Study Protocol to Investigate the Effect of a Lifestyle Intervention on Body
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BMC Cancer BioMed Central Study protocol Open Access Study protocol to investigate the effect of a lifestyle intervention on body weight, psychological health status and risk factors associated with disease recurrence in women recovering from breast cancer treatment [ISRCTN08045231] John M Saxton*1, Amanda Daley2, Nicola Woodroofe3, Robert Coleman4, Hilary Powers5, Nanette Mutrie6, Vanessa Siddall4 and Helen Crank1 Address: 1Centre for Sport and Exercise Science, Sheffield Hallam University, Sheffield, UK, 2Department of Primary Care and General Practice, University of Birmingham, UK, 3Biomedical Research Centre, Sheffield Hallam University, Sheffield, UK, 4Academic Unit of Clinical Oncology, University of Sheffield, Weston Park Hospital, Sheffield, UK, 5Centre for Human Nutrition, University of Sheffield, UK and 6Department of Sport, Culture and the Arts, Strathclyde University (Jordanhill Campus), Glasgow, UK Email: John M Saxton* - [email protected]; Amanda Daley - [email protected]; Nicola Woodroofe - [email protected]; Robert Coleman - [email protected]; Hilary Powers - [email protected]; Nanette Mutrie - [email protected]; Vanessa Siddall - [email protected]; Helen Crank - [email protected] * Corresponding author Published: 09 February 2006 Received: 31 October 2005 Accepted: 09 February 2006 BMC Cancer 2006, 6:35 doi:10.1186/1471-2407-6-35 This article is available from: http://www.biomedcentral.com/1471-2407/6/35 © 2006 Saxton et al; licensee BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Abstract Background: Breast cancer survivors often encounter physiological and psychological problems related to their diagnosis and treatment that can influence long-term prognosis. The aim of this research is to investigate the effects of a lifestyle intervention on body weight and psychological well-being in women recovering from breast cancer treatment, and to determine the relationship between changes in these variables and biomarkers associated with disease recurrence and survival. Methods/design: Following ethical approval, a total of 100 patients will be randomly assigned to a lifestyle intervention (incorporating dietary energy restriction in conjunction with aerobic exercise training) or normal care control group. Patients randomised to the dietary and exercise intervention will be given individualised healthy eating dietary advice and written information and attend moderate intensity aerobic exercise sessions on three to five days per week for a period of 24 weeks. The aim of this strategy is to induce a steady weight loss of up to 0.5 Kg each week. In addition, the overall quality of the diet will be examined with a view to (i) reducing the dietary intake of fat to ~25% of the total calories, (ii) eating at least 5 portions of fruit and vegetables a day, (iii) increasing the intake of fibre and reducing refined carbohydrates, and (iv) taking moderate amounts of alcohol. Outcome measures will include body weight and body composition, psychological health status (stress and depression), cardiorespiratory fitness and quality of life. In addition, biomarkers associated with disease recurrence, including stress hormones, estrogen status, inflammatory markers and indices of innate and adaptive immune function will be monitored. Discussion: This research will provide valuable information on the effectiveness of a practical, easily implemented lifestyle intervention for evoking positive effects on body weight and psychological well-being, two important factors that can influence long-term prognosis in breast cancer survivors. However, the added value of the study is that it will also evaluate the effects of the lifestyle intervention on a range of biomarkers associated with disease recurrence and survival. Considered together, the results should improve our understanding of the potential role that lifestyle-modifiable factors could play in saving or prolonging lives. Page 1 of 9 (page number not for citation purposes) BMC Cancer 2006, 6:35 http://www.biomedcentral.com/1471-2407/6/35 Background tion, studies have reported abnormal circadian rhythmic- Although the number of women who survive breast can- ity of cortisol in breast cancer patients [35-39] and cer is increasing, survivors often encounter physiological flattened or abnormal diurnal salivary cortisol rhythms and psychological problems related to their diagnosis and have recently been associated with earlier mortality in treatment that can influence long-term prognosis. A gain breast cancer patients [38] and persistent fatigue in survi- in body