Lifestyle Medicine in Cancer Care

Stevens, Forster and Manger present a state-of-the-art narrative review examining the role of lifestyle medicine across the cancer continuum, from primary prevention through active treatment and survivorship. They selected articles published in English between 2010 and 2025, together with earlier seminal studies. The included literature comprised systematic reviews, meta-analyses, randomised controlled trials, and other influential studies in the field. The review published in September 2026 is organised around six pillars of lifestyle medicine: nutrition, physical activity, sleep, stress management, social connections, and avoidance of risky substances. The authors propose that these domains provide a clinically useful framework because a substantial proportion of the cancer burden is associated with modifiable factors, while lifestyle interventions may improve treatment tolerance, quality of life, and survivorship outcomes. Although not all of the information presented is new, the review provides a useful synthesis and reminder of the available evidence supporting the potential role of holistic lifestyle interventions in cancer prevention and management. 1. Nutrition: Mediterranean and plant-based diets, food quality, fibre, and the microbiome Evidence is strongest for plant-predominant and Mediterranean-style dietary patterns. These diets emphasise vegetables, fruits, whole grains, legumes, nuts, olive oil, and fish, and are associated with a lower incidence of several cancers, particularly breast and colorectal cancer. Proposed mechanisms include reductions in inflammation and oxidative stress, improved insulin signalling, reduced DNA damage, and modulation of cellular proliferation and angiogenesis. Additional mechanisms include the anti-inflammatory effects of oleocanthal and monounsaturated fats in olive oil, as well as the influence of fish-derived omega-3 fatty acids and the omega-3 to omega-6 balance on inflammatory pathways and tumour growth. However, much of the evidence remains observational, and direct confirmation from cancer-specific randomised trials is limited. Across several studies, greater adherence to Mediterranean dietary recommendations was associated with substantial reductions in breast cancer risk, of approximately 25%–60%, and colorectal cancer risk, of around 48%. In contrast, red and processed meat intake was associated with increased colorectal cancer risk, with a relative risk of 1.08 per 30 g/day. Replacing some red meat with whole grains, fruits, and vegetables was associated with a lower risk. Ultra-processed foods were also associated with several cancers, while consuming 50 g/day of processed meat was associated with an approximately 18% increase in colorectal cancer risk. Even within plant-predominant diets, food quality appears important. A prospective cohort study of breast cancer survivors found lower mortality among patients consuming a healthy plant-based diet, rich in whole grains, fruits, vegetables, nuts, and legumes, compared with those consuming an unhealthy plant-based diet characterised by refined grains, fruit juices, and sugar-sweetened beverages. Higher fibre intake may also support a beneficial gut microbiome, reinforcing the importance of judicious antibiotic use because antibiotics may alter microbiome composition. 2. Physical activity: intensity and timing, resistance training, and muscle mass Physical activity has one of the strongest evidence bases among the six pillars. Regular exercise is associated with a reduced incidence of multiple cancer types through mechanisms including a decrease in the activity of pathways involving insulin and insulin-like growth factor (IGF-1), improved immune function, reduced systemic inflammation, regulation of sex hormones, and prevention of excess adiposity. Some evidence suggests that these protective associations persist even after adjustment for Body Mass Index (BMI), indicating an effect of physical activity that is at least partly independent of body weight. Exercise is also clinically important after diagnosis. In a randomised trial in colon cancer involving 889 patients across 55 centres, a structured exercise programme was associated with a 28% lower risk of recurrence, new primary cancer, or death over a median follow-up of 7.9 years. Benefits are not limited to high levels of physical activity; moderate physical activity has also been associated with a lower risk of death among breast cancer survivors. Across cancer populations, exercise interventions improve cardiorespiratory fitness, strength, fatigue, anxiety, depression, and quality of life. The review also highlights the importance of timing physical activity across the cancer journey. Increased activity after diagnosis may be associated with lower mortality risk, and exercise prescriptions are increasingly being adapted to chemotherapy schedules in order to account for fluctuations in symptoms and treatment burden. Resistance training may be particularly valuable for preventing or managing sarcopenia and cachexia and for improving treatment tolerance. The review emphasises that skeletal muscle depletion is an important prognostic factor independent of BMI. Consequently, exercise and nutritional strategies should prioritise the preservation of lean muscle rather than focusing exclusively on body weight reduction. 