Updated cancer prevention guideline: physical activity is key

Admin • 2020.09.11

As a result of novel scientific evidence, the American Cancer Society has updated its guideline on lifestyle recommendations for the first time in 8 years, further emphasizing the possibilities of prevention. Could increased physical activity and diet change be our secret weapon against cancer? We looked into the details in our new post. 

Despite the robust efforts in anti-cancer drug development and increasing evidence that many malignancies are preventable, cancer currently outranks cardiovascular disease as the number one cause of death in the US under the age of 80. It has been shown that both screening activities (secondary prevention) and preventive measures focusing on environmental and lifestyle risk factors (primary prevention) can reduce cancer mortality. 

Our knowledge is expanding significantly but this expansion does not appear in the statistics. It is estimated that 50% of cancer cases are preventable thus these cases can be seen as missed opportunities. Despite the scientific advances, population-level implementation of cancer prevention strategies did not show convincing results so far.

As a consequence, at the beginning of June 2020, the American Cancer Society (ACS) has updated its guideline on diet and physical activity for cancer prevention for the first time since 2012. Their recommendation for individuals consists of four main points:

•       Achieve and maintain a healthy body weight throughout life.
•       Be physically active.
•       Follow a healthy eating pattern at all ages.
•       It is best not to drink alcohol.

To give a better idea of what has changed in eight years, we have summarized the most important changes in the new guideline comparing it with the last one in the next table:

Why physical activity?

The changes in the recommendations are based on scientific evidence published since 2012. The evidence that supports that regular physical activity is one of the most important lifestyle factor prevention strategies can focus on is increasing. To illustrate this concept, we can look into a 25-years long cohort study that was published in May 2020.

In this study, data from the Office for National Statistics of England and Wales were analyzed in order to assess how different ways of commuting (using a car, public transport, walking, or cycling to work and from work) compares in terms of all-cause mortality, cancer mortality and cancer incidence. A population of approximately 395 000 individuals was divided into groups based on different variables and then the relative risk of these groups was compared for certain studied events.

Their results show that compared to using a private motorized vehicle, bicycle commuting was associated with a reduced rate of all-cause mortality, cancer mortality, and cancer incidence; walk-commuting was associated with lower cancer incidence, and using public transport (more specifically railways) to commute resulted in a decrease of all-cause mortality and cancer incidence.

But what causes these differences?

Different commuting ways result in differences in average physical activity, the amount of inhaled air pollutants, noise, or even stress. The exact health effects of these exposures however are not completely understood.

Bicycle commuting results in a marked increase of weekly physical activity but also an increase in the amount of inhaled pollutants due to increased respiration rate and respiratory volume. Considering that bicycle commuting was associated with the lowest cancer incidence and mortality out of all four assessed forms, this finding could suggest that the benefit of regular physical activity outweighs other possible disadvantages such as inhaled pollutants. The same study highlights that using a private motorised vehicle is by far the most common method of commuting chosen by 67%, while cycling is the least common out of the assessed four preferred by only 3% of the studied population.

As the diagnosis of cancer is a heavy burden both for the affected patient and their relatives and friends, preventive measures should be the foremost choice of weapon in the fight against cancer. Prevention is not only effective but it is the only tool that decreases the number of cancer diagnoses as well as cancer mortality.

Individual and community actions together are needed to raise awareness of known risk factors and to provide accessible and affordable ways to implement adequate lifestyle changes for individuals. Making healthy lifestyle changes is not an easy task but – according to science – a very much rewarding investment.