Major global study says prevention is our best hope for reducing cancer

Two older women smiling

New research in The Lancet quantifies cancer risk factors for countries around the world, across age, sex and over time

The 20 August front cover of The Lancet – a leading medical journal – had a powerful quote on it:

The primary prevention of cancer through eradication or mitigation of modifiable risk factors is our best hope of reducing the future burden of cancer.

The Lancet confirmed what World Cancer Research Fund have known for decades, that with more than 19 million new cases in 2020 worldwide, and 10 million deaths, “preventing cancer [is] the only way forward”.

Diana MackieThe front cover really struck me as it rang so true to everything we do here at World Cancer Research Fund. Having recently joined the charity as Head of Communications, I wanted to gain an in-depth understanding of this front cover and where our long legacy of robust research and advocacy fit in.

It was a huge encouragement to learn that our Recommendations provide the “best hope” for reducing the number of cancer cases in the future.

The Lancet‘s front cover refers to new research into how much cancer is attributable to certain risk factors, using data from the Global Burden of Disease (GBD) Study. This study involves more than 7,000 researchers in over 150 countries and territories, led by the Institute for Health Metrics and Evaluation, which is a global health research centre at the University of Washington in the US. The study is the most comprehensive worldwide ongoing epidemiological study to date.

What are attributable risk factors?

To prevent any disease, it’s important to understand which risk factors affect a population’s health. When it comes to cancer, we have long known that if you smoke, you increase your risk of developing lung and 14 other cancers. Today, in large part thanks to World Cancer Research Fund’s work, we now know that there are other modifiable risk factors that affect a person’s risk of developing cancer. These include an unhealthy diet, not having a healthy body weight, and not being physically active enough.

This particular research analysed results from the Global Burden of Disease, Injuries and Risk Factors Study 2019, the only study to date that quantifies risk factors for all countries, across age groups, for both sexes, and over time. The methodology in the GBD study used World Cancer Research Fund criteria for identifying risk factors, indicating the huge importance and robustness of our work.

Big risks from smoking, diet and pollution

The study found that modifiable risk factors including smoking, diet and air pollution accounted for 4.45 million deaths from cancer, of which 2.9 million were among men, and 1.6 million were among women. This represents 44.4% of all deaths from cancer.

Furthermore, cancer caused the loss of 105m healthy years of life (disability-adjusted life years or DALYs). This represents 42% of all healthy years lost due to cancer across the whole global population.

These percentages echo our research showing that around 40% of cancer cases are preventable through changes related to body weight, nutrition, physical activity and smoking, among others.

Behaviour contributes to cancer burden

The results of the study demonstrate that the leading risk factors contributing to the global cancer burden in 2019 were behavioural, including smoking, diet, obesity, alcohol and physical activity, but these vary by region and socio-demographic index. If we can reduce exposure to risk factors, we’ll be able to decrease the number of people developing – and dying from – cancer worldwide.

If 40% of cancers are preventable, this means that 60% are not. Therefore, efforts to prevent cancer must be coupled with improved early diagnosis, such as screening programmes and treatment. Prevention, diagnosis, treatment and survival go hand-in-hand.

On a global scale, a substantial proportion of the cancer burden could be prevented by reducing exposure to known cancer risk factors.

We’re influencing global policy

This research highlights the need for country-specific and regional cancer control and treatment policies to be developed by governments. The focus of these policies should be reducing people’s exposure to risk factors, and effectively screening for and treating the disease.

The high-profile GBD study demonstrates a clear need to link up the research findings with the people developing policies, and with the health departments focusing on diagnosis, treatment and survival. At World Cancer Research Fund we have a team of global policy experts, which means we’re well-placed to guide policymaking using the scientific evidence.

One thing is for sure: the burden of cancer is a huge public health challenge that is growing globally. Understanding how much of that burden is attributable to modifiable risk factors is crucial for the development of effective cancer prevention strategies.

I look forward to championing World Cancer Research Fund’s groundbreaking work and playing my part in reducing the cancer burden as I settle into my role here.

> Read the article in The Lancet

> We answer common questions about cancer