New research released by The University of Texas MD Anderson Cancer Center (TX, USA) indicates that within the next 15 years, more than one in ten colon cancers and nearly one in four rectal cancers will be diagnosed in patients younger than the traditional screening age. In addition to this, data trends among individuals aged 20–34 years in the US suggest that the incidence of colon and rectal cancer (CRC) is expected to increase by 90% and 124.2%, respectively, by 2030.
Published in the current issue of JAMA Surgery, the team’s findings build on previous studies of CRC trends by providing quantitative estimates of the exponentially increasing risk of CRC in patients under the conventional screening age of 50.
“This is an important moment in cancer prevention,” commented principal investigator George J Chang (University of Texas). “We’re observing the potential real impact of CRC among young people if no changes are made in public education and prevention efforts. This is the moment to reverse this alarming trend.”
The retrospective cohort study analyzed Surveillance, Epidemiology, and End Results data on more than 393,000 patients with histologically confirmed CRC from 1975 to 2010, examining age at diagnosis in 15-year intervals beginning at the age of 20 years.
The study results confirmed that the annual incidence rate for CRC diagnosed in patients under the age of 34 years is increasing at all stages of the disease; these include localized (confined to the colon or rectum), regional (contiguous and adjacent organ spread) and distant (remote metastases) spread.
The researchers hypothesize that the predicted increases in CRC risk in younger patients could be linked to lifestyle factors such as obesity and the Western diet, as well as lack of exercise.
In contrast to the increase in CRC risk in younger patients, there has been a steady decline in the incidence rate of CRC in patients over 50 years of age, most notably in regional and distant disease. This trend is also predicted to continue, with incidence decreasing by 21.2% and 37.8% in 2020 and 2030 for colon, respectively; and 19.0% and 34.3% in 2020 and 2030 for rectum, respectively.
While the researchers note that these findings do not yet warrant revisiting screening methodologies, the study’s first author Christina E Bailey (MD Anderson Cancer Center) added that physicians should be conscious of CRC symptoms in younger individuals, which would only usually be identified as cancer after the disease has progressed further.
“While our study observations are limited to CRC, similar concerns are being raised about breast cancer, as we see incidence increasing among younger women,” explained Chang. “Identifying these patterns is a crucial first step toward initiating important shifts in cancer prevention.”