During that time, overall death rates from colon cancer dropped from about 6 to about 4 per 100,000 population.
Researchers said the increase colorectal cancer deaths in people in their 50s was particularly unexpected since screening - which can both prevent colon cancer and detect it early - has been recommended starting at age 50 for decades.
Death rates from colon cancer are on the rise among younger, white Americans and doctors are desperately trying to figure out why. CRC mortality overall is declining rapidly, masking trends in young adults, which have not been comprehensively examined.
Among other races combined, mortality rates declined from 1970 through 2006, then stabilized through 2014.
According to the newly published report, death rates from colorectal cancer among White people in the aforementioned age group are rising by 1 per cent each year.
"This indicates that the increase in incidence is not exclusively 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.
She said the findings were sobering, adding that "educational campaigns are needed to alert clinicians and the general public about this increase to help reduce delays in diagnosis, which are so prevalent in young people, but also to encourage healthier eating and more active lifestyles to try to reverse this trend".
Using data from the National Center for Health Statistics, the researchers analyzed colorectal cancer deaths in people aged 20 to 54 from 1970 through 2014. The increase was confined to white individuals, among whom mortality rates increased by 1.4 percent per year, from 3.6 in 2004 to 4.1 in 2014.
"We do not have an answer for why colorectal cancer is increasing in whites but not in blacks".
The five-year survival rate between institutions "changes significantly depending on factors such as the number of patients with advanced cancer", the center's officials said. There were over 242,000 deaths due to this cancer in that time frame. The authors note that these disparate racial patterns are inconsistent with trends in major risk factors for colorectal cancer like obesity, which is universally increasing.
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. These include rectal bleeding and a change in bowel habits.
Follow guidelines for screening. Right now, doctors recommend getting a colonoscopy at age 50 and repeating every 10 years until age 75 if you have no risk factors.
The latest survey on the five-year survival rate, which shows how likely it is that patients diagnosed with cancer will be alive at the end of that period, excludes those who died of other causes. The researchers report no relevant financial disclosures.