Physical activity and breast cancer: review of the epidemiologic evidence and biologic mechanisms

Physical Activity during Adolescence and Early Adulthood and Breast Cancer Risk before Age 40 Years

BACKGROUND

Breast cancer incidence is increasing in women under age 40, underscoring the need for research on breast cancer risk factors for younger women.

METHODS

We used data from an international family cohort (n = 26,348) to examine whether recreational physical activity (RPA) during adolescence and early adulthood is associated with breast cancer risk before age 40. The cohort includes 2,502 women diagnosed with breast cancer before age 40, including 2,408 diagnosed before study enrollment (68% within 5 years of enrollment). Women reported their average hours per week of moderate and strenuous RPA during adolescence (12-17 years) and early adulthood (25-34 years), which were converted to total age-adjusted metabolic equivalents per week and categorized into quartiles. We conducted attained age analyses until age 40 (follow-up time began at age 18) using Cox proportional hazards regression models adjusted for study center, race and ethnicity, and education.

RESULTS

Being in the highest versus lowest quartile of RPA during adolescence and early adulthood were respectively associated with 12% [HR (95% confidence interval, or CI), 0.88 (0.78-0.98)] and 16% [HR (95% CI), 0.84 (0.74-0.95) lower breast cancer risks before age 40. Being in the highest quartile of RPA during both adolescence and early adulthood (Pearson correlation = 0.52) versus neither time point was associated with a 22% lower risk [HR (95% CI), 0.78 (0.68-0.89)].

CONCLUSIONS

Findings suggest that RPA during adolescence and early adulthood may lower breast cancer risk before age 40.

IMPACT

Policies promoting physical activity during adolescence and early adulthood may be important for reducing the growing burden of breast cancer in younger women.

The Association Between Physical Activity and risk for breast cancer in US female adults: A cross-sectional study based on NHANES 2011-2020

BACKGROUND

Breast cancer poses a significant threat to women's health worldwide. This study aimed to evaluate the association between various levels of physical activity and the incidence of breast cancer.

METHODS

The data for this study were obtained from the National Health and Nutrition Examination Survey (NHANES), spanning 2011 to 2020. The study included female participants aged 20 years or older, who provided detailed data on breast cancer incidence, physical activity levels, and other pertinent variables. Adjusted odds ratios (ORs) and 95 % confidence intervals (CIs) were calculated using multivariate logistic regression analyses, alongside subgroup and sensitivity analyses.

RESULTS

After adjusting for potential confounders, multivariate logistic regression analyses indicated that compared to individuals with low physical activity (<600 METs min/week), light physical activity (600 to < 1800 METs min/week), moderate physical activity (1800 to < 3000 METs min/week) and high physical activity (≥3000 METs min/week) were associated with breast cancer with adjusted ORs of 0.95 (95 % CI 0.68-1.34, P = 0.787), 0.92 (95 % CI 0.57-1.49, P = 0.747), and 0.56 (95 % CI 0.37-0.86, P = 0.009) respectively. These results were consistent across sensitivity and subgroup analyses.

CONCLUSION

High-intensity physical activity may decrease the risk of breast cancer, highlighting the importance of proactively implementing healthy lifestyle interventions to protect the health of adult women.

Social Representativeness and Intervention Adherence-A Systematic Review of Clinical Physical Activity Trials in Breast Cancer Patients

Objectives

Representativeness in physical activity randomised controlled trials (RCT) in breast cancer patients is essential to analyses of feasibility and validity considering privileged- social groups. A step-by-step exclusion of less privileged groups through the trial process could reinforce health inequality. This study aimed at examining representativeness in breast cancer (BC) physical activity trials, investigate associations between socio-economic status (SES) and intervention adherence, and explore associations between representativeness and the relationship between SES and intervention adherence.

Methods

Systematic, computerised searches were performed in PubMed, CINAHL, AMED, EMBASE and PsycINFO. Additional citation-based searches retrieved 37 articles. Distributions of education level, ethnicity, and marital status in study samples were compared to national populations data to estimate representativeness in less privileged groups.

