Why are more young people getting cancer? What is happening?

For a long time, we believed cancer was a disease linked almost exclusively to ageing. And age does remain one of the major risk factors. But the latest data from the Spanish Society of Medical Oncology (SEOM) for 2026 highlight an important point: the number of cases among young people and middle-aged adults is also growing.

Comparing the estimates for 2020 with those for 2026, we see that cases among people over 65 are rising by 8.24%. Among people under 65, the increase is 9.75%.

This is not the pattern we would expect. If ageing were the main driver of the increase, we would expect the rise among younger people to be clearly smaller than among older people. Although the difference is not enormous, the fact that it is higher is a warning sign: some diagnoses are appearing earlier than we used to expect.

What is happening? The causes of this early increase

There is no single answer. Cancer is a complex disease and we cannot reduce it to one habit or one cause. Even so, researchers point to several factors related to our current pace of life that could be bringing some diagnoses forward.

• Changes in diet and the microbiota. Unhealthy diets can alter our gut bacteria, and this affects processes such as inflammation and the immune response.
• The impact of antibiotics. Repeated, prolonged use since childhood could be playing a role in this trend, particularly through its relationship with the microbiota.
• Inactivity and obesity. We spend too much time sitting, and levels of overweight, even among children, continue to rise.
• Alcohol and tobacco. Alcohol consumption increases the risk of several types of cancer even at low levels. Tobacco remains one of the main preventable risk factors and is involved in the vast majority of lung cancers.

This does not mean blaming anyone. It means better understanding the context we live in so that we can prevent, detect earlier and provide better support.

Exercise: your ally against treatment toxicity

When we talk about cancer, physical exercise is not just about “doing sport”. In many cases, when properly prescribed and adapted, it can become a pillar that helps the body withstand the toxicity of treatments, such as chemotherapy, radiotherapy, immunotherapy or hormone therapy.

The evidence shows that staying active can reduce cancer-related fatigue, that extreme tiredness which does not always improve with rest, and improve perceived health during the process. It also helps maintain strength, muscle mass, mobility and independence.

In addition, people who exercise regularly can reduce the risk of mortality from the disease by almost 20%, according to the data collected by SEOM.

Ultimately, it is not just about surviving the diagnosis. It is about reaching the end of treatment with the best possible quality of life.

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