Why are so many young people seemingly getting cancer? It might down to early detection, study finds

Certain cancers that were once mostly diagnosed in older adults are now being identified more frequently in people under 50.

A US government study published earlier this year examined more than two million cases diagnosed in people aged 15 to 49 between 2010 and 2019.

Of 33 cancer types, 14 showed rising rates in at least one younger age group, with around 63 per cent of early-onset cases occurring in women.

However, experts from a new, separate study suggest that much of this increase may be due to overdiagnosis, rather than a true rise in deadly disease.

Published in JAMA Internal Medicine, researchers looked at the eight cancers with the fastest-rising incidence - thyroid, anus, kidney, small intestine, colorectal, endometrial, pancreas and myeloma - among adults under 50.

They found that while diagnoses of these cancers have roughly doubled since 1992, mortality rates have remained remarkably stable. This suggests that the rise in reported cases largely reflects increased detection and overdiagnosis, rather than a true surge in life-threatening disease.

For instance, thyroid and kidney cancers have seen dramatic increases in diagnosis without corresponding rises in deaths, indicating that many cases discovered may never have caused harm.

Similarly, early-stage breast cancers in women under 50 have risen, yet mortality has halved over the past three decades due to improvements in treatment rather than a worsening epidemic.

However, some exceptions exist. Colorectal and endometrial cancers have shown small but consistent increases in deaths, indicating a modest rise in clinically meaningful disease, likely linked to factors such as obesity and decreasing rates of hysterectomy.

For most other cancers studied, however, rising incidence appears largely a product of more sensitive detection methods, including screening, imaging, and incidental findings, rather than a true increase in dangerous cancers.

The authors of the study caution that framing early-onset cancer as an epidemic risks exaggerating the problem and may have unintended consequences. Unnecessary diagnoses can impose significant emotional, physical, and financial burdens on patients, subjecting otherwise healthy young adults to invasive treatments and long-term monitoring.