Millennials, Gen Xers face higher risk of 17 cancers than previous generations, study says

FILE - Chemotherapy drugs on hospital IV pole. (Photo by: GHI/Education Images/Universal Images Group via Getty Images)

Gen Xers and Millennials face a higher risk of developing certain types of cancers compared to earlier generations, according to a newly published study.

The study, published Wednesday in the journal The Lancet Public Health, suggests that younger generations have a higher risk of getting 17 of the 34 cancer types, including breast, pancreatic, and gastric cancers. 

"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," Dr. Hyuna Sung, lead author of the study and a senior principal scientist at the American Cancer Society, said in a statement. 

The findings highlight "the critical need to identify and address underlying risk factors in Gen X and Millennial populations" in an effort to develop better prevention strategies, the study authors said.

The study was led by researchers at the American Cancer Society and included data from nearly 24 million patients diagnosed with 34 types of cancer between Jan. 1, 2000, and Dec. 31, 2019. It also looked at mortality data from 7.3 million deaths for 25 types of cancer for individuals during the same period.

The patients were all between the ages of 25 and 84.

"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," Sung added.

"Although we have identified cancer trends associated with birth years, we don’t yet have a clear explanation for why these rates are rising," Sung continued.

Researchers found that cancer incidence rates increased with each birth cohort born since roughly 1920 for eight of 34 cancers. 

Specifically, the incidence rate was approximately "two-to-three times higher" in the 1990 birth cohort than in the 1955 birth cohort for pancreatic, kidney, and small intestinal cancers in both male and female patients, according to the study. This was also the case for liver cancer in females.

Across cancer types, the incidence rate in the 1990 birth cohort ranged from 12% for ovarian cancer, to 169% higher than the birth cohort with the lowest rate for uterine corpus cancer, according to the study.

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"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," said Dr. Ahmedin Jemal, senior vice president of surveillance and health equity science at the American Cancer Society and senior author of the study.

"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," Ahmedin added.

This story was reported from Cincinnati.