A quiet but significant change is underway in colorectal cancer trends, one that is increasingly affecting adults well before traditional screening age.
Colorectal cancer includes cancers of the colon and rectum, the last segments of the gastrointestinal tract. Colorectal cancers begin as polyps – small growths inside the intestine – that slowly develop into cancer over time. When detected early, colorectal cancer is highly treatable, which is why timely screening and early recognition are so critical.
Since the mid-1990s, rates of colorectal cancer have declined among older adults. In contrast, the rate of colorectal cancer diagnosis among adults under the age of 50 have steadily increased, with an annual rise of approximately 2% among adults ages 20-39. In fact, colorectal cancer is now one of the fastest-increasing cancers in young adults.
And it’s not just a numerical increase; there are increasing cancer burdens as well. Studies have shown that younger patients are more likely to present with later-stage disease and, in some cases, more aggressive cancers. Younger patients may also face unique challenges compared to older adults, including concerns related to fertility, family planning, career development, and financial stability.
In response to these rising rates, screening guidelines have evolved. In recent years, both the American Cancer Society and the U.S. Preventive Services Task Force have lowered the recommended starting age for colorectal cancer screening in average-risk adults from 50 to 45 years.
Encouragingly, these updated screening recommendations are already making an impact, with more adults between 45 and 49 undergoing these life-saving tests.
While expanded screening has improved early detection, researchers continue to investigate why colorectal cancer rates are increasing in younger populations. Several theories are being explored, including:
- changes in diet and lifestyle
- alterations in the gastrointestinal microbiome
- rising obesity rates
- environmental exposures
A major ongoing challenge is in patients younger than the screening age of 45 years old, in whom gastrointestinal symptoms may still be dismissed or attributed to stress, diet, or benign conditions like hemorrhoids or irritable bowel syndrome. Increased awareness of the symptoms of early-onset colorectal will be essential in guiding patients to the proper care going forward.
The symptom most strongly associated with early-onset colorectal cancer is rectal bleeding; other concerning symptoms include persistent changes in bowel habits, unintentional weight loss, and unexplained abdominal pain, cramping, or bloating. When these symptoms persist, they warrant medical evaluation.
Individuals with a family history of colorectal cancer or inflammatory bowel disease are at higher risk and may need earlier screening. However, many young adults diagnosed with colorectal cancer have no known risk factors, highlighting the need for vigilance among both patients and healthcare providers.
Colorectal cancer screening is typically performed with a colonoscopy, which allows a gastroenterologist to sample or remove concerning polyps during the same procedure. Blood-based and stool-based tests are also available for average-risk patients, though any abnormal result will need to be followed with a colonoscopy. Importantly, anyone experiencing concerning symptoms should be evaluated by a gastroenterologist regardless of age or screening history.
Early detection saves lives. Understanding symptoms, recognizing risk, and knowing when screening is appropriate can make a profound difference as the demographics of colorectal cancer continue to change.
