Colorectal cancer, traditionally seen as a disease affecting older adults, is increasingly being diagnosed in children, teens, and young adults. Over the past two decades, the incidence of colorectal cancer in these younger age groups has risen dramatically, with some age brackets experiencing increases of several hundred percent1 2. This alarming trend highlights a growing public health concern that demands urgent attention to understand causes and improve early detection3 .
Increasing Colorectal Cancer Diagnoses in Youth
Early-onset colorectal cancer (EOCRC), defined as colorectal cancer diagnosed before age 50, has nearly doubled in incidence among younger adults since the early 1990s4 . While colorectal cancer remains more common in older adults, the fastest rise in new cases is occurring in people under 50 years old5 . Notably, incidence rates for adults aged 40–44 have increased significantly, with rates rising from 14.6 per 100,000 in 1999 to 20 per 100,000 in 2020, a 37% increase6 7.
Even more striking is the increase among adolescents and children, though colorectal cancer remains rare in these groups. For example, the incidence rate among teens aged 15 to 19 rose from 0.3 per 100,000 in 1999 to 1.3 per 100,000 in 2020, representing a 333% increase7 . Children aged 10 to 14 have seen an even more dramatic 500% rise in colorectal cancer diagnoses during this period1 2. Despite these increases, fewer than 100 children are diagnosed with colorectal cancer annually in the United States, underscoring the rarity but growing concern of this disease in youth8 9.
The causes of this rise in early-onset colorectal cancer are not fully understood. Traditional risk factors such as obesity, poor diet, physical inactivity, alcohol use, and tobacco smoking are implicated but do not completely explain the increase in younger populations10 11. Other potential contributors include changes in the gut microbiome, antibiotic use, environmental exposures, and genetic predispositions12 3. Approximately 20% to 30% of early-onset cases are linked to hereditary cancer syndromes or familial colorectal cancer, but the majority are sporadic with no known inherited cause13 1112.
“When the incidence of a disease changes by generation, that suggests the culprit is something in the environment, rather than something biological.”
— Kimmie Ng3
Children with inflammatory bowel diseases such as Crohn disease or ulcerative colitis are at increased risk of colorectal cancer, likely due to chronic inflammation of the colon8 . Symptoms in children and teens often depend on tumor location and may include abdominal pain, constipation or diarrhea, blood in the stool, unexplained weight loss, nausea, vomiting, and anemia8 14. Unfortunately, colorectal cancer in children is often diagnosed at advanced stages, with spread to lymph nodes or other abdominal organs, making treatment more challenging8 .
| Age Group (years) | Incidence Rate per 100,000 (1999) | Incidence Rate per 100,000 (2020) | Percentage Increase |
|---|---|---|---|
| 10–14 | 0.1 | 0.6 | 500% |
| 15–19 | 0.3 | 1.3 | 333% |
| 20–24 | 0.7 | 2.0 | 185% |
| 40–44 | 14.6 | 20 | 37% |
| Sources: 72 | |||
Reversing the Rising Colorectal Cancer Trend
Although colorectal cancer incidence is increasing fastest in younger adults, older adults continue to have the highest overall rates and mortality5 . Current screening guidelines recommend starting colorectal cancer screening at age 45 for average-risk adults, reflecting the shift toward earlier disease onset16 . However, routine screening in children and teens is not justified due to the rarity of colorectal cancer in these groups17 .
“If anyone has any change in their bowel habits, if they have any bleeding—even if they think it's a hemorrhoid, and it doesn't go away—just get a colonoscopy.”
— Vikram Reddy15
Early diagnosis is critical to improving outcomes. Raising awareness of colorectal cancer symptoms such as rectal bleeding, prolonged constipation or diarrhea, unexplained weight loss, and abdominal pain can help prompt timely medical evaluation14 18. Persistent gastrointestinal symptoms in young adults should lead to consideration of colorectal cancer screening, especially if there is a family history or other risk factors18 19.
Family history communication gaps contribute to missed opportunities for early screening. Expanding screening to at-risk younger populations could prevent many early-onset colorectal cancers19 5. Ongoing research aims to optimize risk assessment and screening strategies tailored to younger adults11 .
Key lifestyle factors associated with colorectal cancer risk include:
“We don't understand a lot about the causes, the biology, or how to prevent early onset of the disease.”
— Phil Daschner3
- Obesity and overweight status10 15
- Diets high in processed and red meats, low in fiber, fruits, and vegetables10 15
- Physical inactivity and sedentary behavior, including increased screen time3
- Tobacco smoking and heavy alcohol use10 15
However, these traditional risk factors do not fully explain the rise in early-onset colorectal cancer, suggesting other environmental and biological factors may be involved11 20. Changes in the gut microbiome and exposure to pollutants, chemicals, and pesticides are under investigation as potential contributors3 .
Public health efforts focus on education, research investment, and tailored screening strategies to address this emerging challenge21 22. Prevention strategies emphasize lifestyle modifications such as maintaining a healthy weight, increasing physical activity, improving diet quality, quitting smoking, and limiting alcohol intake15 .