Results

A preponderance of studies favoured educated, married and white patients. Only six studies reported SES-adherence associations, hampering conclusions on this relationship and possible associations between representativeness and an SES-adherence relationship.

Conclusion

Less educated, unmarried and non-white individuals may be underrepresented in BC physical activity RCTs, while SES-adherence associations in such trials are inconclusive. Unintentional social misrepresentations may indicate that disguised inequity warrants revived attention.

[How could physical activity decrease the risk of breast cancer development and recurrence?]

OBJECTIVES

Breast cancer is the most frequent and deadly cancer among women. In France, 50% of adults are currently overweight, mostly as a result of a sedentary lifestyle. Numerous studies have highlighted overweight, obesity and lack of physical activity as risk factors for the occurrence and prognosis of cancers, particularly breast cancer. The aim of this study was to understand the extent to which physical activity can improve this prognosis, and what the pathophysiology is.

METHODS

The Senology Commission of the Collège national des gynécologues et obstétriciens français (CNGOF) based its responses on an analysis of the international literature using a Preferred Reporting Items for Systematic review and Meta-Analyses (PRISMA) methodology conducted on the PubMed database between 1994 and 2023.

RESULTS

A total of 70 articles were selected, demonstrating the role of regular physical activity in reducing the risk of breast cancer occurrence and recurrence. This role in controlling carcinogenesis is mediated by metabolic factors such as leptin, adiponectin and insulin, sex hormones and inflammation. The signaling pathways deregulated by these molecules are known carcinogenic pathways which could be used as therapeutic targets adapted to this population, without replacing the essential hygienic-dietary recommendations.

CONCLUSION

Physical activity has a protective effect on breast cancer risk and prognosis. We must therefore continue to raise awareness in the general population and promote physical activity as a means of primary, secondary, and tertiary prevention.

The protective effect of endurance running against the pro-invasive effects of ageing in breast cancer cells and mesenchymal stem cells in vitro

Purpose

Regular exercise is known to reduce cancer risk and may prevent metastases, however, modelling this in vitro is challenging due the heterogeneity of the tumour microenvironment. Exercised serum can be used to capture changes in cellular signalling components in response to different types and durations of exercise. In this study, exercised serum from long-term endurance runners and sprinters of different ages was used to evaluate the impact of exercise on the invasiveness of breast cancer cells and mesenchymal stem cells in vitro.

Methods

Exercised serum from long-term trained younger and older endurance runners and sprinters was used to supplement cell culture media in the 3D culture of spheroids containing breast cancer cells or mesenchymal stem cells. Spheroids were generated in a 3D semi-solid matrix and cell invasion was measured using ImageJ software. Statistical analyses of invasion were conducted using one-way ANOVAs.

Results

Invasion was significantly greater in cells cultured with serum from older, inactive participants compared to young, inactive participants (YC vs OC; F (1,3) = 37.135, P = 0.009). No significant difference was found in the invasion of MDA-MB-231 breast cancer cells cultured in serum from older, long-term endurance runners and younger, long-term endurance runners (YE vs OE; F (1,3) = 5.178, P = 0.107), suggesting a protective effect of endurance running against the pro-invasive effects of ageing.

Conclusion

This is the first study of its kind to demonstrate the protective effects of long-term exercise training type in two populations of different ages against the invasiveness of breast cancer cells in vitro.

Association of food groups and dietary pattern with breast cancer risk: A systematic review and meta-analysis

BACKGROUND & AIMS

We conducted a systematic review and meta-analysis of current evidence for the association between food groups, dietary patterns, and breast cancer risk among the Asian population.

METHODS

This systematic review and meta-analysis followed the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines. We performed a systematic literature search up to December 2022 in English in the PubMed, Web of Science, Embase, and Cochrane databases. Risk ratios (RRs) with 95% confidence intervals (CIs) were extracted as effect sizes. Publication bias was estimated by two different funnel plot methods.

