Over the past decade, the proportion of younger adults diagnosed with colorectal cancer (CRC) has continued to increase, according to new data from a study published in CANCER.
 
Several studies have indicated that rates of CRC have been climbing among adults under the age of 50 over time, but the reason for this increase has remained unclear. In response to this trend, many CRC screening guidelines, including those from the American Cancer Society, lowered the recommended age to start screening from 50 to 45 years.  
 
For the study, the researchers examined information from the National Cancer Database registry, which includes more than 70% of new cancer cases in the United States, to determine recent trends in CRC rates.
 
Based on the data, 130,165 patients under age 50 and approximately 1.06 million patients over age 50 were diagnosed with CRC from 2004 to 2015. The study showed a 10% increase in 2004 and a 12.2% increase in 2015 among patients diagnosed with CRC under the age of 50. Young-onset disease was more prevalent in African American and Hispanic populations than non-Hispanic white populations during this time, according to the data.
 
Overall, younger adults presented with more advanced disease, with approximately half of younger adults diagnosed with either stage 3 or stage 4 disease compared with 40% in those older than 50 years. CRC diagnosis rates in younger adults increased regardless of income level, with the highest proportion of diagnoses occurring in the top income category. However, the findings showed that although the proportion of young-onset disease diagnoses rose in urban areas, there was no increase in rural regions.
 
At the 2019 Hematology/Oncology Pharmacy Association Annual Conference, Amber Draper, PharmD, BCOP, clinical pharmacist at Winship Cancer Institute, noted that CRC is closely linked to lifestyle and dietary factors and that increasing rates of obesity and sedentary lifestyles could be contributing to higher diagnosis rates.  
 
“So encouraging our patients to be more active, to have a healthier diet, not to smoke, to reduce alcohol intake, those are all things that we can do to reduce the risk of colon cancer,” Draper said in a video interview with Specialty Pharmacy Times®.
 
The study authors indicated that a combination of increased body weight and changes in gastrointestinal bacteria may partly explain the trend. They concluded that the findings should be considering in the ongoing discussion of screening guidelines.
 
“Because the number of colorectal cancers from inherited causes are much higher in younger individuals, it is unknown whether screening for sporadic cases in a group with such low disease rate can result in a favorable balance of harms and benefits,” Chyke Doubeni, MD, MPH, of the University of Pennsylvania, wrote in an accompanying editorial. “It is therefore imperative that the various hypotheses for increasing colorectal cancer incidence among people younger than 50 be rigorously tested to determine if changing the current screening age in people who are not at increased familial risk represents the most appropriate public health response.”
 
References
 
Goodgame B, Virostko J, Capasso A, et al. Recent trends in the age at diagnosis of colorectal cancer in the US National Cancer Data Base, 2004-2015. CANCER. 2019. https://doi.org/10.1002/cncr.32347
 
Doubeni CA. Early-onset colorectal cancer: What reported statistics can and cannot tell us and their implications. CANCER. 2019. https://doi.org/10.1002/cncr.32346