Body composition changes in females treated for breast cancer: a review of the evidence

Association between changes in body fat and disease progression after breast cancer surgery is moderated by menopausal status

Background

Obesity is linked to poor disease outcomes in breast cancer patients. However, this link was mostly based on body weight or BMI rather than body-fat. The purpose of this study was to evaluate the relationship between body-fat gain and disease progression in Taiwanese women after breast cancer surgery and how this relationship is influenced by menopausal status.

Methods

Body fat percentage was measured 1 day before and 6 months after surgery in 131 women with stages 0–III breast cancer. Disease outcomes (metastasis and death) were assessed by chart review and telephone contact 7 to 8 years after diagnosis. These data were analyzed by multivariate Cox proportional hazard model analysis.

Results

The percentage of women with over 5% gain in body-fat was 56% for premenopausal and 42% for postmenopausal. Rates of distant metastasis and all-cause mortality were 17.6 and 9.9%, respectively over the follow-up period. Distant metastases were predicted in postmenopausal but not premenopausal women with breast cancer by increased body fat percentage (HR = 1.3, p = 0.035), after controlling other potential covariates, including disease severity, estrogen receptor expression, progesterone receptors expression, age, and exercise habit before diagnosis. Survival was not significantly associated with body-fat percentage gains.

Conclusions

Our results suggest that increased body fat percentage 6 months after breast surgery is an important predictor of distant metastasis in postmenopausal Taiwanese women with breast cancer. Clinicians may need to measure patients’ body fat periodically. Our findings should be validated in studies with a longer follow-up time.

Exploration of Exercise Outcome Expectations Among Breast Cancer Survivors

BACKGROUND

Exercise is associated with decreased recurrence risk and improved survival and quality of life for breast cancer survivors. However, only an estimated 17% to 37% of survivors adhere to the American Cancer Society exercise guidelines. A critical first step to increase exercise among survivors is to understand how they believe exercise will affect them.

OBJECTIVE

The aim of this study is to explore common exercise outcome expectations among 20 female survivors of stage IA to IIB breast cancer who completed adjuvant treatment and an exercise intervention.

METHODS

A mixed-method descriptive study consisting of semistructured telephone interviews assessed exercise outcome expectations and how the experience of cancer and its treatment influenced the expected outcomes of exercise. The qualitative data were analyzed using a summative content analysis procedure; means were calculated for each item of the exercise outcome questionnaire. The qualitative and quantitative data were compared and contrasted.

RESULTS

The sample was 70% white and 30% African American, with a mean (SD) age of 62 (8.5) years, and mean (SD) time since treatment completion of 4.2 (1.3) years. Three themes emerged from the interviews: (1) prevalence of common expectations, (2) pervasive impact of fatigue, and (3) a brighter future. Overall, findings revealed that breast cancer survivors have low levels of agreement that exercise may mitigate late and long-term cancer and treatment effects.

CONCLUSIONS

In general, breast cancer survivors (even those who are motivated to exercise) do not hold strong beliefs that exercise will decrease late and long-term treatment effects.

IMPLICATIONS FOR PRACTICE

Clinicians can educate survivors about exercise benefits.

Cyclophosphamide leads to persistent deficits in physical performance and in vivo mitochondria function in a mouse model of chemotherapy late effects

