Millennial and Gen X are developing 17 types of cancers far more frequently than older generations, study finds

India is already grappling with a significant cancer burden, having recorded about 12 lakh new cancer cases and 9.3 lakh cancer deaths in 2019. Even as the healthcare struggle continues, new research has shed light on an emerging crisis.

Analysing data from over 23 million US cancer patients diagnosed between 2000 and 2019, the study found that cancer incidence rates have surged among younger generations for 17 out of 34 cancer types, such as breast, pancreatic, and gastric cancers.

Younger populations more prone

In particular, people born in 1990 have notably higher rates of pancreatic, kidney, and small intestinal cancers compared to those born in 1955. Women in particular are seeing higher rates of liver cancer. Mortality rates are also on the rise for liver cancer (in women), uterine corpus, gallbladder, testicular, and colorectal cancers.

The analysis showed that incidence rates have risen with each successive birth cohort since around 1920 for eight types of cancer. The incidence rate for the 1990 birth cohort is approximately two-to-three times higher than for the 1955 birth cohort for pancreatic, kidney, and small intestinal cancers in both men and women, and for liver cancer in women.
Furthermore, incidence rates increased in younger cohorts after a decline in older ones for nine cancers, including oestrogen-receptor-positive breast cancer, uterine corpus cancer, colorectal cancer, non-cardia gastric cancer, gallbladder cancer, ovarian cancer, testicular cancer, anal cancer in men, and Kaposi sarcoma in men.

Across various cancer types, the incidence rate in the 1990 birth cohort ranged from 12% higher for ovarian cancer to 169% higher for uterine corpus cancer compared to the birth cohort with the lowest incidence rate. Mortality rates also increased in younger cohorts for liver cancer (female only), uterine corpus, gallbladder, testicular, and colorectal cancers.

Differing socioeconomic factors to blame

The study’s lead author, Dr Hyuna Sung, emphasised that these increases may be linked to unique social, economic, and environmental factors faced by different birth cohorts during their developmental years. However, the precise reasons for these rising rates remain unclear.

If this trend is representative for the rest of the world, it is epecially alarming for India, where the cancer burden is already projected to increase to 29.8 million disability-adjusted life years by 2025. Many experts have blamed factors such as lifestyle changes, increased consumption of processed foods, tobacco use, and environmental pollution for this growing problem,
“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,” notes another study author Dr Ahmedin Jemal. “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,” added.”

The findings of this research have been published in The Lancet Public Health and can be accessed here.