RESULTS

We collected the data from 15 cohort studies and 34 case-control studies meeting the search criteria. The meta-analysis found that the consumption of fruits and, likewise, vegetables were associated with a 29% lower risk of breast cancer, respectively [RR = 0.71 (0.55, 0.93); RR = 0.71 (0.53, 0.95)]. By contrast, no significance was found between meat, soy foods, and green tea consumption and breast cancer risk (P > 0.05). However, soy protein and isoflavone intake could lower breast cancer risk by 35% and 32%, respectively [RR = 0.65 (0.51, 0.83); RR = 0.68 (0.55, 0.82)]. As for the dietary pattern, high adherence to a healthy dietary pattern and, similarly, to a healthy eating index was associated with a 38% and 51% reduction in breast cancer risk, respectively [RR = 0.62 (0.44, 0.88; RR = 0.49 (0.27, 0.87)], while high adherence to an unhealthy dietary pattern was associated with a 44% increased risk [RR = 1.44 (1.06, 1.96)]. Considering alcohol consumption, a 75% increased risk of breast cancer was found [RR = 1.75 (1.33, 2.30)].

CONCLUSION

The present meta-analysis found that high intakes of fruits, vegetables, soy protein, and soy isoflavone significantly reduced the risk of breast cancer, while high intake of alcohol had a significantly increased risk. Meat, soy food, and green tea consumption were not significantly associated with breast cancer risk. Considering dietary patterns, high adherence to a healthy eating index and a healthy dietary pattern may reduce breast cancer risk. Conversely, adherence to unhealthy dietary patterns may increase breast cancer risk. However, further studies are needed to confirm the associations between dietary patterns and breast cancer in the Asian population.

Developing practice guidelines to integrate physical activity promotion as part of routine cancer care: A knowledge-to-action protocol

Background

Cancer is a leading cause of disease burden worldwide and the first cause of mortality in Canada with 30.2% of deaths attributable to cancer. Given aging of the population and the improvement of prevention and treatment protocols, the number of cancer survivors is steadily increasing. These individuals have unique physical and mental health needs some of which can be addressed by integrating physical activity promotion into ongoing and long-term care. Despite the benefits of being active, delivery of PA programs for cancer patients in both clinical and community settings remains challenging. This knowledge-to-action protocol–called Kiné-Onco–aims to develop a practice guideline for the delivery, implementation, and scaling-up of cancer-specific physical activity promotion programs and services in clinical and community settings located in Québec, Canada.

Method

The Kiné-Onco project involves knowledge synthesis of scientific and grey literature to establish the benefits and added value of physical activity for cancer patients and survivors, describes current practices in delivering physical activity programs, analyses quantitative data from electronic health records (EHR) of patients participating in a novel hospital-based physical activity program, collects and analyses qualitative data from patients and healthcare providers interviews about lived experience, facilitators, and barriers to physical activity promotion, outlines deliberative workshops among multidisciplinary team members to develop implementation guidelines for physical activity promotion, and summarizes a variety of knowledge transfer and exchange activities to disseminate the practice guidelines.

Discussion

This paper describes the protocol for a knowledge-to-action project aimed at producing and sharing actionable evidence. Our aim is that physical activity promotion programs and services be scaled up in such a way as to successfully integrate physical activity promotion throughout cancer treatment and survivorship in order to improve the physical and mental health of the growing population of individuals having received a cancer diagnosis.

Factors predicting long-term physical activity of breast cancer survivors. 5-year-follow-up of the BREX exercise intervention study

BACKGROUND

The benefits of exercise training are well documented among breast cancer (BC) survivors. Patients decrease their physical activity during treatment, and many fail to regain their previous exercise levels. There is therefore a need to define factors supporting long-term physical activity behavior in this patient group, to target supporting interventions aimed at preventing the decline in physical activity (PA).

