A new study conducted by researchers at the American Cancer Society has found that Generation X (Gen X) and millennials are at a higher risk of developing 17 cancers compared to older generations. For the study, published in the journal The Lancet Public Health, researchers analysed data on more than 23 million patients diagnosed with 34 types of cancer and more than 7 million people who died of 25 types of cancer. The data included adults ages 25 to 84 from 2000 to 2019. The researchers calculated cancer incidence rates and cancer death rates by birth years, separated by five-year intervals, from 1920 to 1990.
The researchers found that the incidence rate for small intestine, kidney and pancreatic cancers was two to three times higher for people born in the early 1990s than in the late 1950s. They also found that women born in the late '50s also fared better than their millennial counterparts with regard to liver cancer and oral and throat cancers caused by factors other than human papillomavirus.
"Uterine cancer is one that really jumps out where we see tremendous increases. It has about a 169% higher incidence rate if you're born in the 1990s as opposed to if you're born in the 1950s - and this is for people at the same age. Someone born in the 1950s, when they were in their 30s or 40s, saw a different incidence rate compared with someone born in the 1990s in their 30s or 40s," said Dr William Dahut, chief scientific officer for the American Cancer Society, whose colleagues authored the new study.
"What's a little different about this paper is that it includes a wider variety of cancers," he said. "It actually looked at 34 different cancers in which 17, we saw an increase in incidence, and five an increase in mortality in young adults under the age of 50," he added.
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Notably, those 17 cancers include gastric cardia, small intestine, estrogen receptor-positive breast, ovary, liver and intrahepatic bile duct in women, non-HPV-associated oral and pharynx cancers in women, anus, colon and rectal, uterine corpus, gallbladder and other biliary, kidney and renal pelvis, pancreas, myeloma, non-cardia gastric, testis, leukemia and lastly, Kaposi sarcoma, which affects the lining of blood vessels and lymph vessels, in men.
The researchers found that 10 of the 17 cancers with increasing incidence in younger birth cohorts are related to obesity. The researchers also found that cancer death rates increased in successively younger generations alongside incidence rates for liver cancer among women, uterine corpus, gallbladder, testicular, and colon and rectal cancers.
"The data highlights the critical need to identify and address underlying risk factors in Gen X and millennial populations to inform prevention strategies," said senior study author Dr Ahmedin Jemal, ACS senior vice president, surveillance and health equity science.
