Lifestyle factors in cancer survivors-We have the evidence, but are we doing enough?

Abstract

The benefits to cancer survivors of a healthy diet, keeping to a healthy weight and physical activity are well-recognised—as the worldwide population of cancer survivors grows, so do the number of strategies targeting lifestyle-related behaviours. Physical activity interventions are generally safe for cancer survivors and have few adverse effects—their benefits include improvements in fitness, physical function and cancer-related psychosocial variables (Morey et al., 2009). Further, diet and exercise may positively influence biomarkers associated with progressive disease and overall survival. There is a substantial effect amongst cancer survivors of physical activity interventions’ post-treatment on body strength, with some (more modest) effects on fatigue (Speck, Courneya, Mâsse, Duval, & Schmitz, 2010)—and exercise is generally well-tolerated amongst cancer survivors. A number of barriers have been reported in the literature; typical patient-related barriers include being “too busy” and a “lack of willpower”—although barriers can vary between cancer types and patient groups (Ottenbacher et al., 2011). More recently the emphasis in overcoming these barriers has been on developing high-reach, sustainable interventions which can reach very broad and diverse populations—this is particularly needed if studies are to include sufficient subgroups to ensure generalisability of findings. A recent meta-analysis of randomised controlled trials found that physical activity was associated with improvements in muscle strength (bench press and leg press), fatigue, depression and quality of life—as well as important biomarkers such as insulin-like growth factor-I (Fong et al., 2012). Furthermore, when studies on different types of cancer were combined, there were improvements in body mass index (BMI), body weight, peak oxygen consumption, peak power output and speed. Of course, studies vary in terms of their target group, quality, study size and nature of the physical activity intervention, but the overall message is clear and consistent—physical activity has a broad range of benefits and, if undertaken appropriately, can improve the quality of life of cancer survivors. So how do healthcare professionals (HCPs) respond to the challenge of improving “lifestyle” factors, such as physical activity, diet and obesity in their patients with cancer? Interestingly, it appears there are few barriers to raising the topics of diet, smoking and alcohol—yet body weight and exercise are mentioned much less frequently (Miles, Simon, & Wardle, 2010). Reluctance to discuss these important lifestyle factors appears to arise from a desire to minimise patient distress—but limitations in health providers’ knowledge and their perceptions of the quality and strength of evidence about lifestyle factors also appear to be important. These important areas of research and practice are tackled by several authors in this issue of the Journal. Morishita et al. (2018) examine muscle strength in long-term cancer survivors—and confirm it is an important factor in improving quality of life, reinforcing the need to focus not just on cardiovascular fitness in cancer rehabilitation programmes. Travier et al. (2018), in their pre- and postintervention study, add further to the evidence that diet and exercise interventions can impact favourably on metabolic risk biomarkers in patients with cancer—in this case also improving indicators of insulin resistance. Haussmann et al. (2018) undertook a qualitative study examining factors which might hinder HCPs in recommending physical activity in their patients with cancer. HCPs were concerned with the physical overexertion and psychological stress which might arise from a recommendation for physical activity. Other factors included the physical and social environments of the patient with cancer and the availability of exercise programmes. It is important for HCPs to consider physical activity recommendations, taking into account patient circumstances—and to not be “put off” by factors which there may have little relevance to their patient's circumstances. del Valle, Martín-Payo, Cuesta-Briand, and Lana (2018) examined dietary behaviours in women with breast cancer—they found that a relatively simple intervention (a booklet with or without telephone follow-up) was effective in bringing about sustainable improvements in diet (such as greater consumption of fruit and vegetables and lower fat intake). These findings add to the growing body of evidence that simple, cost-effective lifestyle interventions can bring about dietary changes in patients with cancer—changes which are sustainable well beyond the life of the intervention. Lifestyle interventions in patients with cancer are important, but sometimes neglected. They are often inexpensive and can produce sustainable effects. HCPs and those involved in planning cancer services should ensure that lifestyle is a central consideration in the care for our growing numbers of cancer survivors.