Fatigue is the symptom most commonly reported by long-term cancer survivors and is increasingly recognized as related to skeletal muscle dysfunction. Traditional chemotherapeutic agents can cause acute toxicities including cardiac and skeletal myopathies. To investigate the mechanism by which chemotherapy may lead to persistent skeletal muscle dysfunction, mature adult mice were injected with a single cyclophosphamide dose and evaluated for 6 weeks. We found that exposed mice developed a persistent decrease in treadmill running time compared to baseline (25.7±10.6 vs. 49.0±16.8 min, P = 0.0012). Further, 6 weeks after drug exposure, in vivo parameters of mitochondrial function remained below baseline including maximum ATP production (482.1 ± 48.6 vs. 696.2 ± 76.6, P = 0.029) and phosphocreatine to ATP ratio (3.243 ± 0.1 vs. 3.878 ± 0.1, P = 0.004). Immunoblotting of homogenized muscles from treated animals demonstrated a transient increase in HNE adducts 1 week after exposure that resolved by 6 weeks. However, there was no evidence of an oxidative stress response as measured by quantitation of SOD1, SOD2, and catalase protein levels. Examination of mtDNA demonstrated that the mutation frequency remained comparable between control and treated groups. Interestingly, there was evidence of a transient increase in NF-ĸB p65 protein 1 day after drug exposure as compared to saline controls (0.091±0.017 vs. 0.053±0.022, P = 0.033). These data suggest that continued impairment in muscle and mitochondria function in cyclophosphamide-treated animals is not linked to persistent oxidative stress and that alternative mechanisms need to be considered.

Dietary Guidelines for Breast Cancer Patients: A Critical Review

Current dietary guidelines for breast cancer patients (BCPs) fail to address adequate dietary intakes of macro- and micronutrients that may improve patients' nutritional status. This review includes information from the PubMed and Biomed Central databases over the last 15 y concerning dietary guidelines for BCPs and the potential impact of a personalized, nutrient-specific diet on patients' nutritional status during and after antineoplastic treatment. Results indicated that BCPs should receive a nutritional assessment immediately after diagnosis. In addition, they should be encouraged to pursue and maintain a healthy body weight [body mass index (BMI; in kg/m²) 20-24.9], preserving their lean mass and avoiding an increase in fat mass. Therefore, after nutritional status diagnosis, a conservative energy restriction of 500-1000 kcal/d could be considered in the dietary intervention when appropriate. Based on the reviewed information, we propose a personalized nutrition intervention for BCPs during and after antineoplastic treatment. Specifications in the nutritional therapy should be based on the patients' nutritional status, dietary habits, schedule, activities, and cultural preferences. BCPs' daily energy intake should be distributed as follows: <30% fat/d (mainly monounsaturated and polyunsaturated fatty acids), ∼55% carbohydrates (primarily whole foods such as oats, brown rice, and fruits), and 1.2-1.5 g protein ⋅ kg^-1 ⋅ d^-1 to avoid sarcopenic obesity. Findings suggest that 5-9 servings/d of fruits (∼150 g/serving) and vegetables (∼75 g/serving) should be encouraged. Garlic and cruciferous vegetables must also be part of the nutrition therapy. Adequate dietary intakes of food-based macro- and micronutrients rich in β-carotene and vitamins A, E, and C can both prevent deterioration in BCPs' nutritional status and improve their overall health and prognosis.

Psychophysical health status of breast cancer survivors and effects of 12 weeks of aerobic training

The aim of this study was to analyse the health status of breast cancer survivors and the effects of 12 weeks of aerobic training. Twenty-three breast cancer survivors (51.71 ± 3.17 years) and 23 healthy women (50.73 ± 2.97 years) were investigated for body composition, daily physical activity, quality of life, salivary cortisol, and DHEA-S. Breast cancer survivors were then aerobically trained for 12 weeks. Breast cancer survivors have a worse psychophysical health than healthy women. Aerobic training increased salivary DHEA-S, aerobic fitness, self-reported health, and nocturnal sleeping time and reduced salivary cortisol in breast cancer survivors. Salivary cortisol variation correlated with change of sleeping time and self-reported health. Salivary DHEA-S correlated with change of self-reported physical pain and general health as well. Breast cancer survivors can live in a situation of continuous distress, requiring a multidisciplinary approach. Twelve weeks of aerobic training improve the psychophysical health of breast cancer survivors.

