The increase in colorectal cancer (CRC) mortality among younger adults in the United States has already been highlighted, but new data show that the uptick is seen among white men and women in their early 50s, many of whom were current in their screening for CRC.
No such increase has been seen among black adults of the same age, note researchers from the American Cancer Society (ACS).
The new finding is in a report published online August 11 in the Journal of the American Medical Association.
Analysis of CRC mortality among persons aged 20 to 54 years by race from 1970 through 2014 shows that rates per 100,000 population declined from 6.3 in 1970 to 3.9 in 2004, but have since been increasing by 1% annually.
However, this increase was seen only in white adults, among whom mortality rates increased by 1.4% annually, say Rebecca L. Siegel, MPH, and colleagues from the ACS.
In black adults of the same age, CRC mortality rates declined by 0.4% annually to 1.1% annually.
This finding is consistent with increasing incidence rates seen in white but not in black adults, the study authors comment. They note that among other races combined, mortality rates declined in the period 1970-2006, after which rates were stable.
"Although CRC mortality is declining overall, trends for all ages combined mask patterns in young adults, which have not been comprehensively examined," Siegel and colleagues warn. These disparate racial patterns conflict with trends in major CRC risk factors, such as obesity, which are similar in whites and blacks, the study authors point out. They also "highlight the need for earlier CRC detection through age-appropriate screening and more timely follow-up of symptoms."
Particularly surprising was the finding that 44% of CRC deaths were in young white adults who had been screened as per 2013 guidelines, Siegel told Medscape Medical News. "Increasing death rates not only reflect inadequate screening in this population but probably also elevated risk of disease, as young cohorts with increased risk are aging," she said.
The reason behind these racial differences for trends in CRC mortality rates remains unknown, which is "one of the reasons it is so concerning," Siegel added. "While it is likely that increases in excess body weight, less physical activity, and unhealthy diet are playing a role, the racial disparity may indicate that there are other factors influencing the rise in disease risk."
To reduce CRC morbidity and mortality in young and middle-aged adults, as well as in older adults, clinicians need to be educating patients about the CRC symptoms, including bleeding from the rectum, blood in the stool, and abdominal cramping, she said.
Physicians also need to be following patients who present with persistent symptoms. "The burden of CRC is shifting to people under 55, and detecting cancer early in these patients is their best chance of beating the disease," Dr Siegel said, noting that the 5-year relative survival rate for localized CRC is 90%.
As previously reported by Medscape Medical News, the decision of whether to recommend screening for younger populations requires a formal analysis of risks and benefits. In addition, patient navigation is crucial to adherence to CRC screening. Fecal occult blood testing is particularly vulnerable to nonadherence because of the need for annual testing.
Details of the Analysis
For the analysis, 1970-2014 CRC mortality rates per 100,000 population were stratified by race. Age was adjusted to the 2000 US population at four stages: 20-29, 30-39, 40-49, and 50-54 years. The data, which were taken from death certificates, reflect more than 99% of deaths in all 50 states and the District of Columbia, the investigators point out.
From 1970 to 2014, 242,637 people aged 20 to 54 years died from CRC; the median age was 49 years. Some 54% were men; 80% were white; and 17% were black.
In whites aged 20 to 29 years, mortality trends were stable from 1988 to 2014. However, from 1995 to 2014, CRC mortality rates in whites aged 30 to 39 years increased by 1.6% annually; it increased by 1.9% annually for those aged 40 to 49 years, and by 0.9% annually in whites aged 50 to 54 years.
In black adults, rates decreased over the entire study period among those aged 20 to 49 years. Since 1993, rates decreased in blacks aged 50 to 54 years.
"These trends are consistent with CRC incidence from 1998-2009 among those younger than 50 years, which was stable in black individuals, but increased in white individuals by 1.5% annually for local-stage and regional-stage disease and by 3% annually for distant-stage disease," the investigators write.
Although 5-year survival has improved in persons aged 15 to 64 years, mortality can increase "if increased CRC occurrence is of sufficient magnitude to outweigh improvements in survival," they note. "Increased mortality is particularly unexpected among those aged 50 to 54 years, for whom screening has been recommended since the 1970s."
Limitations of the study include inaccuracies in death certificates listing CRC as the underlying cause of death. This is estimated to include about 5% of all death certificates.
This study was funded by the American Cancer Society. The study authors have disclosed no relevant financial relationships.
JAMA. Published online August 11, 2017. Abstract