AIM

The aim of this study was to determine physical and psychosocial factors explaining long-term physical activity after the adjuvant treatments in BC survivors.

METHODS

Four-hundred forty-six BC survivors followed for 5-years within a randomized exercise trial participated. Factors explaining (1) physical activity after the adjuvant treatments and (2) changes in physical activity in long-term were analyzed using linear regression models and general estimating equation models. Pretreatment leisure-time physical activity (LTPA), demographic, and treatment factors, physical fitness, and quality of life (Qol) at baseline were independent factors.

RESULTS

Exercise levels increased during the first year, and thereafter remained mostly stable. Higher LTPA, higher fitness level, better Qol and older age at baseline were associated with higher physical activity level after adjuvant treatments (p < .001) in multivariate analysis. Higher levels of fatigue (p < .008) and better emotional functioning (p = .017) at baseline were the main factors associated with increased physical activity during the follow-up.

CONCLUSION

Previous exercise habits and Qol after adjuvant chemo-, and radiotherapy were the strongest determinants of long-term physical activity levels in breast cancer survivors. Patients with better emotional functioning increased their exercise activity most as did those patients with higher fatigue levels at baseline. Patients suffering from fatigue after adjuvant treatment managed to increase their exercise levels, in contrast to patients with low emotional functioning, and may benefit from physical exercise interventions. Emotionally deprived patients may benefit from psychosocial support to regain their previous exercise levels.

Cytotoxic Evaluation, Molecular Docking, and 2D-QSAR Studies of Dihydropyrimidinone Derivatives as Potential Anticancer Agents

The diverse pharmacological role of dihydropyrimidinone scaffold has made it to be an interesting drug target. Because of the high incidence and mortality rate of breast cancer, there is a dire need of discovering new pharmacotherapeutic agents in managing this disease. A series of twenty-two derivatives of 6-(chloromethyl)-4-(4-hydroxyphenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (3a-3k) and ethyl 6-(chloromethyl)-4-(2-hydroxyphenyl)-2-oxo-1,2,3,4-tetrahydropyrimidine-5-carboxylate (4a-4k) synthesized in a previous study were evaluated for their anticancer potential against breast cancer cell line. Molecular docking studies were performed to analyze the binding mode and interaction pattern of these compounds against nine breast cancer target proteins. The in vitro cell proliferation assay was performed against the breast cancer cell line MCF-7. The structure activity relationship of these compounds was further studied using QSARINS. Among nine proteins, the docking analysis revealed efficient binding of compounds 4f, 4e, 3e, 4g, and 4h against all target proteins. The in vitro cytotoxic assay revealed significant anticancer activity of compound 4f having $\text{I}{\text{C}}_{50}$ of 2.15 μM. The compounds 4e, 3e, 4g, and 4h also showed anticancer activities with $\text{I}{\text{C}}_{50}$ of 2.401, 2.41, 2.47 and 2.33 μM, respectively. The standard tamoxifen showed $\text{I}{\text{C}}_{50}$ 1.88 μM. The 2D qualitative structure-activity relationship (QSAR) analysis was also carried out to identify potential breast cancer targets through QSARINS. The final QSAR equation revealed good predictivity and statistical validation $R^2$ and $Q^2$ values for the model obtained from QSARINS was 0.98 and 0.97, respectively. The active compounds showed very good anticancer activities, and the binding analysis has revealed stable hydrogen bonding of these compounds with the target proteins. Moreover, the QSAR analysis has predicted useful information on the structural requirement of these compounds as anticancer agents with the importance of topological and autocorrelated descriptors in effecting the cancer activities.

Mechanobiology of Bone Metastatic Cancer

PURPOSE OF REVIEW

In this review, we provide an overview of what is currently known about the impacts of mechanical stimuli on metastatic tumor-induced bone disease (TIBD). Further, we focus on the role of the osteocyte, the skeleton's primary mechanosensory cell, which is central to the skeleton's mechanoresponse, sensing and integrating local mechanical stimuli, and then controlling the downstream remodeling balance as appropriate.