Impact of Body Weight and Body Composition on Ovarian Cancer Prognosis

Measures of body weight and anthropometrics such as body mass index (BMI) are commonly used to assess nutritional status in clinical conditions including cancer. Extensive research has evaluated associations between body weight and prognosis in ovarian cancer patients, yet little is known about the potential impact of body composition (fat mass (FM) and fat-free mass (FFM)) in these patients. Thus, the purpose of this publication was to review the literature (using PubMed and EMBASE) evaluating the impact of body weight and particularly body composition on surgical complications, morbidity, chemotherapy dosing and toxicity (as predictors of prognosis), and survival in ovarian cancer patients. Body weight is rarely associated with intra-operative complications, but obesity predicts higher rates of venous thromboembolism and wound complications post-operatively in ovarian cancer patients. Low levels of FM and FFM are superior predictors of length of hospital stay compared to measures of body weight alone, but the role of body composition on other surgical morbidities is unknown. Obesity complicates chemotherapy dosing due to altered pharmacokinetics, imprecise dosing strategies, and wide variability in FM and FFM. Measurement of body composition has the potential to reduce toxicity if the results are incorporated into chemotherapy dosing calculations. Some findings suggest that excess body weight adversely affects survival, while others find no such association. Limited studies indicate that FM is a better predictor of survival than body weight in ovarian cancer patients, but the direction of this relationship has not been determined. In conclusion, body composition as an indicator of nutritional status is a better prognostic tool than body weight or BMI alone in ovarian cancer patients.

Preventing weight gain in African American breast cancer survivors using smart scales and activity trackers: a randomized controlled pilot study

PURPOSE

This study evaluated the feasibility and preliminary efficacy of two 6-month, self-regulation interventions that focused on daily self-weighing (DSW) and used objective monitoring and tailored feedback about weight (±activity), to prevent weight gain among African American breast cancer survivors.

METHODS

Participants (n = 35) were randomized to an intervention + activity monitoring (INT+), intervention (INT), or control (CON) group. Interventions included a wireless scale (±activity tracker) that transmitted objective data to a mobile app/website, emailed lessons, and tailored feedback based on objective weight (±activity data). Participants completed in-person and online assessments at baseline, 3 months, and 6 months.

RESULTS

Ninety-four percent of participants completed assessments at 3 months, and 97 % at 6 months. Median (IQR) weight change after 6 months was -0.9 % (-4.4-0.1) in the INT+ (p = 0.075; p = 0.067 vs. CON) and -0.2 % (-4.2-1.3) in the INT groups (p = 0.463; p = 0.357 vs. CON), versus a 0.2 % (-0.7-1.7) gain in the CON group. The proportion of INT+, INT, and CON participants that were at or below baseline weight was 72.7, 53.8, and 45.5 %, respectively (effect sizes d = 0.64, d = 0.18). Most INT+ participants weighed and wore trackers ≥5 days/week (INT+, 81.9 % vs. INT, 38.5 % vs. CON, 0 %; p < 0.0005; INT+, 72.7 %). Both intervention groups perceived DSW as positive, and 100 % would recommend the program to other breast cancer survivors.

CONCLUSION

An intervention focused on DSW as a self-monitoring strategy shows promise for preventing weight gain in breast cancer survivors.

IMPLICATIONS FOR CANCER SURVIVORS

Daily self-monitoring of weight and activity may be a feasible and accessible approach to promote weight gain prevention in breast cancer survivors.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov, NCT02030353.

Industry is not the dark side, but an essential partner to make progress in reproductive health

For the last 20 years, Thomas D'Hooghe has been coordinator of the Leuven University Fertility Center at Leuven University Hospitals, Belgium, one of the largest teaching hospitals in Europe. Since 1995, he has also been Professor of Reproductive Medicine and Biology at KU Leuven (University of Leuven) and Adjunct Professor at Yale University, USA. Since 1 October 2015, he has been the Vice President and Head of Global Medical Affairs Fertility at Merck's headquarters in Darmstadt, Germany. He has published nearly 300 papers in internationally peer-reviewed journals and has contributed to reproductive health serving major international organizations such as the WHO, the European Society of Human Reproduction and Embryology, the Society of Reproductive Investigation and the World Endometriosis Research Foundation.

