Study shows ‘dramatic’ increase in early onset cancers

Editor's Note

In this study conducted by researchers from Brigham and Women’s Hospital, titled “Is early- onset cancer an emerging global epidemic? Current evidence and future implications” and published by Nature Reviews Clinical Oncology, the incidence of early onset cancers (cancer diagnosed before age 50), including breast, colon, esophagus, kidney, liver, and pancreas cancer, among others, has “dramatically increased around the world, with this drastic rise beginning around 1990,” Healthcare Purchasing News September 8 reports.

The study first analyzed global data describing the incidence of 14 different cancer types that showed increased incidence in adults before age 50 from 2000 to 2012. The researchers then searched for available studies that examined trends of possible risk factors including early life exposures in the general population, before they examined the literature describing clinical and biological tumor characteristics of early-onset cancers compared to later-onset cancers diagnosed after age 50.

The analysis found that the early life exposome, which encompasses diet, lifestyle, weight, environmental exposures, and microbiome, has changed substantially in the last several decades. Possible risk factors that the researchers speculate has accompanied altered microbiome for early-onset cancer include alcohol consumption, sleep deprivation, smoking, obesity, and eating highly processed foods.

“From our data, we observed something called the birth cohort effect. This effect shows that each successive group of people born at a later time (eg, decade-later) have a higher risk of developing cancer later in life, likely due to risk factors they were exposed to at a young age,” said Shuji Ogino, MD, PhD, a professor and physician-scientist in the Department of Pathology at Brigham. “We found that this risk is increasing with each generation. For instance, people born in 1960 experienced higher cancer risk before they turn 50 than people born in 1950 and we predict that this risk level will continue to climb in successive generations.”

The researchers acknowledged that this increased incidence of certain cancer types is, in part, due to early detection through cancer screening programs but could not precisely measure what proportion of this growing prevalence could solely be attributed to screening and early detection.