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Younger whites demonstrate ‘concerning’ increase in colon cancer mortality
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Colorectal cancer mortality rates have increased steadily among white individuals who are younger than standard screening age, according to a study published in JAMA.
The trend of increased colorectal cancer mortality — which began in 1995 for those aged 30 to 39 years, and in 2005 for those aged 40 to 54 years — mirrors a trend of increased colorectal cancer incidence among younger whites.
Among black individuals in the same age groups, colorectal cancer incidence has remained stable and mortality rates have declined steadily since 1970.
“We do not have an answer for why colorectal cancer is increasing in whites but not in blacks,” Rebecca L. Siegel, MPH, director of surveillance information at the American Cancer Society, told HemOnc Today. “It is not consistent with patterns in major risk factors like obesity, physical activity, alcohol consumption and smoking, which are similar by race. The unknown mechanism behind the increase in colorectal cancer in whites makes it that much more concerning.”
Colorectal cancer mortality has been declining overall, but incidence has been rising in the United States among adults aged younger than 55 years since the mid-1990s. The increase has been confined to white men and women and has been most rapid in metastatic disease.
Researchers analyzed National Center for Health Statistics records to determine colorectal cancer mortality rates among individuals aged 20 to 54 years by race.
From 1970 through 2014, 242,637 people (54% men; 80% white; 17% black; 3% other races) aged 20 to 54 years died of colorectal cancer at a median age of 49 years.
Overall mortality rates among those aged 20 to 54 years declined from 6.3 per 100,000 in 1970 to 3.9 per 100,000 in 2004, then increased by 1% (95% CI, 0.7-1.4) annually to 4.3 per 100,000 in 2014.
The increase occurred only in white individuals, whose mortality rates increased by 1.4% (95% CI, 1.1-1.8) annually, from 3.6 per 100,000 in 2004 to 4.1 per 100,000 in 2014.
“This indicates that the increase in incidence is not solely due to more colonoscopy use and increased detection, but a true increase in disease occurrence that is of sufficient magnitude to outweigh improvements in survival that have occurred in all age groups because of better treatment,” Siegel said.
Mortality rates declined among black individuals by 0.4% (95% CI, –0.6 to –0.3) annually to 1.1% (95% CI, –1.5 to –0.7) annually, from 8.1 per 100,000 in 1970 to 6.1 per 100,000 in 2014.
Among other races combined, mortality rates declined from 1970 through 2006, then stabilized through 2014.
Age-stratified analyses showed mortality rates in white individuals aged 20 to 29 years remained stable from 1988 through 2014. However, from 1995 through 2014, mortality increased by 1.6% (95% CI, 1.2-2.1) annually for those aged 30 to 39 years. From 2005 to 2014, mortality increased by 1.9% (95% CI, 1.2-2.5) annually for those aged 40 to 49 years, and by 0.9% (95% CI, 0.1-1.6) annually for those aged 50 to 54 years.
Increased mortality was particularly unexpected among those aged 50 to 54 years, for whom screening has been recommended since the 1970s.
“Colorectal cancer death rates are increasing in people in their early 50s, for whom screening has been recommended for decades,” Siegel said. “This was particularly surprising because colorectal cancer screening helps lower death rates in two ways — by preventing cancer and by detecting it early when treatment is more effective.”
Rising death rates in those aged 50 to 54 years likely reflect the aging of more recent birth cohorts, who have higher risk for colorectal cancer, as well as lower screening rates compared with those aged 55 years and older, which were 46% vs. 67% in 2015, Siegel noted.
“Delayed initiation of screening is likely behind these lower rates, as well as other barriers like insurance coverage, which is lower in ages 50 to 54 years than older adults because of the universal coverage offered by Medicare beginning at 65 years,” Siegel said.
In contrast, colorectal cancer mortality rates in blacks decreased over the entire study period among those aged 20 to 49 years and since 1993 in those aged 50 to 54 years.
“This racial disparity is consistent with incidence, but in contrast to trends for major risk factors for colorectal cancer, like obesity, which has increased across all racial and ethnic groups,” Siegel said. “This suggests that the obesity epidemic is probably not wholly responsible for the increase in disease.”
Limitations of the study included its ecologic nature and inaccuracies in about 5% of all death certificates listing colorectal cancer as the underlying cause of death.
There are three key factors that lower risk for colorectal cancer mortality, according to Siegel:
Maintain a healthy bodyweight. Be physically active on a regular basis; do not consume excess alcohol; do not smoke; and eat a healthy, primarily plant-based diet that includes the recommended amount of calcium and minimizes red/processed meat;
Follow guidelines for screening. Those at average risk for colorectal cancer should schedule a colonoscopy at age 50 years. Those at elevated risk, which includes people whose parent or sibling had polyps, should talk to their doctor about screening before age 50 years; and
Know the symptoms. Persistent bleeding from the rectum or in the stool, cramping and change in bowel habits are the most common symptoms associated with colorectal cancer. The 5-year survival for colorectal cancer diagnosed at a localized stage is 90%, yet 28% of young patients are diagnosed at a distant stage, for which 5-year survival is just 14%. – by Chuck Gormley
For more information:
Rebecca L. Siegel, MPH , can be reached at the American Cancer Society, 250 Williams St. NW, Atlanta, GA 30303; email: rebecca.siegel@cancer.org.
Disclosures: The American Cancer Society funded this study. The researchers report no relevant financial disclosures.
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