Obesity and Breast Cancer

The relationship between adiposity and breast cancer risk and prognosis is complex, with associations that differ depending on when body size is assessed (e.g., pre- vs. postmenopausal obesity) and when breast cancer is diagnosed (i.e., pre- vs. postmenopausal disease). Further, the impact of obesity on risk differs by tumor hormone receptor status (e.g., estrogen (ER) and progesterone (PR) receptor) and, among postmenopausal women, use of exogenous hormones (i.e., hormone replacement therapy (HRT)). In the context of these complexities, this review focuses on associations between childhood and adolescent adiposity, general adiposity, weight changes (i.e., loss and gain), abdominal adiposity, and breast cancer risk and survival. Finally, we discuss potential mechanisms linking adiposity to breast cancer.

Weight Gain After Breast Cancer Diagnosis and All-Cause Mortality: Systematic Review and Meta-Analysis

BACKGROUND

Overweight and obesity are associated with breast cancer mortality. However, the relationship between postdiagnosis weight gain and mortality is unclear. We conducted a systematic review and meta-analysis of weight gain after breast cancer diagnosis and breast cancer-specific, all-cause mortality and recurrence outcomes.

METHODS

Electronic databases identified articles up through December 2014, including: PubMed (1966-present), EMBASE (1974-present), CINAHL (1982-present), and Web of Science. Language and publication status were unrestricted. Cohort studies and clinical trials measuring weight change after diagnosis and all-cause/breast cancer-specific mortality or recurrence were considered. Participants were women age 18 years or older with stage I-IIIC breast cancer. Fixed effects analysis summarized the association between weight gain (≥5.0% body weight) and all-cause mortality; all tests were two-sided.

RESULTS

Twelve studies (n = 23 832) were included. Weight gain (≥5.0%) compared with maintenance (<±5.0%) was associated with increased all-cause mortality (hazard ratio [HR] = 1.12, 95% confidence interval [CI] = 1.03 to 1.22, P = .01, I(2) = 55.0%). Higher risk of mortality was apparent for weight gain ≥10.0% (HR = 1.23, 95% CI = 1.09 to 1.39, P < .001); 5% to 10.0% weight gain was not associated with all-cause mortality (P = .40). The association was not statistically significant for those with a prediagnosis body mass index (BMI) of less than 25 kg/m(2) (HR = 1.14, 95% CI = 0.99 to 1.31, P = .07) or with a BMI of 25 kg/m(2) or higher (HR = 1.00, 95% CI = 0.86 to 1.16, P = .19). Weight gain of 10.0% or more was not associated with hazard of breast cancer-specific mortality (HR = 1.17, 95% CI = 1.00 to 1.38, P = .05).

CONCLUSIONS

Weight gain after diagnosis of breast cancer is associated with higher all-cause mortality rates compared with maintaining body weight. Adverse effects are greater for weight gains of 10.0% or higher.

Tamoxifen affects glucose and lipid metabolism parameters, causes browning of subcutaneous adipose tissue and transient body composition changes in C57BL/6NTac mice

Tamoxifen is a selective estrogen receptor (ER) modulator which is widely used to generate inducible conditional transgenic mouse models. Activation of ER signaling plays an important role in the regulation of adipose tissue (AT) metabolism. We therefore tested the hypothesis that tamoxifen administration causes changes in AT biology in vivo. 12 weeks old male C57BL/6NTac mice were treated with either tamoxifen (n = 18) or vehicle (n = 18) for 5 consecutive days. Tamoxifen treatment effects on body composition, energy homeostasis, parameters of AT biology, glucose and lipid metabolism were investigated up to an age of 18 weeks. We found that tamoxifen treatment causes: I) significantly increased HbA1c, triglyceride and free fatty acid serum concentrations (p < 0.01), II) browning of subcutaneous AT and increased UCP-1 expression, III) increased AT proliferation marker Ki67 mRNA expression, IV) changes in adipocyte size distribution, and V) transient body composition changes. Tamoxifen may induce changes in body composition, whole body glucose and lipid metabolism and has significant effects on AT biology, which need to be considered when using Tamoxifen as a tool to induce conditional transgenic mouse models. Our data further suggest that tamoxifen-treated wildtype mice should be characterized in parallel to experimental transgenic models to control for tamoxifen administration effects.

