Newer generations are at a greater risk of more than a dozen cancers than those that came before them, a major study suggests.
An analysis of tens of millions of diagnoses found millennials (born between 1986-95) and Generation X (1965-85) were more likely to develop 17 forms of cancer than the post World War II Boomer generation.
Included in the 17 are some of the most deadly types of cancer, such as colon cancer and pancreatic and liver cancers.
Obesity and binge drinking are thought to be partly fueling the crisis, though experts are still largely unsure what else is behind the rise.
The rise among new generations threaten to reverse decades of progress fighting the disease. Diagnoses are expected to nearly double from 2020 to 2050 and there are signs death rates are beginning to plateau.
About 20 million cases of cancer were diagnosed in 2022, but that number is projected to balloon to more than 35 million cases by 2050
Experts also say the increasing cancer burden will prevent them from contributing to the US economy, causing higher unemployment and slower growth and sending healthcare costs spiraling.
That could spark a vicious cycle where poorer health causes economic struggles, contributing to even worse health from lack of access to treatment.
Dr Ahmedin Jemal, senior study author and senior vice president of surveillance and health equity science at the American Cancer Society, said: ‘The increase in cancer rates among this younger group of people indicate generational shifts in cancer risk and often serve as an early indicator of future cancer burden in the country.’
‘Without effective population-level interventions, and as the elevated risk in younger generations is carried over as individuals age, an overall increase in cancer burden could occur in the future, halting or reversing decades of progress against the disease.’
‘The data highlights the critical need to identify and address underlying risk factors in Gen X and Millennial populations to inform prevention strategies,’ he added.
The findings come amid a worrying rise of colorectal cancer in Americans under 50
Researchers from the ACS analyzed data from more than 23million patients diagnosed with 34 forms of cancer in a 20-year period. Patients ranged from 25 to 84 years old.
The patients were then divided into cohorts based on their birth years, from 1920 to 1990.
Gen X and millennials were up to three times more likely to develop several forms of cancer than Boomers. These included forms like colorectal cancer, which has been quickly rising in adults under 50.
And as cancer rates declined among older people, incidences in younger patients increased for nine cancers, including breast, uterine, colorectal, ovarian, and testicular cancers.
The finding is in line with other nationwide data warning against an increase in cancer among younger adults.
While part of the rise could be due to increased testing and patients getting better at spotting the disease, the new study shows that increasing lifestyle factors like obesity and drinking could be partly to blame.
The researchers stated that among adults ages 25 to 49, ‘the most rapid increases in incidence rates’ were seen with pancreatic, small intestine, and kidney and pelvis cancers, which are all linked to obesity and alcohol.
Mortality rates also increased among younger patients for liver, uterine, gallbladder, testicular, and colorectal cancers.
Dr Hyuna Sung, lead study author and senior principal scientist of surveillance and health equity science at the American Cancer Society, said: ‘These findings add to growing evidence of increased cancer risk in post-Baby Boomer generations, expanding on previous findings of early-onset colorectal cancer and a few obesity-associated cancers to encompass a broader range of cancer types.’
‘Birth cohorts, groups of people classified by their birth year, share unique social, economic, political, and climate environments, which affect their exposure to cancer risk factors during their crucial developmental years.’
‘Although we have identified cancer trends associated with birth years, we don’t yet have a clear explanation for why these rates are rising.’
CDC data shows the top cancer death hotspots, with Mississippi ranking the highest with 985 deaths per 100,000 people
Though the team found no direct cause for these increases, they speculated that obesity could be a major driver in colorectal, uterine, gallbladder, kidney, and pancreatic cancers.
CDC data published last year, for instance, found that 40 percent of Americans are now obese, meaning they have a body mass index (BMI) of 30 or more. And 30 US states saw increases in obesity from the year before.
Additionally, the team noted that an increase in binge drinking could be to blame for liver cancer, which is largely caused by alcoholism.
According to the latest CDC data, for example, the amount of adults who report binge drinking increased 12 percent between 2011 and 2017.
While the study covered a wide range of cases, it still had some limitations, including some data being missing from cancer registries and some cancers being misidentified.
The findings were published Wednesday in The Lancet Public Health.