A new report from the American Cancer Society (ACS) have shown that the number of colorectal cancer is increasing among young adults.
Published in CA: A Cancer Journal for Clinicians, the report revealed that the median age when people are diagnosed with colorectal cancer was 72 in 1989 until the early 2000s but it went down to 66 by 2016.
This means that half of all new diagnoses are in people 66 years old and younger. The researchers also discovered that the rate at which people are diagnosed with colorectal cancer in the US is falling among those 65 and older but increasing in younger adults.
Results of the study
Rebecca Siegel, study co-author and scientific director of surveillance research at the American Cancer Society in Atlanta, pointed out that scientists have already known about the increasing number of cases of colorectal cancer in younger age groups, “but we were surprised by how fast it is happening.”
Siegel said: “This report is very important because it not only provides a snapshot of the current colorectal cancer burden, but also a window to the future.”
She also emphasized that if the increases in younger adults continue, “doctors should be aware of the unique challenges in this patient population — such as the need for the preservation of fertility and sexual function, as well as the risk of long-term treatment effects because of their extended life expectancy.”
The researchers used data on colorectal cancer incidence and deaths from the National Cancer Institute and the US Centers for Disease Control and Prevention.
Data analysis indicated that colorectal cancer incidence among adults younger than 50 has been increasing since the mid-1990s and from 2012 to 2016, incidence rates among that age group went up by 2.2% annually and included tumors found in both the colon and the rectum.
They also discovered that during the 2000s, colorectal cancer incidence among adults ages 50 to 64 declined but this trend reversed and then increased by 1% annually between 2011 and 2016.
Meanwhile, colorectal cancer incidence rapidly declined in the 2000s among adults ages 65 and older and rates fell by 3.3% yearly from 2011 to 2016.
Siegel said: “Much of the decline in incidence in older aged adults is because of increased screening, but the cause for rising incidence in younger age groups is still unknown. The obesity epidemic is probably contributing, but doesn’t seem to be the sole cause.”
“Diet has a large influence on colorectal cancer risk and there is a lot of research going on looking at how different things we consume, including drugs such as antibiotics, influence gut health, specifically their role in determining the microorganisms that make up our microbiome,” she added.
Trend to continue
Dr. Kimmie Ng, a medical oncologist and director of the Young-Onset Colorectal Cancer Center at Dana-Farber/Brigham and Women’s Cancer Center in Boston, who was not involved in the analysis, pointed out that the report reinforces that the rise in colorectal cancer among younger adults “is in fact real.”
Dr. Ng said: “There does seem to be this very concerning steady rise in the incidence of colorectal cancer in younger individuals, which is not an isolated phenomenon. It’s actually expected to continue.”
She added that environmental factors and changes in gut health could be factors but said: “It is honestly the question that keeps me up at night because it really right now is a mystery.”
She emphasized the importance for younger adults to be aware of this rise in colorectal cancer rates and to talk to their doctors if they have any questions or notice signs or symptoms.