RECENT FINDINGS

Exercise and controlled mechanical loading have anabolic effects on bone tissue in models of bone metastasis. They also have anti-tumorigenic properties, in part due to offsetting the vicious cycle of osteolytic bone loss as well as regulating inflammatory signals. The impacts of metastatic cancer on the mechanosensory function of osteocytes remains unclear. Increased mechanical stimuli are a potential method for mitigating TIBD.

Increased Use of Porch or Backyard Nature during COVID-19 Associated with Lower Stress and Better Symptom Experience among Breast Cancer Patients

Contact with nature has been used to promote both physical and mental health, and is increasingly used among cancer patients. However, the COVID-19 pandemic created new challenges in both access to nature in public spaces and in cancer care. The purpose of our study was to evaluate the change in active and passive use of nature, places of engaging with nature and associations of nature contact with respect to improvements to perceived stress and symptom experience among breast cancer patients during the pandemic. We conducted a cross-sectional survey of people diagnosed with breast cancer using ResearchMatch (n = 56) in July 2020 (the first wave of COVID-19). In this US-based, predominantly white, affluent, highly educated, female sample, we found that, on average, participants were first diagnosed with breast cancer at 54 years old and at stage 2 or 3. Eighteen percent of participants experienced disruptions in their cancer care due to the pandemic. As expected, activities in public places significantly decreased as well, including use of parks/trails and botanical gardens. In contrast, spending time near home, on the porch or in the backyard significantly increased. Also observed were significant increases in indoor activities involving passive nature contact, such as watching birds through a window, listening to birdsong, and smelling rain or plants. Decreased usage of parks/trails was significantly associated with higher stress (Coef = -2.30, p = 0.030) and increased usage of the backyard/porch was significantly associated with lower stress (Coef = -2.69, p = 0.032), lower symptom distress (Coef = -0.80, p = 0.063) and lower symptom severity (Coef = -0.52, p = 0.009). The most commonly reported alternatives to outdoor engagement with nature were watching nature through a window (84%), followed by looking at images of nature (71%), and listening to nature through a window (66%). The least commonly enjoyed alternative was virtual reality of nature scenes (25%). While outdoor contact with nature away from home decreased, participants still found ways to experience the restorative benefits of nature in and around their home. Of special interest in planning interventions was the fact that actual or real nature was preferred over that experienced through technology. This could be an artifact of our sample, or could represent a desire to be in touch with the "real world" during a health crisis. Nature contact may represent a flexible strategy to decrease stress and improve symptom experience among patients with cancer, particularly during public health crises or disruptions to cancer care.

Run for your life: an integrated virtual tissue platform for incorporating exercise oncology into immunotherapy

The purpose of this paper is to introduce a novel in silico platform for simulating early-stage solid tumor growth and anti-tumor immune response. We present the model, test the sensitivity and robustness of its parameters, and calibrate it with clinical data from exercise oncology experiments which offer a natural biological backdrop for modulation of anti-tumor immune response. We then perform two virtual experiments with the model that demonstrate its usefulness in guiding pre-clinical and clinical studies of immunotherapy. The first virtual experiment describes the intricate dynamics in the tumor microenvironment between the tumor and the infiltrating immune cells. Such dynamics is difficult to probe during a pre-clinical study as it requires significant redundancy in lab animals and is prohibitively time-consuming and labor-intensive. The result is a series of spatiotemporal snapshots of the tumor and its microenvironment that can serve as a platform to test mechanistic hypotheses on the role and dynamics of different immune cells in anti-tumor immune response. The second virtual experiment shows how dosage and/or frequency of immunotherapy drugs can be optimized based on the aerobic fitness of the patient, so that possible adverse side effects of the treatment can be minimized.

