Clinicians are increasingly diagnosing cancers such as breast, colorectal, and gastrointestinal malignancies in adults under the age of 50. Older individuals still account for the majority of cancer cases, but the growing incidence of early-onset disease has sparked an important question: why are more young adults being diagnosed? A widely cited global analysis published in BMJ Oncology found that early-onset cancer incidence rose by nearly 79 per cent worldwide between 1990 and 2019, a trend large enough that it can no longer be dismissed as a statistical anomaly.
The answer is unlikely to lie in a single factor. Genetics can significantly increase cancer risk in some individuals, but lifestyle changes, obesity, environmental exposures, and improved detection are also reshaping the cancer landscape. Understanding how these factors interact matters not just scientifically; it is central to how we, as a diagnostics industry, should be designing screening and testing pathways. Identifying who is at higher risk, and doing so early, is what enables timely intervention and genuinely personalised care rather than reactive treatment after the fact.
A fast-forwarded timeline
Cancer results from a combination of genetic predisposition, acquired genetic mutations, lifestyle habits, environmental exposures and ageing. At the cellular level, these factors change DNA in ways that disrupt normal cell growth and repair. In older adults, such changes typically accumulate gradually over decades. When cancer occurs in a younger individual, however, it suggests that inherited genetic factors, early-life exposures, or other biological influences may have accelerated that process, which is exactly why understanding the underlying cause, not just the diagnosis, is so important.
Inherited blueprints vs. modern triggers
The evidence is clear that inherited cancer risk, passed down through families, shows up far more often in younger patients than in older generations. In early-onset cases, a meaningfully higher proportion of individuals carry specific genetic markers, BRCA1 and BRCA2 mutations for breast and ovarian cancer, or Lynch syndrome markers for colorectal cancer, among others. For these individuals, their genetic blueprint effectively fast-forwards the disease timeline.
Yet family history alone does not explain the entire surge. It is a complex interplay of inherited vulnerability and modern lifestyle factors. Metropolis offers a wide range of tests curated to detect hereditary cancers and pairs them with expert genetic counselling, so a young patient with a strong family history gets both a result and someone qualified to explain what it means for them and their relatives.
Shifting focus to early detection
Fortunately, this challenge arrives at a time when the diagnostic toolkit is more advanced than it has ever been. Next-Generation Sequencing (NGS) has transformed what a laboratory can do. Instead of testing one gene at a time, comprehensive genetic panels can now scan hundreds of risk markers simultaneously, letting doctors identify a person's high-risk status well before physical symptoms surface.
Addressing the rise of cancer in young adults means moving from traditional, reactive treatment toward proactive screening. When a young individual shows unusual symptoms or has a strong family history, timely genomic testing is not optional; it is the fastest route to clarity. Mapping a person's genetic profile provides the information needed to catch disease early and, in the cases where it matters most, to turn the tide.
Metropolis offers a comprehensive solution in this field through its Centre of Genomics, assisted by a complete menu in oncology, neurology, transplant immunology, and rare disease diagnostics.
The author is the chief scientific and innovation officer at Metropolis Healthcare Limited.
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.
