Mortality rates from colorectal cancer have increased among younger white adults, finds a troubling new study that adds to the research on a cancer that generally is considered one of the more preventable types.
The study finds that mortality from colorectal cancer among white adults in their 30s, 40s and early 50s began increasing from the mid-1990s after decades of decline. This trend is consistent with previous work by these researchers that reported increases in colorectal cancer incidence in this same age group.
The study was published in the Journal of the American Medical Association.
Colorectal cancer is the second leading cause of cancer-related deaths and the third most common cancer in the United States. AICR research shows there are many lifestyle factors linked to this cancer. Physical activity and foods high in fiber link to lower risk; alcohol, being overweight, processed meats and high amounts of red meat link to increased risk.
Other risk factors for colorectal cancer include inflammatory bowel diseases, such as Crohns, family history and smoking.
"The study is interesting, but distressing, to see a cancer that is so preventable increasing in any age group, but particularly among younger people where screening is not typically recommended," said AICR Director of Nutrition Programs Alice Bender, MS, RDN. "But we do know that healthy lifestyle habits reduce risk for colorectal along with other cancers and other chronic diseases. So it makes sense to instill these habits -- being active and healthy eating -- starting at a young age."
AICR estimates that 47 percent of colorectal cancer cases in the US are preventable each year through diet, physical activity and weight management.
Rising Rates, New Questions
For the study, researchers analyzed colorectal cancer mortality among persons ages 20 to 54 years by race from 1970 through 2014 using government data. From 1970 to 2004 mortality rates declined overall. That year death rates began to increase by 1 percent annually among white individuals, getting to 4.1 deaths per 100,000 individuals in 2014.
Among age groups by decade, mortality remained stable in white individuals in their 20s. From the mid 1990s to 2014, deaths from colorectal cancer increased 1.6 percent yearly among those ages 30 to 39. From 2005 to 2014 it increased by almost 2 percent per year for those ages 40 to 49 and almost 1 percent per year for those in their early 50s.
Rates declined in black individuals in every age group.
While the risk remains relatively low for young and middle-aged adults, the rising mortality rates are concerning because it appears to be “a true and perplexing escalation in disease occurrence," said lead study author Rebecca Siegel, MPH, American Cancer Society in a news release.
Screening has long been recommended for individuals ages 50 and upwards and so this increase was particularly unexpected, the authors write. Screening prevalence has increased for all age groups over 50, but is lower in people 50 to 54 than in those 55 and older, according to the National Health Interview Survey.
This new report brings up many questions that need more research, such as why rates are increasing among whites and not in blacks when major risk factors like obesity have become more prevalent across the board. "Whether there are specific lifestyle habits, like alcohol and diet, that may impact risk for younger people in a different way is still undetermined," says Bender. "Yet lifestyle matters - for lower cancer risk and overall health."
The study was funded by the American Cancer Society.
Source: Colorectal Cancer Mortality Rates in Adults Aged 20 to 54 Years in the United States, 1970-2014, doi:10.1001/jama.2017.7630.
AICR and World Cancer Research Fund. Food, Nutrition, Physical Activity, and the Prevention of Colorectal Cancer. 2011.
Centers for Disease Control and Prevention. What are the Risk Factors for Colorctal Cancer?
Published on August 23, 2017