Precursor fractions of neurotensin and enkephalin might point to molecular mechanisms of cancer risk modulation during a lifestyle-intervention in germline BRCA1/2 gene mutation carriers

BACKGROUND

Germline BRCA1/2 mutation carriers (gBMC) face increased cancer risks that are modulated via non-genetic lifestyle factors whose underlying molecular mechanisms are unknown. The peptides Neurotensin (NT) and Enkephalin (ENK)-involved in tumorigenesis and obesity-related diseases-are of interest. We wanted to know whether these biomarkers differ between gBMC and women from the general population and what effect a 1-year lifestyle-intervention has in gBMC.

METHODS

The stable precursor fragments pro-NT and pro-ENK were measured at study entry (SE), after 3 and 12 months for 68 women from LIBRE-1 (a controlled lifestyle-intervention feasibility trial for gBMC involving structured endurance training and the Mediterranean Diet). The SE values were compared with a cohort of the general population including female subjects with and without previous cancer disease, non-suggestive for hereditary breast and ovarian cancer (OMA-reference). For LIBRE-1, we analysed the association between the intervention-related change in the two biomarkers and certain lifestyle factors.

RESULTS

At SE, gBMC had a higher median pro-NT than OMA-reference (in the subgroups with previous cancer 117 vs. 91 pmol/L, p = 0.002). Non-diseased gBMC had lower median pro-ENK levels when compared to the non-diseased reference group. VO2peak and pro-NT 1-year change in LIBRE-1 were inversely correlated (r = - 0.435; CI - 0.653 to - 0.151; p = 0.004). Pro-ENK correlated positively with VO2peak at SE (r = 0.323; CI 0.061-0.544; p = 0.017). Regression analyses showed an inverse association of 1-year changes for pro-NT and Omega-6/Omega-3 (Estimate: - 37.9, p = 0.097/0.080) in multivariate analysis.

CONCLUSION

Our results give first indications for lifestyle-related modification particularly of pro-NT in gBMC.

Genome-scale meta-analysis of breast cancer datasets identifies promising targets for drug development

Background

Because of the highly heterogeneous nature of breast cancer, each subtype differs in response to several treatment regimens. This has limited the therapeutic options for metastatic breast cancer disease requiring exploration of diverse therapeutic models to target tumor specific biomarkers.

Methods

Differentially expressed breast cancer genes identified through extensive data mapping were studied for their interaction with other target proteins involved in breast cancer progression. The molecular mechanisms by which these signature genes are involved in breast cancer metastasis were also studied through pathway analysis. The potential drug targets for these genes were also identified.

Results

From 50 DEGs, 20 genes were identified based on fold change and p-value and the data curation of these genes helped in shortlisting 8 potential gene signatures that can be used as potential candidates for breast cancer. Their network and pathway analysis clarified the role of these genes in breast cancer and their interaction with other signaling pathways involved in the progression of disease metastasis. The miRNA targets identified through miRDB predictor provided potential miRNA targets for these genes that can be involved in breast cancer progression. Several FDA approved drug targets were identified for the signature genes easing the therapeutic options for breast cancer treatment.

Conclusion

The study provides a more clarified role of signature genes, their interaction with other genes as well as signaling pathways. The miRNA prediction and the potential drugs identified will aid in assessing the role of these targets in breast cancer.

Physical activity and cancer risk. Actual knowledge and possible biological mechanisms

Background

Scientific evidence has shown that an increase in regular physical activity is associated with a decrease in the development of many types of cancer. Potential mechanisms that link physical activity to reduced cancer risk include a decrease in systemic inflammation, hyperinsulinemia, insulin-like growth factor (IGF-I), sex hormones, pro-inflammatory leptin and other obesity-related cytokines, and a significant increase in anti-inflammatory adiponectin levels. In addition, physical activity improves immune function and the composition and diversity of the gastrointestinal microbiota. Moderate physical activity is important for cancer protection, but the most significant changes in the inflammatory profile are conferred by physical activity performed at higher intensities. Thus, there is a need for further investigation into the type, intensity, and duration of physical activity for the prevention of some types of cancer and the development of effective recommendations.

