Obesity in breast cancer--what is the risk factor?
Environmental factors influence breast cancer incidence and progression. High body mass index (BMI) is associated with increased risk of post-menopausal breast cancer and with poorer outcome in those with a history of breast cancer. High BMI is generally interpreted as excess adiposity (overweight or obesity) and the World Cancer Research Fund judged that the associations between BMI and incidence of breast cancer were due to body fatness. Although BMI is the most common measure used to characterise body composition, it cannot distinguish lean mass from fat mass, or characterise body fat distribution, and so individuals with the same BMI can have different body composition. In particular, the relation between BMI and lean or fat mass may differ between people with or without disease. The question therefore arises as to what aspect or aspects of body composition are causally linked to the poorer outcome of breast cancer patients with high BMI. This question is not addressed in the literature. Most studies have used BMI, without discussion of its shortcomings as a marker of body composition, leading to potentially important misinterpretation. In this article we review the different measurements used to characterise body composition in the literature, and how they relate to breast cancer risk and prognosis. Further research is required to better characterise the relation of body composition to breast cancer.
Cancer Sciences Division, University of Southampton, UK; Jesus College, The University of Cambridge, UK.
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James
Southampton NIHR Biomedical Research Centre, University Hospitals Southampton, UK.
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Wootton
Southampton NIHR Biomedical Research Centre, University Hospitals Southampton, UK.
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Jackson
Southampton NIHR Biomedical Research Centre, University Hospitals Southampton, UK.
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Wiseman
Cancer Sciences Division, University of Southampton, UK.
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Copson
Southampton Breast Surgical Unit, University Hospitals Southampton, UK; Cancer Sciences Division, University of Southampton, UK. Electronic address: r.i.cutress@soton.ac.uk.
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Cutress
D050154:Adiposity; D015992:Body Mass Index; D001943:Breast Neoplasms / Q000150:complications*; D005260:Female; D006801:Humans; D009765:Obesity / Q000150:complications*; D011379:Prognosis; D012307:Risk Factors
Body composition; Body fatness; Breast cancer; Fat free mass; Fat mass; Intervention; Prognosis; Risk factor