Colorectal cancer is no longer a disease seen primarily in older adults. New data show that nearly half — 45% — of all new colorectal cancer diagnoses now occur in people under age 65. In 1995, that number was just 27%. During the same period, rates among adults 65 and older have declined.

The shift is particularly striking for rectal cancer. Once accounting for about 27% of colorectal cancers in the mid-2000s, rectal tumors now represent nearly one-third of cases. From 2018 to 2022, rectal cancer diagnoses increased by approximately 1% per year across all adult age groups.

Researchers have not yet identified a clear explanation for this rise.

For decades, colon and rectal cancers were considered conditions that developed later in life. The recent increase among younger adults has altered that assumption. Over the past five years, clinicians have reported seeing more patients in their 20s, 30s, 40s, and early 50s with newly diagnosed disease.

Long-Term Trends by Age

Since the late 1990s, colorectal cancer rates have:

  • Increased by 3% annually among adults ages 20 to 49
  • Increased by 0.4% annually among adults ages 50 to 64
  • Decreased by 2.5% annually among adults 65 and older

The reasons for these age-specific trends remain under investigation. Lifestyle factors, environmental exposures, changes in diet, and alterations in the gut microbiome are among the areas being studied. At this time, no single cause has been confirmed.

Delays in Diagnosis Raise Concern

Younger patients often face delays between the onset of symptoms and a confirmed diagnosis. Reports suggest a gap of four to six months from first symptoms to diagnosis in some cases. During this time, the cancer may continue to grow.

Part of the delay may stem from assumptions — by patients or clinicians — that colorectal cancer is unlikely in younger adults. As a result, symptoms may be attributed to less serious conditions.

Recognizing the Symptoms

Colorectal cancer includes cancers of the colon and rectum. The colon makes up most of the large intestine. The rectum is the final segment, located just before the anus.

Symptoms can differ depending on the tumor’s location.

Colon cancer symptoms may be subtle and include:

  • Persistent fatigue
  • Abdominal discomfort or cramping
  • Bloating
  • Unexplained weight loss

Rectal cancer symptoms often appear more visibly and may include:

  • Bright red blood on toilet paper or in the toilet bowl
  • A feeling of urgency to have a bowel movement
  • A sensation that the bowel has not fully emptied

Any persistent change in bowel habits, bleeding, or unexplained symptoms should be evaluated by a healthcare professional. Early reporting allows for earlier testing and, if needed, earlier treatment.

Screening: When to Start

For many years, routine colorectal cancer screening began at age 50. In 2021, the U.S. Preventive Services Task Force lowered the recommended starting age to 45 for adults at average risk.

Some individuals may need screening earlier, including those with:

  • A family history of colorectal cancer
  • A history of precancerous polyps
  • Inflammatory bowel disease

Despite updated recommendations, screening participation remains incomplete. Only slightly more than one-third of adults ages 45 to 49 are currently screened. Among people younger than 50, roughly three-quarters of colorectal cancers are diagnosed at an advanced stage.

As diagnoses continue to shift toward younger age groups, health authorities may reevaluate current screening guidelines in the coming years.

There is also growing discussion about expediting diagnostic testing for people under 45 who develop concerning symptoms. In some cases, patients experience prolonged referral cycles before receiving definitive testing, such as a colonoscopy. Reducing these delays is considered a priority to prevent disease progression.

The Broader Impact

Colorectal cancer is now the leading cause of cancer-related death in adults under age 50 in the United States. Projections estimate approximately 158,850 new colorectal cancer cases in 2026. About 55,230 deaths are expected, with nearly one-third occurring in people under 65.

Reducing Risk

More than half of colorectal cancer cases are linked to modifiable risk factors. These include:

  • Tobacco use
  • Excess alcohol consumption
  • Physical inactivity
  • Overweight and obesity

Diet also plays a role. Increasing intake of fiber, vegetables, fruits, and whole grains — and limiting processed meats — is associated with lower risk.

While not all colorectal cancers are preventable, many risk factors can be addressed through lifestyle changes and regular medical care. Early screening, attention to symptoms, and prompt evaluation remain the most effective tools currently available to reduce advanced disease and improve outcomes.