Conclusions

There is a strong evidence that physical activity of moderate to vigorous intensity protects against colon and breast cancer, and probably against cancer at all other sites.

Physical Activity as an Imperative Support in Breast Cancer Management

Breast cancer (BC) is the most common malignancy and the second cause of cancer-related death among women. It is estimated that 9 in 10 cases of BC are due to non-genetic factors, and approximately 25% to 30% of total breast cancer cases should be preventable only by lifestyle interventions. In this context, physical activity represents an excellent and accessible approach not only for the prevention, but also for being a potential support in the management of breast cancer. The present review will collect the current knowledge of physical activity in the background of breast cancer, exploring its systemic and molecular effects, considering important variables in the training of these women and the evidence regarding the benefits of exercise on breast cancer survival and prognosis. We will also summarize the various effects of physical activity as a co-adjuvant therapy in women receiving different treatments to deal with its adverse effects. Finally, we will reveal the impact of physical activity in the enhancement of quality of life of these patients, to conclude the central role that exercise must occupy in breast cancer management, in an adequate context of a healthy lifestyle.

An exploration of the role of exercise in modulating breast cancer progression in vitro: a systematic review and meta-analysis

Breast cancer is the most prevalent cancer in women worldwide. In the United Kingdom, approximately 5% of all breast cancers are already metastatic at the time of diagnosis. An abundance of literature shows that exercise can have beneficial effects on the outcome and prognosis of breast cancer patients, yet the molecular mechanisms remain poorly understood. There are several in vitro models that aim to recapitulate the response of breast cancer to exercise in vivo; this systematic review and meta-analysis summarizes the existing literature. The following search terms were used to conduct a systematic literature search using a collection of databases (last search performed May 2020): "in vitro," "exercise," and "breast cancer." Only studies that investigated the effects of exercise on breast cancer in vitro were included. Standardized mean differences (SMD) were calculated to determine pooled effect sizes. This meta-analysis has successfully demonstrated that various identified exercise interventions on breast cancer cells in vitro significantly reduced breast cancer cell viability, proliferation, and tumorigenic potential (SMD = -1.76, P = 0.004, SMD = -2.85, P = 0.003, and SMD = -3.15, P = 0.0008, respectively). A clear direction of effect was found with exercise on breast cancer cell migration in vitro, however this effect was not significant (SMD = -0.62, P = 0.317). To our knowledge, this is the first meta-analysis and systematic review investigating and summarizing literature on exercise and breast cancer in vitro, highlighting models used and priority areas for future research focus.

Effects of major lifestyle factors on breast cancer risk: impact of weight, nutrition, physical activity, alcohol and tobacco

Breast cancer (BC) is the most commonly diagnosed cancer and second most common cause of cancer death in US women. Family history and genetics are well-known BC risk factors, but they only account for 15–20% of BC cases. Therefore, in addition to family history, healthcare providers must consider a woman’s modifiable and nonmodifiable personal risk factors that are associated with an increase in BC risk. The World Cancer Research Fund/American Institute for Cancer Research estimate that 30% of BC cases in the US are preventable. Lifestyle education is imperative given the magnitude of BC occurrence. Evidence supports prevention as an effective, long-term strategy for reducing risk. Healthcare providers are key stakeholders in empowering patients to adopt a healthy lifestyle for primary BC prevention. In this paper, we review the available evidence on modifiable BC risk including weight management, nutrition, physical activity, alcohol and tobacco use and provide strategies to counsel patients on lifestyle modifications.

