Colorectal cancer rates have been increasing in recent years for Americans below the age of 55, and scientists are unsure why. In addition, a new study finds that deaths from colorectal cancer have also jumped in the same age group.
Researchers say these findings are troubling because this means the increase in colorectal cancer diagnoses are not just because of more screening and colonoscopies, CBS News reports. Rebecca Siegel, strategic director of surveillance information services at the American Cancer Society and lead author on the study, said, “This is not good news. We looked at adults from ages 20 to 54 and following several decades of pretty rapid declines in death rates, over the past decade deaths in this age group have been increasing.” She added, “This indicates that there’s actually a true increase in disease. It’s not just detection of disease that was there and that we’re catching it earlier.”
This surge in colorectal cancer deaths was particularly surprising since, for decades, screening has been recommended for those 50 years old and up.
The researchers used data from the National Center for Health Statistics to analyze colorectal cancer deaths in people ages 20 to 54 from 1970 to 2014. There were over 242,000 deaths due to this cancer in that time frame.
Another interesting find was that the growing trend is being driven by colorectal cancer deaths in white men and women. The rate among African-Americans has declined.
Mortality rates for colorectal cancer deaths in adults 20 to 54 years of age went down from 6.3 per 100,000 in 1970 t0 3.9 per 100,000 in 2004. Then the numbers started going up again, reaching 4.3 per 100,000 individuals in 2014.
Siegel notes that the findings are surprising because they appear to be inconsistent with trends for major risk factors in colorectal cancer, such as obesity. She said, “The thinking has been that the reason we’re seeing the increase in this disease is because of the excess body weight we’ve been dealing with for the past several decades, but the obesity epidemic has affected everyone universally across races and ethnicities and if anything the increase in obesity in the black population has been higher.”
Why this is so is unclear, Siegel said.
The answer is that no one really knows why this is happening.
Researchers are looking into the matter, but many experts believe that the answer may lie partly in the microbiome, or the bacteria that normally live in the human body. Siegel said, “I think we’re going to need more time for etiologic studies to try to understand this.”
The important thing for now is to catch the cancer early on. If caught and treated in the early stages, treatment results work an estimated 50% of the time, according to the National Cancer Institute.
The study was published in the Journal of the American Medical Association.