Early-onset lung cancer: why are more younger adults being diagnosed?
Published: 22 June 2026 | Reading time: 5 minutes
Lung cancer is often thought of as a disease that affects older people. However, researchers are increasingly paying attention to lung cancer diagnosed in younger adults.
This is sometimes called early-onset lung cancer.
There is no single definition, but the term is often used to describe lung cancer diagnosed before the age of 50.
Researchers do not yet have a complete explanation for why some people develop lung cancer at a younger age. However, several areas of research are beginning to provide clues.
What is early-onset lung cancer?
Most lung cancers are diagnosed in older adults.
When lung cancer develops at a younger age, researchers often describe it as early-onset lung cancer.
Although younger adults still account for a minority of cases, researchers have become increasingly interested in understanding why some people develop lung cancer decades earlier than expected.
A new study looks at biological ageing
A major study published in Nature Medicine on 22 June 2026 examined whether biological ageing could help explain rising rates of early-onset cancer.
The researchers analysed data from more than 150,000 people and found that accelerated biological ageing was associated with a higher risk of several early-onset cancers.
One of the strongest associations was seen in lung cancer.
The study also identified a link between immune ageing and early-onset lung cancer.
What is biological ageing?
Biological ageing is different from chronological age.
Chronological age is the number of years you have been alive.
Biological ageing refers to how old the body’s cells, tissues and systems appear based on measurements such as blood markers and other biological changes.
In this study, people who appeared biologically older than expected for their age were more likely to develop several early-onset cancers.
Is biological ageing the answer?
No.
The study does not show that biological ageing causes lung cancer.
Instead, it suggests biological ageing may be one factor among many that help explain why some people develop cancer at younger ages.
Researchers are continuing to investigate a wide range of possible influences.
Other questions researchers are exploring
Lung cancer in people who have never smoked
An increasing number of people diagnosed with lung cancer have never smoked.
Researchers are studying a range of possible influences, including environmental exposures, genetics and biological factors.
Lung cancer in women
Researchers have also been examining changing patterns of lung cancer in women, particularly among younger age groups and never-smokers.
Air pollution and environmental exposures
Air pollution remains an important area of investigation and is recognised as a cause of lung cancer.
Researchers continue to study how environmental exposures across a lifetime may contribute to risk.
Biomarkers and tumour biology
Some younger adults are diagnosed with lung cancers driven by biomarkers such as EGFR and ALK.
Researchers are working to understand whether these cancers develop through different biological pathways.
Why does this matter?
Understanding why some people develop lung cancer at a younger age could help improve:
Prevention
Early detection
Screening strategies
Research priorities
Future treatment approaches
Many questions remain unanswered, but researchers are gradually building a clearer picture of the factors that may contribute to early-onset lung cancer.
Related reading
Lung cancer in women: what ASCO 2026 tells us
Lung cancer in people who have never smoked