A major study has found that younger generations face a greater risk of developing 17 certain cancers compared to older people, with researchers saying increasing cancer rates could reverse “decades of progress” against the disease.
Cancer rates have continued to rise in successively younger generations, with the research showing those most at risk are Generation X – those born in the U.S. between 1965 and 1980 – and millennials – those born between 1981 to 1996.
The 17 cancer types they are more at risk of developing include breast, pancreatic, and gastric cancers, while death rates have also risen in conjunction with rates of liver (female only), uterine corpus, gallbladder, testicular, and colorectal cancers.
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Senior study author Dr Ahmedin Jemal, from 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.”
The research team analysed data from 23.6 million patients diagnosed with 34 types of cancer and mortality data from 7.3 million deaths for 25 types of cancer for individuals aged from 25 to 84 years over the period January 2000 to December 2019.
They compared birth cohorts, using birth years separated by five-year intervals, from 1920 to 1990.
The researchers found that cancer rates increased with each successive birth cohort born since approximately 1920 for eight of 34 cancers.
Concerningly, the incidence rate was around two to three times higher in the 1990 birth cohort compared to the 1955 birth cohort for pancreatic, kidney, and small intestinal cancers in both male and females; and for liver cancer in females.
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Across all cancer types, rates in the 1990 birth cohort ranged from 12% higher for ovarian cancer to 169% higher for uterine corpus cancer compared to the rate in the birth cohort with the lowest cancer rates.
Lead study author Dr Hyuna Sung, from 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.”
Lisa Lacasse, president of the American Cancer Society Cancer Action Network, added: “The increasing cancer burden among younger generations underscores the importance of ensuring people of all ages have access to affordable, comprehensive health insurance, a key factor in cancer outcomes.”
Read the study in full in The Lancet Public Health.
