A new study found that the proportion of adults diagnosed with colorectal cancer under age 50 in the United States has continued to increase over the past decade.
To determine recent trends in colorectal cancer rates, researchers examined information from the National Cancer Database registry. From 2004 to 2015, 130,165 patients under age 50 and 1,055,598 patients over age 50 were diagnosed with colorectal cancer.
Among the major findings:
- The proportion of patients diagnosed with colorectal cancer under the age of 50 rose from 10% in 2004 to 12.2% in 2015.
- The proportion of young onset disease was higher in African American and Hispanic populations than non-Hispanic whites throughout 2004 to 2015.
- 51.6% of younger adults were diagnosed with more advanced stages of cancer (stage III/IV) versus 40% in those older than 50 years.
- Diagnoses in men under the age of 50 years rose only in non-Hispanic whites, while in women, Hispanic and non-Hispanic whites had an increase in younger diagnoses over time.
- Rates of colorectal cancer diagnosis in young adults increased over time regardless of income level. The highest proportion of young adult diagnoses occurred in the top income category.
- The proportion of colorectal cancers diagnosed in younger individuals rose in urban areas, but not in rural areas.
The researchers noted that the cause of increasing rates of colorectal cancer in younger patients is unclear, but emerging research suggests that it may be a combination of increases in body weight and changes in gastrointestinal bacteria.
The American Cancer Society's guideline for colorectal cancer screening recommends that average-risk adults aged 45 years and older undergo regular screening, either with colonoscopy or with alternatives such as fecal immunochemical tests and fecal occult blood tests.