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Aussies in their 30s and 40s are being diagnosed with cancer at unprecedented rates
Australians in their 30s and 40s are being diagnosed with cancer at unprecedented rates, with at least 10 types of the disease on the rise.
The worrying phenomenon, known as early onset cancer, is drawing increasing concern from experts who say the trend is steep, widespread, and in many cases, not fully understood.
New figures from Cancer Australia, the federal government's cancer agency, reveal staggering increases between 2000 and 2024.
Among 30 to 39-year-olds, rates of prostate cancer have climbed by 500 per cent, pancreatic cancer by 200 per cent, liver cancer by 150 per cent, uterine cancer by 138 per cent, and kidney cancer by 85 per cent.
While changes in diagnostic techniques may partially account for the growth in some cancers, such as prostate, most of the rise appears to defy such explanation.
Professor Dorothy Keefe, the chief executive of Cancer Australia, told the ABC's Dr Norman Swan that approximately 10 types of cancer are now showing significantly elevated rates in young adults.
She says that cancer has traditionally been a disease of ageing, with common forms such as bowel, breast, and lung cancer typically becoming more prevalent in older populations.
And Australia isn't alone in facing this challenge.
Data from cancer registries in the United States show a similarly dramatic rise in early onset cancers.
Dr Philip Rosenberg, a recently retired biostatistician from the US National Cancer Institute, has observed clear generational differences when comparing Generation X to the Baby Boomers.
He said the most notable increases have occurred in cancers of the colon, rectum, thyroid, pancreas, prostate (in men), and oestrogen receptor-positive breast cancer (in women). According to Dr Rosenberg, around half of all cancer types now show some generational shift in incidence.
Bowel cancer is of particular concern in Australia, where rates among 30 to 39-year-olds have increased by 173 per cent since the year 2000.
Even more troubling is the fact that diagnoses in this age group often come at a later stage, when the disease is more advanced and harder to treat.
Despite decades of research, the causes of cancer remain complex and elusive.
All cancers are caused by changes in genes, but not all of these changes are inherited. In well-known hereditary cases such as the BRCA mutations linked to breast and ovarian cancer, or Lynch Syndrome associated with bowel cancer, a clear genetic pathway is evident. However, most young people affected by early onset cancer do not carry these mutations.
Instead, many scientists believe that environmental factors — or the 'exposome' — could be playing a role.
These are external influences that interact with a person's genes to trigger malignant changes.
The key may lie in understanding the environment that today's 30- and 40-year-olds were exposed to as children or even in utero, particularly between the 1960s and 1990s.
During those decades, the Western world experienced major societal shifts.
Childhood obesity began to rise, diets became more reliant on ultra-processed foods, and antibiotics were more commonly prescribed. Caesarean section rates also increased, potentially disrupting the transfer of microbiomes from mother to child — a factor that could affect immune system development.
Microplastics still the great unknown
Compounding the concerns is the growing presence of synthetic chemicals and plastics in everyday life.
Despite being a new area of research, some scientists have warned that microplastics can have harmful effects on the human body, especially in large concentrations.
In 2022, microplastics were detected in human blood for the first time, sparking a flurry of new research.
As the name suggests, microplastics are small plastic particles, less than 5mm in diameter, and are reported to be near ubiquitous: they have been found in drinking water, food, and the atmosphere.
A University of Newcastle report commissioned by the World Wide Fund for Nature found that the average individual could be ingesting as much as 5 grams, or 1 credit card's worth of microplastics every week.
The WHO said in 2019 that the most immediate risk to human health could be from the toxicity of some microplastics, which may be from the production process itself or toxic substances the particles pick up from the environment.
'Further research is needed to obtain a more accurate assessment of exposure to microplastics and their potential human health,' said Dr Maria Neira, director of the WHO's department of public health, environment, and social determinants of health said at the time.