Assessing the prevalence of compromised bone health among overweight and obese African-American breast cancer survivors: a case-control study

PURPOSE

Osteoporosis increases the risk of fracture and is often considered a late effect of breast cancer treatment. We examined the prevalence of compromised bone health in a sample of exclusively African-American (AA) breast cancer survivors since bone mineral density (BMD) varies by race/ethnicity in healthy populations.

METHODS

Using a case-control design, AA women in a weight loss intervention previously diagnosed and treated for stages I-IIIa breast cancer were matched 1:1 on age, race, sex, and BMI with non-cancer population controls (n = 101 pairs) from National Health and Nutrition Examination Survey (NHANES). Questionnaires and dual-energy x-ray absorptiometry (DXA) scanning were completed, and participants were categorized as having normal bone density, low bone mass, or osteoporosis using the World Health Organization (WHO) definition for femoral neck T-scores.

RESULTS

The majority of these overweight/obese survivors were 6.6 (±4.7) years post-diagnosis, had stage II (n = 46) or stage III (n = 16) disease, and treated with chemotherapy (76 %), radiation (72 %), and/or adjuvant hormone therapies (45 %). Mean femoral neck BMD was significantly lower in cases vs. matched non-cancer population controls (0.85 ± 0.15 vs. 0.91 ± 0.14 g/cm(2), respectively; p = 0.007). However, the prevalence of low bone mass and osteoporosis was low and did not significantly differ between groups (n = 101 pairs; p = 0.26), even when restricted to those on adjuvant hormone therapies (n = 45 pairs; p = 0.75). Using conditional logistic regression, controlling for dietary factors and education, the odds of developing compromised bone health in AA breast cancer survivors was insignificant (OR 1.5, 95 % CI 0.52, 5.56).

CONCLUSIONS

These null case-control findings challenge the clinical assumption that osteoporosis is highly prevalent among all breast cancer survivors, providing foundational evidence to support differences by race/ethnicity and body weight.

IMPLICATIONS FOR CANCER SURVIVORS

Routine bone density testing and regular patient-provider dialogue is critical in overweight/obese AA breast cancer survivors to ensure that healthy lifestyle factors (e.g., ideal weight, regular weight-bearing exercises, dietary adequacy of calcium and vitamin D) support optimal skeletal health.

The muscle mass, omega-3, diet, exercise and lifestyle (MODEL) study - a randomised controlled trial for women who have completed breast cancer treatment

Background

Loss of lean body mass (LBM) is a common occurrence after treatment for breast cancer and is related to deleterious metabolic health outcomes [Clin Oncol, 22(4):281–288, 2010; Appl Physiol Nutr Metab, 34(5):950–956, 2009]. The aim of this research is to determine the effectiveness of long chain omega-3 fatty acids (LCn-3s) and exercise training alone, or in combination, in addressing LBM loss in breast cancer survivors.

Methods/design

A total of 153 women who have completed treatment for breast cancer in the last 12 months, with a Body Mass Index (BMI) of 20 to 35 kg/m², will be randomly assigned to one of 3 groups: 3g/d LCn-3s (N-3), a 12-week nutrition and exercise education program plus olive oil (P-LC) or the education program plus LCn-3s (EX+N-3). Participants randomised to the education groups will be blinded to treatment, and will receive either olive oil placebo (OO+N-3) or LCn-3 provision, while the N-3 group will be open label. The education program includes nine 60-75min sessions over 12 weeks that will involve breast cancer specific healthy eating advice, plus a supervised exercise session run as a resistance exercise circuit. They will also be advised to conduct the resistance training and aerobic training 5 to 7 days per week collectively. Outcome measures will be taken at baseline, 12-weeks and 24-weeks. The primary outcome is % change in LBM as measured by the air displacement plethysmograhy. Secondary outcomes include quality of life (FACT-B + 4) and inflammation (C-Reactive protein: CRP). Additional measures taken will be erythrocyte fatty acid analysis, fatigue, physical activity, menopausal symptoms, dietary intake, joint pain and function indices.

