Why Is Cancer Affecting Younger and Younger People?
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An estimated 20 million cases of cancer were diagnosed worldwide in 2022, up from 18 million in 2020. Contrary to the often-proclaimed victory in the war on cancer, the number of cases will rise by 77% to 35 million by 2050, as recently predicted by the World Health Organization’s International Agency for Research on Cancer (IARC).
These trends are not only worrisome when looking 25 years ahead. The American Cancer Society (ACS) released its 2024 cancer forecast earlier this year. The organization anticipates new cancer diagnoses will surpass 2 million for the first time this year. This increase is particularly noted in four cancers for which early screenings exist: breast, prostate, colorectal and cervical cancers.
While the risk of dying from cancer in the U.S. has steadily declined over the years, thanks to remarkable advances in cancer detection and treatment as well as a reduction in smoking rates, diagnosis rates for certain types of cancer are increasing, particularly among younger segments of the population. And despite the success in identifying and treating cancer in older populations, there are some disturbing trends worldwide in who is affected by this ominous development.
These trends aren’t the same everywhere. Richer countries will likely see the biggest number of new cases, while poorer countries might struggle more because their health systems aren’t as strong – they could see cancer rates more than double.
“While these approaches will be lifesaving for millions, they also come with an ever-increasing financial burden and necessitate the expansion of the medical system.”
Scientists and the medical system are responding to these trends and projections with improving and lowering the threshold of various screening techniques (like endoscopic or molecular colorectal cancer screening) and identifying so called biomarkers that predict the development of a cancer, including advanced gut microbiome testing. While these approaches will be lifesaving for millions, they also come with an ever-increasing financial burden and necessitate the expansion of the medical system. In my view, the only way to deal with the projected trends is to identify the root causes of the problem (lifestyle and diet) and launching major public health and educational efforts for all segments of the US population to mitigate these factors.
Even though we’re getting better at finding and treating cancer early, there’s still a big gap in how well different places can handle it. While progress has been made in early cancer detection and treatment, significant disparities in cancer treatment outcomes exist not only between high- and low-income regions of the world, but also between high and low-income regions within countries. To deal with these disparities should be another major goal of the war on cancer.
When it comes to the types of cancer that are most common, even though lung and breast cancer remain at the top of the list globally, cancers of the digestive system, in particular of the colon and rectum, stomach, liver and the pancreas are part of the increase in cases, pointing towards the gut (and what we put into it) as a key player.
What is most concerning is that the average age of cancer patients is getting younger. Back in 1995, most people diagnosed with cancer were over 65. More people under 50 are getting diagnosed now compared to the past. Collectively, those under 50 were the only age group to see an increase in cancer diagnoses from 1995 through 2020.
“Now, [colorectal cancer] is the leading cause of cancer death for men in this age group, and the No. 2 cause for women.”
According to a recent article in the NYT by Erin Prater, colorectal cancer diagnoses, in particular, are trending upward among younger adults—those below the age of 50. “In the late 1990s, colorectal cancer was the fourth leading cause of cancer death among men and women in this age group. Now, it’s the leading cause of cancer death for men in this age group, and the number 2 cause for women. Scientists from the ACS speculate that lifestyle factors particularly common among those born in 1950 and later—like obesity, high consumption of ultra-processed foods, in particular red meat and alcohol, low levels of physical activity and fiber consumption, and smoking—are fueling this change.”
According to a study published by a group of Italian scientists in the Annals of Oncology, obesity and alcohol consumption are contributing to colorectal cancer’s rising death toll among young adults. This year, bowel cancer deaths among young people—Millennials and Gen Xers aged 25-49—are predicted to rise in some European countries for the first time, according to their report.
A total of 1.06 million under-50s died of cancer in 2019, an increase of 27% on the 1990 figure. After breast cancer, the highest death tolls were linked to windpipe, lung, stomach and bowel cancers.
“…the global number of new early-onset cancer cases and associated deaths will rise by a further 31% and 21% respectively by 2030, with people in their 40s the most at risk.”
The highest rates of early-onset cancers in 2019 were in North America, Oceania and western Europe. Low- and middle-income countries were also affected, and the highest death rates among under-50s were in Oceania, eastern Europe and central Asia. In low- and middle-income countries, early-onset cancer had a much greater impact on women than on men, in terms of poor health and deaths. Based on the observed trends for the past three decades, the researchers estimate that the global number of new early-onset cancer cases and associated deaths will rise by a further 31% and 21% respectively by 2030, with people in their 40s the most at risk.
“…so-called inflammatory diets along with high salt, alcohol and tobacco use, are considered the main risk factors…”
Even though genetic factors are likely to play a role in the changing pattern of cancer prevalence, lifestyle factors, in particular dietary habits may even play a bigger role. Diets high in ultra-processed foods, red meat, saturated fats and low in fruits and vegetables (so-called inflammatory diets) along with high salt, alcohol and tobacco use, are considered the main risk factors underlying the most common cancers among under-50s. The progressively increasing consumption of microplastics in our drinking water may be an additional factor, even though evidence for causality is currently not available. The data also indicates physical inactivity, excess weight and high blood sugar are contributory factors.
As I have discussed in detail The Mind Gut Immune Connection book and several previous posts, the same lifestyle and dietary factors not only play a major role in cancer prevalence, but have been implicated as major causes of the unfolding epidemic of chronic non-contagious diseases, including metabolic and neurodegenerative diseases. Evidence suggests that chronic low grade activation of the immune system is not only a key factor in this epidemic, but also plays a central role in the worrisome trends in cancer prevalence in younger and younger age groups.
Emeran Mayer, MD is a Distinguished Research Professor in the Departments of Medicine, Physiology and Psychiatry at the David Geffen School of Medicine at UCLA, the Executive Director of the G. Oppenheimer Center for Neurobiology of Stress and Resilience and the Founding Director of the Goodman-Luskin Microbiome Center at UCLA.