Studies Forecast More CRC in Young Adults and Find Higher Mortality Among the Least Educated

Findings from two studies are shining a light on demographic and socioeconomic factors impacting who will be diagnosed with colorectal cancer (CRC), who is more likely to die from it, and what preventive measures might make a difference.

The first, published online November 5, 2014 in JAMA Surgery, suggests that the incidence of colon and rectal cancer will rise by 90% and >124%, respectively, in individuals aged 20-34 by 2030.

This retrospective analysis by researchers at The University of Texas MD Anderson Cancer Center expanded on prior studies of CRC trends to generate quantitative estimates of risk of CRC among people younger than age 50—the traditional recommended screening age for the general public. They used Surveillance, Epidemiology, and End Results (SEER) data on more than 393,000 patients with histologically confirmed CRC between 1975 and 2010 and found that the annual incidence rate for CRC in patients younger than 34 is on the rise for all disease stages.

The authors point to lifestyle and behavioral factors such as obesity, lack of physical activity, and a Western diet as major risk factors for CRC, though the exact causes of the predicted increases are not known.

“This is an important moment in cancer prevention,” said principal investigator George J. Chang, MD, MS, associate professor, Departments of Surgical Oncology and Health Services Research at MD Anderson. “We’re observing the potential real impact of CRC among young people if no changes are made in public education and prevention efforts. This is the moment to reverse this alarming trend.”

Though the authors said the findings do not suggest changing the recommended general screening age, clinicians should be watching for CRC symptoms which might typically be dismissed in younger adults.

The analysis did yield some good news for patients aged 50 and older whose rates of CRC are expected to continue their downward trend. The researchers’ predictive model suggests that incidence of colon cancer will decline by an estimated 21% in 2020 and nearly 38% in 2030 in this group, and the incidence of rectal cancer by 19% and 34%, respectively, with the largest decrease expected for patients aged >75 years.

The second study by investigators at the American Cancer Society (ACS) and published online November 10, 2014 in the Journal of Clinical Oncology found that approximately 50% of deaths from CRC among individuals aged 25 to 64 are associated with socioeconomic inequalities and are thus preventable.

Over the past few decades, study authors noted, there has been a switch of who is most likely to die of CRC, from whites of higher socioeconomic status living in northern states, to individuals of lower socioeconomic status, those who are black, and those residing in southern states.

ACS researchers, led by Ahmedin Jemal, PhD, drew upon National Vital Statistics data from the CDC’s National Center for Health Statistics for their analysis. Three broad, educational categories were used as a marker of socioeconomic status (≤12 years of education, 13-15 years, and ≥16 years). They found that among individuals aged 26-64, those with the least education had higher CRC death rates in virtually all states, with “substantial geographic disparities” existing within educational levels. Non-Hispanic whites with the lowest educational attainment in New Mexico, for example, had triple the risk of CRC death as non-Hispanic whites with the highest educational attainment.

“We found that the least educated persons in the United States have a disproportionately higher burden of CRC death rate, regardless of race or state of residence,” study authors concluded. “The majority of premature deaths from CRC in southern states and half the deaths nationwide are potentially avertable through the elimination of racial/ethnic, socioeconomic, and geographic inequalities.”

Nearly 137,000 people will be diagnosed with CRC in the United States this year, and more than 50,000 will die of the disease. CRC is the third most common cancer among men and women, and the third leading cause of cancer death.