The rise in cancer rates among young people is alarming. The primary suspects: food, pollution, and microplastics.
Drafted on September 3, updated on December 30, 2024
The rise in cancer rates among young people is prompting a search for the environmental culprit.
The fact that many of these cancers are gastrointestinal in nature offers clues and could point to microplastics.
Compiled by Ahujana Ahuja, scientific commentator.
The notion of cancer as a predominantly elderly disease is beginning to crumble. An analysis from last year showed that, within the G20 group of industrialized nations, the rates of several cancers are increasing more rapidly among the young than among the elderly. Now, scientists at the American Cancer Society have confirmed this trend across a broader range of cancers, with statistics strongly suggesting that a person from Generation Z or a Millennial is more likely to develop certain types of cancer than their Baby Boomer parents.
Half of the 34 cancer types studied exhibited a “birth cohort effect,” meaning they are increasingly common among younger successive cohorts. For instance, the incidence rate for pancreatic and kidney cancer among those born in 1990 was two to three times that of individuals born in 1955.
The academics who published their findings in Lancet Public Health last week refer to these changes as “generational shifts in cancer risk.” These changes have far-reaching implications. A surge in younger patients poses a challenge for future cancer care, whether it involves rethinking screening programs or finding ways to preserve fertility during treatment. As the disease itself transforms into something unfamiliar, the dream of consigning it to history becomes ever more daunting.
Hyuna Sung, an epidemiologist at the ACS in Atlanta, collaborated with colleagues to delve into data from the American cancer registry covering over 23 million individuals diagnosed with 34 different types of cancer between 2000 and 2019. The researchers also tapped into registries documenting over 7 million deaths from 24 cancer types during the same period. The data were organized by birth year, with patients grouped in five-year intervals from 1920 to 1990. Previous research by the ACS and other groups found evidence of several cancers—including colorectal (or intestinal), pancreatic, kidney, gallbladder, and testicular—rising among those under 50. Sung and her colleagues uncovered the same pattern on an even larger scale. Among the emerging conditions trending upward in younger generations are small intestine cancers, liver cancer in women, and anal cancer in men. In some cases, mortality rates have also risen, including for colorectal, liver (in women), and testicular cancers.
“These sober results make you reflect, as they indicate that the increase in cancer risk among younger generations is not merely an artifact of more frequent diagnoses,” Sung told me. “Instead, they point to a genuine rise in population-level cancer risk, with the increase in incidence being substantial enough to overcome the gains made in cancer survival.”
The fact that many of the cancers afflicting younger patients are gastrointestinal—involving the bile duct, liver, and gallbladder—might offer further clues. Jeffrey Meyerhardt, head of clinical research at Harvard University’s Dana-Farber Cancer Institute, which recently opened a clinic focused on under-50 colorectal cancer patients, notes that while there are likely unidentified risk factors, known risks such as sedentary lifestyles, dietary changes, and rising rates of obesity and diabetes also play a role.
These same factors might disrupt the gut microbiome, the delicate balance of internal bacteria thought to influence health and immunity. “But exactly what these changes [in the microbiome] are, and how to reverse or improve them, remains unknown,” Meyerhardt explained. Many of the young patients at the new clinic are in good shape, exercise regularly, and eat healthily. This is driving a hunt for environmental carcinogens capable of affecting entire generations.
Last year, New Zealand researchers demonstrated that microplastics—now found everywhere and ingested from childhood onward—might disrupt the intestinal lining. The prevalence of microplastic pollution since the 1960s—tiny plastic particles originating from consumer products and industrial waste breakdown—fits the timeline and could explain the generational cohort effect, although further investigation is needed.
In the meantime, screening programs are evolving: in the United States, a task force has recommended that breast cancer screening begin a decade earlier, at 40 years old; yet experts are hesitant to adopt a similar approach for colorectal cancer, as there is still a lack of screening protocols for individuals in their twenties and thirties. These decisions are delicate. More extensive screening brings disadvantages: costs, radiation exposure, and false positives. Moreover, those over 50 still account for 90% of cancer cases. Nevertheless, the shifting weight of the disease now warrants closer political attention.
Confirmation has come from French sources that cite the same study while better articulating the reasons for the rise in cases among young people: in the United States, many cancers are becoming more common among the young. According to a large American study, those born in the ’80s and ’90s are more likely to develop cancer than their older counterparts. The rise in these diseases is therefore not solely attributable to an aging population. The incidence of tobacco-related cancers is decreasing, in contrast to cancers linked to pollution and diet.
I was already aware of this situation, as it had been reported by the AIRC Foundation (the Italian association for cancer research [*]), but the data from this study compel us, as a Foundation, to pursue further research, particularly regarding junk food and microplastics.
On the topic, please also read: Microplastic Pollution: “increased risk of soil contamination in areas subject to human intervention compared to natural areas” (within the article, there is a link to all the banned substances, or you can read it here).
