Post-diagnosis adiposity, physical activity, sedentary behaviour, dietary factors, supplement use and colorectal cancer prognosis: Global Cancer Update Programme (CUP Global) summary of evidence grading.

Based on the World Cancer Research Fund Global Cancer Update Programme, we performed systematic reviews and meta-analyses to investigate the association of post-diagnosis adiposity, physical activity, sedentary behaviour, and dietary factors with colorectal cancer prognosis. We searched PubMed and Embase until 28th February, 2022. An independent expert committee and expert panel graded the quality of evidence. A total of 167 unique publications were reviewed, and all but five were observational studies. The quality of the evidence was graded conservatively due to the high risk of several biases. There was evidence of non-linearity in the associations between body mass index and colorectal cancer prognosis. The associations appeared reverse J-shaped, and the quality of this evidence was graded as limited (likelihood of causality: limited-no conclusion). The evidence on recreational physical activity and lower risk of all-cause mortality (relative risk [RR] highest vs. lowest: 0.69, 95% confidence interval [CI]: 0.62-0.77) and recurrence/disease-free survival (RR: 0.80, 95% CI: 0.70-0.92) was graded as limited-suggestive. There was limited-suggestive evidence for the associations between healthy dietary and/or lifestyle patterns (including diets that comprised plant-based foods), intake of whole grains and coffee with lower risk of all-cause mortality, and between unhealthy dietary patterns and intake of sugary drinks with higher risk of all-cause mortality. The evidence for other exposures on colorectal cancer outcomes was sparse and graded as limited-no conclusion. Analyses were conducted excluding cancer patients with metastases without substantial changes in the findings. Well-designed intervention and cohort studies are needed to support the development of lifestyle recommendations for colorectal cancer patients.

Nutrition and cancer: prevention and survival.

Cancer is increasing worldwide. Patterns of cancer are also changing. The evidence is summarised in the 2018 World Cancer Research Fund/American Institute for Cancer Research report Diet, Nutrition, Physical Activity and Cancer: a Global Perspective. The plasticity of cancer patterns implicates environmental factors as determinants of cancer, and nutrition influences key cellular and molecular processes that characterise cancer. Epidemiology identifies associations between aspects of diet, nutrition, and physical activity with one or more cancers; there is evidence for plausible mechanisms that imply that these are causal. Some nutritional exposures (alcohol and processed meat) are likely causal factors, but no singular factor protects against cancer (except dietary fibre for colorectal cancer). Cancer protection mainly derives from a systemic metabolic environment that promotes healthy cell replication and tissue integrity. Such a nutritional state reflects avoiding excess adiposity through healthy dietary patterns rich in plant foods (legumes, wholegrains, pulses, vegetables and fruits), with modest meat, fish and dairy, low in alcohol and salt preserved foods, and an active way of life, avoiding sedentary behaviours. Less is known about the impact of nutritional interventions in people with a diagnosis of cancer, but nutrition including adiposity and physical activity predict breast cancer outcome. Promoting healthy ways of life requires public information and education, but alone these do not generate change; a socio-political and cultural environment that is conducive to adopting healthy behaviours is needed. Uncertainties in the evidence offer promising directions for future research, but sufficient is known to act as a basis for public policy and clinical practice.

The use and interpretation of anthropometric measures in cancer epidemiology: A perspective from the world cancer research fund international continuous update project.

Anthropometric measures relating to body size, weight and composition are increasingly being associated with cancer risk and progression. Whilst practical in epidemiologic research, where population-level associations with disease are revealed, it is important to be aware that such measures are imperfect markers of the internal physiological processes that are the actual correlates of cancer development. Body mass index (BMI), the most commonly used marker for adiposity, may mask differences between lean and adipose tissue, or fat distribution, which varies across individuals, ethnicities, and stage in the lifespan. Other measures, such as weight gain in adulthood, waist circumference and waist-to-hip ratio, contribute information on adipose tissue distribution and insulin sensitivity. Single anthropometric measures do not capture maturational events, including the presence of critical windows of susceptibility (i.e., age of menarche and menopause), which presents a challenge in epidemiologic work. Integration of experimental research on underlying dynamic genetic, hormonal, and other non-nutritional mechanisms is necessary for a confident conclusion of the overall evidence in cancer development and progression. This article discusses the challenges confronted in evaluating and interpreting the current evidence linking anthropometric factors and cancer risk as a basis for issuing recommendations for cancer prevention.

Nutrition and cancer - global and African perspectives: a focused update.

The burden of cancer worldwide is predicted to almost double by 2030 to nearly 23 million cases annually. The great majority of this increase is expected to occur in less economically developed countries, where access to expensive medical, surgical and radiotherapeutic interventions is likely to be limited to a small proportion of the population. This emphasises the need for preventive measures, as outlined in the declaration from the United Nations 2011 High Level Meeting on Non-communicable Diseases. The rise in incidence is proposed to follow from increasing numbers of people reaching middle and older ages, together with increasing urbanisation of the population with a nutritional transition from traditional diets to a more globalised 'Western' pattern, with a decrease in physical activity. This is also expected to effect a change in the pattern of cancers from a predominantly smoking and infection dominated one, to a smoking and obesity dominated one. The World Cancer Research Fund estimates that about a quarter to a third of the commonest cancers are attributable to excess body weight, physical inactivity and poor diet, making this the most common cause of cancers after smoking. These cancers are potentially preventable, but knowledge of the causes of cancer has not led to effective policies to prevent the export of a 'Western' pattern of cancers in lower income countries such as many in Africa.

Defining the state of knowledge with respect to food, nutrition, physical activity, and the prevention of cancer.

The 1997 World Cancer Research Fund and the American Institute for Cancer Research (WCRF/AICR) report, Food, Nutrition and the Prevention of Cancer: a global perspective, has become the most authoritative statement on the topic. WCRF International has begun the process of producing its second global report on food, nutrition, physical activity, and the prevention of cancer. The process is in three stages. The first begins with the development of a suitable methodology as advised by a task force of experts. The second stage will involve the systematic collection and display of the evidence by independent review teams. The final stage will be the assessment and judgment of that evidence by an independent panel of experts responsible for the content of the report, including its conclusions and recommendations. Two major differences between this report and previous reports on the prevention of chronic diseases are that a portfolio approach to the evidence is being used in which all types of study are weighed and the process of collecting and displaying the evidence is being clearly separated from assessment and judgment. This paper outlines the methodological procedures and their development that will be applied for the second WCRF International report.