Discussion

This research will provide the first insight into the efficacy of LCn-3s alone or in combination with exercise in breast cancer survivors with regards to LBM and quality of life. In addition, this study is designed to improve evidence-based dietetic practice, and how specific dietary prescription may link with appropriate exercise interventions.

Trials registration

ACTRN12610001005044; and World Health Organisation Universal trial number: U1111-1116-8520.

Muscle function and omega-3 fatty acids in the prediction of lean body mass after breast cancer treatment

Background

Decreased lean body mass (LBM) is common in breast cancer survivors yet currently there is a lack of information regarding the determinants of LBM after treatment, in particular, the effect of physical activity and dietary factors, such as long-chain omega-3 fatty acids (LCn-3) on LBM and LBM function. This cross-sectional study explored associations of LBM and function with LCn-3 intake, dietary intake, inflammation, quality of life (QOL) and physical fitness in breast cancer survivors to improve clinical considerations when addressing body composition change.

Methods

Forty-nine women who had completed treatment (surgery, radiation and/or chemotherapy) were assessed for body composition (BODPOD), LCn-3 content of erythrocytes, C-reactive protein (CRP), QOL, dietary intake, objective physical activity, 1-min push-ups, 1-min sit-stand, sub-maximal treadmill (TM) test, and handgrip strength.

Results

After adjustment for age, LBM was associated with push-ups (r = 0.343, p = 0.000), stage reached on treadmill (StageTM) (r = 0.302, 0.001), % time spent ≥ moderate activity (Mod + Vig) (r = 0.228, p = 0.024). No associations were seen between anthropometric values and any treatment, diagnostic and demographical variables. Body mass, push-ups and StageTM accounted for 76.4% of the variability in LBM (adjusted r-square: 0.764, p = 0.000). After adjustment docosahexanoic acid (DHA) was positively associated with push-ups (β=0.399, p = 0.001), eicosapentanoic acid (EPA) was negatively associated with squats (r = −0.268, p = 0.041), with no other significant interactions found between LCn-3 and physical activity for LBM or LBM function.

Conclusion

This is the first investigation to report that a higher weight adjusted LBM is associated with higher estimated aerobic fitness and ability to perform push-ups in breast cancer survivors. Potential LCn-3 and physical activity interactions on LBM require further exploration.

Disentangling the body weight-bone mineral density association among breast cancer survivors: an examination of the independent roles of lean mass and fat mass

BACKGROUND

Bone mineral density (BMD) and lean mass (LM) may both decrease in breast cancer survivors, thereby increasing risk of falls and fractures. Research is needed to determine whether lean mass (LM) and fat mass (FM) independently relate to BMD in this patient group.

METHODS

The Health, Eating, Activity, and Lifestyle Study participants included 599 women, ages 29-87 years, diagnosed from 1995-1999 with stage 0-IIIA breast cancer, who underwent dual-energy X-ray absorptiometry scans approximately 6-months postdiagnosis. We calculated adjusted geometric means of total body BMD within quartiles (Q) of LM and FM. We also stratified LM-BMD associations by a fat mass index threshold that tracks with obesity (lower body fat: ≤ 12.9 kg/m2; higher body fat: >12.9 kg/m2) and stratified FM-BMD associations by appendicular lean mass index level corresponding with sarcopenia (non-sarcopenic: ≥ 5.45 kg/m2 and sarcopenic: < 5.45 kg/m2).

