal cancer risks, as nearly all colorectal cancers begin as precancerous polyps. Early identification and removal of these polyps can prevent cancer development.
Current average risk screening methods include stool-based tests either annually or every three years, traditional colonoscopies every ten years, virtual colonoscopies every five years, or sigmoidoscopies every five years.
A different study unveiled that individuals newly eligible for screening who received a mailed fecal test kit were more likely to complete screening compared to those presented with a choice of tests.
Schafer highlighted the ongoing concern of increasing screening access for those without healthcare, a group that showed no significant increase in this study.
Despite rising screening numbers, over one in three adults aged 45 and older are still not getting the recommended screenings, as reported by the National Colorectal Cancer Roundtable.
There are additional preventive measures people can adopt.
According to Star, lifestyle decisions can make a difference at any age, including not smoking, maintaining a healthy weight, staying active, reducing alcohol intake, and consuming a diet rich in whole grains, fruits, and vegetables while low in red and processed meats.
The American Cancer Society has noted that over half of all colorectal cancers in the U.S. can be linked to these modifiable risk factors.
Rinaldi emphasized the importance of a physically active lifestyle and healthy weight, indicating a connection between obesity and early-onset disease. He further advocated for reducing tobacco, refined grains, and sugary drinks, and focusing on a plant-based diet with plenty of fiber, as this may benefit colon health.
