Obesity-Related Cancers Are Rising in Young and Old

Increases in early-onset cancer might be a sign of growing cancer rates across all adult age groups.

Clinicians and scientists have recently observed a considerable rise in early-onset cancers in individuals under the age of 50.¹ Concerningly, this phenomenon exists for a wide range of cancers and can be found in multiple countries, causing some to wonder if this was an emerging epidemic.¹ A new international comparative study, published in the journal Annals of Internal Medicine, showed that increased rates for certain cancers are not only unique to younger individuals but can also be found in older adults. Moreover, they found that the cancers in both age groups showing the highest increases in prevalence were linked to obesity.²

Cancer has been long considered a disease of the elderly, manifesting as the consequence of accumulating DNA damage over time.^3,4 As such, the recent sharp increase in early-onset cancers has received a lot of attention, with scientists, advocates, and the public rightfully concerned about the possibility of new carcinogens.^2,5 However, this has overshadowed the fact that older individuals continued to make up the majority of new cancer cases worldwide, with few looking to ask: Is the observed rise in early-onset cancers just a component of a bigger trend affecting all age groups?⁵

A research team from the UK-based Institute of Cancer Research, London, headed by clinical epidemiologist Amy Berrington de Gonzalez, sought to answer this very question. Harnessing data from the International Agency for Research on Cancer Global Cancer Observatory database, she and her team looked at the incidence of 13 cancer types in young (aged 20-49) and old adults (aged 50+) from 42 different countries between 2003-2017. When choosing which cancers to evaluate, Berrington and her colleagues specifically selected cancers reported to be globally on the rise in younger adults between 2002-2012.

Six of the selected cancers—leukemia, thyroid, breast, colorectal, kidney, and endometrial—increased in prevalence in young adults in at least 75 percent of the examined countries. However, five of these six cancers also showed increased prevalence in older adults. Colorectal cancer was the exception. Berrington’s team found increased early-onset colorectal cancer incidence in 88 percent of the investigated countries, compared to only 55 percent for older adults. Furthermore, the increases in younger adults were greater than the increases in older adults for 69 percent of countries. Berrington hypothesized that this could be due to improved detection, as the biggest differences in colorectal cancer rate were found in countries with widespread screening in older adults— the US, Canada, Australia, New Zealand, the UK, Austria, and Switzerland.

Finally, Berrington and her colleagues noticed that the cancer types with increased incidence in both younger and older adults were all linked to obesity—a trend that is in line with previous studies and increasing obesity rates in youths, adolescents, and adults.^6-8

“This analysis demonstrates an increase in cancer burden across the adult age spectrum. Therefore, the contemporary concern about increasing cancer rates should recognize that this increase is not restricted to young adults but affects all generations,” opined Efrat Dotan in an editorial, an oncologist at Penn Medicine Lancaster General Hospital, who was not affiliated with this study.⁵ “Furthermore, it calls for consideration of the future societal burden of a growing population of both younger and older adults faced with cancer.”