RESULTS

Higher LM (Q4 vs. Q1) was associated with higher total body BMD overall (1.12 g/cm2 vs. 1.07 g/cm2, p-trend  < 0.0001), and among survivors with lower body fat (1.13 g/cm2 vs. 1.07 g/cm2, p-trend < 0.0001) and higher body fat (1.15 g/cm2 vs. 1.08 g/cm2, p-trend = 0.004). Higher FM (Q4 vs. Q1) was associated with higher total body BMD overall (1.12 g/cm2 vs. 1.07 g/cm2, p-trend < 0.0001) and among non-sarcopenic survivors (1.15 g/cm2 vs. 1.08 g/cm2, p < 0.0001), but the association was not significant among sarcopenic survivors (1.09 g/cm2 vs. 1.04 g/cm2, p-trend = 0.18).

CONCLUSION

Among breast cancer survivors, higher LM and FM were independently related to higher total body BMD. Future exercise interventions to prevent bone loss among survivors should consider the potential relevance of increasing and preserving LM.

Body fatness and breast cancer risk in women of African ancestry

BACKGROUND

Obesity has been shown to be inversely associated with breast cancer risk in premenopausal women, while increasing risk in postmenopausal women. However, the current evidence is largely based on studies in Caucasian populations. Associations in women of African ancestry (AA), who have a higher prevalence of obesity, have been evaluated in few studies and results suggest different effects.

METHODS

We evaluated the impact of body size, body fat distribution, and body composition on breast cancer risk among AA women (978 cases and 958 controls) participating in the Women's Circle of Health Study, a multi-site case-control study in New York City (NYC) and New Jersey (NJ). Cases were newly diagnosed with histologically confirmed ductal carcinoma in situ or invasive breast cancer, age 20-75 yrs. In NYC, cases were recruited through hospitals with the largest referral patterns for AA women and controls through random digit dialing (RDD). In NJ, cases were identified in seven counties in NJ thorough the NJ State Cancer Registry, and controls through RDD and community-based recruitment. During in-person interviews, questionnaires were administered and detailed anthropometric measurements were obtained. Body composition was assessed by bioelectrical impedance analysis.

RESULTS

BMI did not have a major impact on pre- or post-menopausal breast cancer, but was significantly associated with reduced risk of ER-/PR- tumors among postmenopausal women (OR: 0.37; 95% CI: 0.15-0.96 for BMI > 30 vs. BMI < 25). Furthermore, increased premenopausal breast cancer risk was found for higher waist and hip circumferences after adjusting for BMI, with ORs of 2.25 (95% CI: 1.07-4.74) and 2.91 (95% CI: 1.39-6.10), respectively, comparing the highest vs. lowest quartile. While ORs for higher fat mass and percent body fat among postmenopausal women were above one, confidence intervals included the null value.

CONCLUSIONS

Our study suggests that in AA women BMI is generally unrelated to breast cancer. However, higher waist and hip circumferences were associated with increased pre-menopausal breast cancer risk, while general obesity was associated with decreased risk of ER-/PR- tumors. Larger studies are needed to confirm findings and to evaluate the impact of obesity on breast cancer subtypes.

The effect of progressive resistance training on lean body mass in post-treatment cancer patients - a systematic review

Loss of lean body mass is a common problem in many post-treatment cancer patients and may negatively affect physical capacity in terms of maximal muscle strength and functional performance. The purpose of this study was to systematically review the scientific evidence on the effect of progressive resistance training on lean body mass in post-treatment cancer patients. A comprehensive literature search was conducted and ultimately 12 studies were included. Methodological quality of the included studies was evaluated using the PEDro scale and the effect of progressive resistance training was reported as the range of mean changes among RCTs and non-RCTs. Six RCTs and six non-RCTs were included in the study. In the RCTs the change in lean body mass in the progressive resistance training groups relative to control groups ranged from -0.4% to 3.9%, and in four of six trials the training effect was significantly larger than the change in the control groups. In the six non-RCTs, the mean change in lean body mass over time ranged from -0.01 to 11.8% which was significant in two of the trials. The included studies reported no or very limited adverse events following progressive resistance training. Based on 12 heterogenic studies there is moderate evidence supporting a positive effect of progressive resistance training on lean body mass in post-treatment cancer patients.