3. Sleep: duration, quality, and circadian rhythm The evidence linking sleep with cancer outcomes is less consistent than that for diet or exercise. Studies examining sleep duration have produced heterogeneous results, with no clear overall association between short or long sleep duration and total cancer risk. Poor sleep quality may be more clinically relevant, with observational studies suggesting associations between impaired sleep and increased cancer risk. Circadian rhythm disruption may also contribute to carcinogenesis through hormonal disturbances, impaired DNA repair, immune dysregulation, and metabolic changes. Shift work involving circadian disruption has been classified by the International Agency for Research on Cancer as “probably carcinogenic”. The authors suggest maintaining regular sleep-wake patterns and minimising nocturnal light exposure, while acknowledging that evidence for specific sleep interventions improving cancer outcomes remains limited. They also discuss the potential value of aligning cancer treatment schedules with circadian rhythms to improve treatment efficacy and reduce toxicity. 4. Depression and stress management Psychological distress, depression, and chronic stress are common throughout the cancer trajectory and have been associated with poorer outcomes. Depression after cancer diagnosis has been observationally associated with an increase in cancer-specific mortality. However, causality cannot be assumed, as disease severity and treatment burden may themselves contribute to psychological distress. Cognitive behavioural therapy and mindfulness-based interventions have the clearest evidence for symptom management. Meta-analyses demonstrate reductions in anxiety, depression, and cancer-related fatigue, alongside improvements in health-related quality of life. Potential mechanisms include modulation of neuroendocrine pathways, systemic inflammation, and immune function. Evidence that psychological interventions directly improve cancer survival, however, is substantially less certain. 5. Social connections: social isolation, loneliness, and relationship quality Social isolation and loneliness are increasingly recognised as clinically relevant determinants of cancer outcomes. Large observational analyses associate loneliness with a 34% increase in all-cause mortality and an 11% increase in cancer-specific mortality. Social isolation has also been associated with poorer outcomes among cancer survivors. However, reverse causation remains an important limitation, as advancing disease, fatigue, pain, and treatment effects may themselves contribute to social withdrawal. The quality of social relationships may be more important than the number of social contacts. Emotional and practical support appear relevant to both psychological and physical wellbeing. The authors therefore recommend that clinicians consider screening for both objective social isolation and subjective loneliness and, where appropriate, facilitate access to peer-support groups, community programmes, and family-based interventions. 6. Avoidance of risky substances Tobacco cessation represents one of the most important interventions across the cancer continuum. Smoking cessation reduces future cancer risk and is associated with improved outcomes following diagnosis. For example, for cancers of the larynx, oral cavity, and pharynx, the review reports an approximately 50% reduction in risk between 5 and 9 years after cessation. Patients who stop smoking after diagnosis may also experience improved overall survival, fewer treatment-related complications, and better therapeutic responses compared with those who continue smoking. Alcohol is also an established carcinogenic exposure. Consumption is associated with cancers of the oral cavity and pharynx, with a relative risk of 5.7 at the highest consumption levels, as well as oesophageal cancer (relative risk 4.2), laryngeal cancer (3.2), and cancers of the liver, colorectum, and breast. Risk generally increases as intake rises. The review highlights evidence of increased cancer risk even at relatively low levels of alcohol consumption and notes that no clearly safe level has been established for cancer prevention. Clinical implications Taken together, the six-pillar framework supports the integration of lifestyle assessment and counselling into routine oncology care alongside  standard anticancer treatment. The strongest evidence currently supports physical activity, smoking cessation, mediterranean and plant-predominant dietary patterns, and optimisation of body composition. Evidence relating to sleep, stress-management interventions, social connection, and microbiome-directed strategies is promising but less consistent or relies more heavily on observational studies. The authors also highlight that the implementation of lifestyle medicine in cancer care remains limited, with fewer than “25% of cancer survivors meeting basic lifestyle goals”. Limitations The authors emphasise several important methodological limitations. This is a narrative rather than a systematic review, much of the evidence is observational, study populations and interventions are heterogeneous, and Western cohorts are over-represented. Selection bias, residual confounding, and reverse causation therefore limit causal interpretation. Greater use of pragmatic trials, more diverse study populations, and further implementation research will be needed before many lifestyle interventions can be incorporated consistently into cancer prevention and treatment pathways.