Rising Proportion of Young Individuals With Rectal and Colon Cancer.

BACKGROUND: Recent trends have identified increasing number of young individuals with rectal and colon cancers. These individuals, who are younger than 50 years old, in most instances would not meet screening guidelines. We aimed to report the characteristics and trend of the rising proportion of young individuals being diagnosed with rectal and colon cancers at our institutions. PATIENTS AND METHODS: This study included 3381 rectal and colon cancer patients from the Mayo Clinic cancer registry from 1972 to 2017 who were diagnosed with rectal or colon cancer and who were < 50 years old. Patient and cancer characteristics are described. The Cochran-Armitage trend test was used to see if the change in percentage diagnosed at age < 50 years had a significant trend over the years. A linear regression model was fit to estimate the percentage change per year when the trend was approximately linear.
RESULTS: The percentage of patients diagnosed with rectal or colon cancer in different age categories over the years showed a rising trend for individuals aged < 50. Most of these tumors were distal (rectum, left-sided colon, and right-sided colon were 49.8%, 28.8%, and 21.4%, respectively). This was more so for patients < 50 diagnosed with rectal cancer, which showed a linear increase at a rate of 0.26% per year (P < .001).
CONCLUSION: Our study affirms the rising proportion of colorectal cancers found in young individuals, with a linear ongoing rise of rectal cancers in particular. This may have implications for the current screening recommendations for colorectal cancers, which are already being revised.