weight [1-6] and psychosocial distress [7-12] are vors 1–5 years after initial diagnosis [40]. two commonly encountered adverse responses to breast cancer diagnosis and treatment that can have a negative Dietary energy restriction can reduce body weight and impact on quality of life and survival. Lifestyle strategies induce a positive effect on psychological well being in that can attenuate the negative effects of such physical and obese women and breast cancer survivors [41-44]. Weight mental health outcomes after breast cancer diagnosis loss interventions that reduce dietary intake of fat to 18– could further improve the quality of life and long-term 25% of the total calories can also evoke a significant prognosis of breast cancer survivors. reduction in serum estrogen levels in pre and postmeno- pausal women [45]. The positive effects of dietary energy Up to 60% of women diagnosed with breast cancer expe- restriction on these physical and emotional sequelae rience an increase in body weight associated with chemo- might be augmented by the implementation of adjunctive therapy and treatment-related menopause [6] and there is exercise therapy [46,47]. Regular physical activity can help evidence that heavier women and women who gain to control body weight and is known to reduce the risk of weight after diagnosis have an increased risk of disease breast cancer [48-53]. Recent evidence also suggests that it recurrence and death compared to normal weight women can halve the risk of death in breast cancer patients [54]. [1-5]. Women with a high body mass index (BMI) have The precise mechanisms underpinning the positive effects double the risk of 5-year recurrence and a 60% increased of physical activity on breast cancer risk and survival are risk of death over 10 years in comparison to normal- unknown, although physical activity has been associated weight women [5]. Poorer survival in heavier patients with a lower concentration of circulating estrogen in some could be due to higher levels of tumor-promoting hor- studies [55,56], as well as lower circulating levels of the mones, consequent to an increased adiposity [13]. There inflammatory mediators, C-reactive protein (CRP) [57- is evidence that elevated estrogen levels influence the risk 59] and interleukin-6 (IL-6) [60,61]. Increased CRP levels of breast cancer in postmenopausal women [14-16] and it are observed in overweight individuals [62,63] and have was recently shown that overweight postmenopausal been linked with increased cancer risk [64,65] and ele- breast cancer patients have higher estrogen and testoster- vated levels of cortisol in individuals subjected to psycho- one levels than normal-weight patients [13]. This led to logical stress [66]. Depression enhances the production of the suggestion that circulating estrogen levels could be a IL-6 [67-69] and this proinflammatory cytokine is also useful biomarker for weight loss intervention studies [13]. secreted from adipocytes in proportion to body fat mass [60]. IL-6 induces CRP synthesis in the liver and can indi- Following breast cancer diagnosis or treatment, four in ten rectly raise cortisol levels via stimulation of corticotropin- women also experience high levels of emotional distress, releasing hormone production [67]. Elevated estrogen including depression and anxiety [7], which persists for levels may also increase CRP levels through a non-inflam- prolonged periods of time, irrespective of the treatment matory mechanism [70]. outcome [8-12]. Studies have shown that psychosocial stressors such as depression, anxiety and emotional dis- Regular physical activity can also have a positive effect on tress are associated with impaired immune function [17], psychological health status [71,72] and quality of life [73] and this could have a direct impact on cancer outcomes in breast cancer survivors that could enhance immune [18,19] and influence the risk of disease re-occurrence and function through normalisation of stress hormone levels. death [20]. The adverse effect of psychosocial stressors on Although there is evidence for decreased cortisol levels immune function is considered to be mediated by excess [74,75] and changes in immune cell numbers and func- secretion of the stress hormone cortisol and the catecho- tion after psychosocial interventions in breast cancer lamines [21,22]. Elevated cortisol and catecholamine lev- patients [76,77], only three studies have investigated the els evoked by psychological stressors can significantly effects of exercise therapy on immune function in breast influence immune function, including lymphocyte prolif- cancer survivors. Peters et al. [78,79] reported an increase eration and natural