Lion Shahab, Jennifer A. McGowan, Jo Waller, Samuel G. Smith

Approximately one third to one half of cancer diagnoses are preventable by changes to lifestyle behaviours. In Europe, at least 1.1 million cancer cases per year could be prevented if people had healthier lifestyles. According to the latest (4th) European Code Against Cancer (ECAC), established cancer risk factors include active and passive smoking, alcohol consumption, being overweight or obese, being physically inactive, have a poor diet, being exposed to ultraviolet radiation (e.g. from the sun), and infection with human papillomavirus (HPV). However, many other unverified (‘mythical’) causes of cancer appear in tabloids and on social media. Recognising the difference between the real and the ‘mythical’ cancer causes can be difficult. Conflicting messages can make it harder for people who are trying to reduce their cancer risk to place their efforts into effective activities.

In a study published in the European Journal of Cancer, we report findings from the 2016 Attitudes and Beliefs About Cancer-UK Survey of 1,330 UK participants. The survey explored the public’s beliefs about actual cancer causes (smoking, alcohol consumption, low physical activity, low fruit and vegetable consumption, being overweight) and mythical causes of cancer. Awareness of actual causes of cancer was low, with participants on average on being able to identify half of the causes of cancer. More than a third (40%) of adults did not know that being overweight was associated with an increased cancer risk and the same number did not recognise sunburn as a cancer risk. Almost three in four adults (71%) did not know that HPV is associated with cancer. Being able to identify correct causes of cancer was related to the likelihood of participants not smoking, and eating five or more fruit and vegetables a day.

Participants could, on average, only identify 36% of mythical causes of cancer as incorrect. Of these, adults were most likely to believe that stress (43%), food additives (42%) and electromagnetic frequencies (35%) caused cancer. A quarter (26%) of participants believed that mobile phones could cause cancer. Interestingly, adults who endorsed the actual causes of cancer were also more likely to also believe in the mythical causes, suggesting a great level of confusion between the two.

If people are to make informed decisions about their lifestyle they need an accurate understanding of cancer risk factors. Our survey shows that there is a large degree of confusion among the general public regarding those risks. It seems that the numbers of people who believe in the unfounded causes of cancer has increased over the last decade. This could be linked to the way people now access information and the rise of so-called “fake news”. Looking for information from reputable websites like NHS Choices and Cancer Research UK is a good way to avoid this. Cancer Research UK even has a page presenting evidence to debunk some the myths, which could be a useful resource for people who are understandably confused.

by Anna Roberts

Over 14 million people are diagnosed with cancer worldwide each year, and this is expected to rise to 22 million over the next two decades. Thankfully, due to improvements in early diagnosis and treatment, the number of people who are surviving longer after cancer is also increasing.

However, many people diagnosed with cancer experience long-lasting and debilitating side effects (e.g. fatigue, pain, sleep difficulties, anxiety and depression), all of which can substantially reduce quality of life. Health behaviours, such as physical activity and diet could prolong survival, reduce the risk of cancer returning and have been shown to reduce many of these common side effects. However, it is many of these side effects which make physical activity more difficult to do following a cancer diagnosis, and the number of cancer survivors who meet the recommended 150 minutes of moderate-vigorous physical activity per week is lower than for people who have never had cancer.  Therefore, there is a need for interventions which can help support cancer survivors’ to take part in physical activity following their diagnosis.

Digital interventions use technologies such as text messaging, email, mobile apps, social media, websites and patient portals can be used to support health behaviours such as physical activity and diet. Digital interventions have increased in popularity as they are easy to access, tend to cost less than face-to-face support and therefore have the ability to reach a large number of people. This is especially true given the ever increasing number of UK adults who access the internet and own a smartphone.

In the last few years, the number of studies which have looked at how effective these types of technologies are at improving cancer survivors’ physical activity participation and diet quality has rapidly increased. In our new study, we reviewed all of the published literature to see how effective digital technologies are at increasing physical activity or improving dietary quality among people diagnosed with cancer. We also looked at the effect of these types of interventions on body mass index (BMI) and other cancer-relevant outcomes measured in the studies, such as fatigue, sleep quality, anxiety and depression and quality of life.

15 studies were included in the review, all of which evaluated the effect of a digital technology on physical activity and five studies also evaluated the effect on dietary quality. By statistically combining the data from the studies (also known as a meta-analysis), we were able to estimate that digital technologies can increase cancer survivors’ moderate-vigorous physical activity by approximately 40 minutes per week. This technique also allowed us to show that digital technologies can significantly reduce BMI, however there was no evidence of an improvement in cancer survivors’ quality of life. While there was evidence for a reduction in fatigue, this was not large enough to be deemed statistically significant. Meta-analysis was not possible for all of the outcomes we were interested in (either due to the variation between studies in the way in which they were measured or because of the small number of studies which assessed these outcomes). Of the 5 studies which assessed the effect of digital interventions on diet, only 2 showed an improvement in dietary quality. There was no evidence of any improvement in anxiety or depression and while only 2 studies evaluated the effect on sleep quality, both showed a significant improvement in sleep outcomes.

However, as this is an emerging field of research, the quality of the included studies was varied. For instance, all of the studies asked participants to report their own physical activity participation using questionnaires. These types of questionnaires are notorious for overestimating actual physical activity levels. Furthermore, the length of follow-up in these studies was relatively short which makes it difficult to understand the longer-term impact of these types of interventions. There was also large variation between the studies in terms of the types of digital interventions, the types of cancer and the way in which the outcomes were measured. This makes it very difficult to ascertain what types of intervention are most effective, for which outcomes, among which groups of cancer survivors. While the results of this review show that the use of digital technologies in this context appears promising, we also call for larger, high-quality studies with objective measures of physical activity and longer follow-up periods.

Article link: Roberts AL, Fisher A, Smith L, Heinrich M, Potts HWW. Digital health behaviour change interventions targeting physical activity and diet in cancer survivors: a systematic review and meta-analysis. Journal of Cancer Survivorship, 2017.