Physical Activity and Breast Cancer Prevention: Possible Role of Immune Mediators

There is strong evidence that physical activity (PA) reduces risk, recurrence, and mortality from breast cancer. Emerging data suggest that PA induces changes in inflammatory and immune mediators that may contribute to beneficial effects on breast cancer outcomes. Thus, the goal of this review was to evaluate the evidence linking the protective benefit of PA to modulation of immune responses in breast cancer. A literature search was conducted to identify studies that evaluated the impact of PA on tumor and immune outcomes in breast cancer patients and in mammary tumor models. Nineteen studies investigated the effect of PA interventions on cancer immune outcomes using preclinical breast cancer models. Tumor growth was reduced in 11 studies, unchanged in three studies, and increased in one study. Spontaneous metastasis was reduced in two studies and survival was improved in four studies. Frequently assessed immune outcomes include splenic cell number and function, circulating inflammatory cytokines, and intratumoral immune cells and inflammatory markers. Circulating inflammatory cytokine responses were heterogeneous in preclinical models. Within the tumor microenvironment (TME), several studies documented a change in the infiltration of immune cells with an increase in effector cells and a reduction in immune suppressive cells. Twenty-three studies investigated the effect of PA interventions on immune outcomes in breast cancer patients. Thirteen studies used aerobic PA interventions and 10 studies used a combination of aerobic and resistance exercise interventions. Cycling and treadmill activities were the most commonly used PA modalities. Circulating immune cells and inflammatory cytokines were the most frequently assessed immune outcomes in the clinical studies. Among the 19 studies that evaluated a PA intervention during the post treatment period, 10 reported a reduction in the levels of at least one inflammatory cytokine. No inflammatory cytokines were quantified in the three studies that evaluated a PA intervention during treatment with chemotherapy. Immune outcomes within the tumor were assessed in only one study performing a PA intervention prior to surgery. Results from preclinical and clinical studies suggest that PA exerts heterogeneous effects on inflammatory cytokines, but may alter the gene expression profile and immune infiltrates in the tumor which may result in a reduction in immunosuppressive factors. However, additional studies are needed to better understand the effect of PA on immune outcomes in the TME.

Characterization of blood-derived exosomal proteins after exercise

Objective

To assess changes in plasma exosome levels and protein content in mice after long-term exercise.

Methods

We subjected 9-month-old adult C57BL/6J mice to daily treadmill running exercise for 4 weeks prior to the isolation of blood-derived exosomes. Exosomal proteins were identified using mass spectrometry.

Results

Extracellular bodies were successfully isolated from mouse blood. Protein levels were altered in blood-derived exosomes after chronic treadmill exercise. Levels of the secretagogue secretogranin 2 were markedly elevated in exercise-induced exosomes.

Conclusion

Our data suggest that levels of secretogranin 2 were increased in mouse exosomes following chronic treadmill exercise. We conclude that exercise increases exocrine secretion of secretogranin 2.

The oxytocin receptor signalling system and breast cancer: a critical review

Breast cancer is making up one-quarter of all new female cancer cases diagnosed worldwide. Breast cancer surgeries, radiation therapies, cytotoxic chemotherapies and targeted therapies have made significant progress and play a dominant role in breast cancer patient management. However, many challenges remain, including resistance to systemic therapies, tumour recurrence and metastasis. The cyclic neuropeptide oxytocin (OT) elicits a plethora of biological responses via the oxytocin receptor (OTR) in both the central and peripheral nervous system, including social bonding, stress, maternal behaviour, sexual activity, uterus contraction, milk ejection and cancer. As a typical member of the G protein-coupled receptor family, OTR represents also an intriguing target for cancer therapy. There is emerging evidence that OTR plays a role in breast cancer development and progression, and several breast cancer cell lines express OTR. However, despite supporting evidence that OT lowers breast cancer risks, its mechanistic role in breast cancer development and the related signalling pathways are not fully understood. Here, we review the current knowledge of the OT/OTR signalling system in healthy breast tissue as well as in breast cancer, and discuss OTR as a potential therapeutic target for breast cancer management.

Use of metformin and risk of breast and colorectal cancer

BACKGROUND

Diabetes has been associated with increased risk of cancer, including breast cancer and colorectal cancer. Metformin, an oral hypoglycemic drug, but not other anti-diabetic drugs, has been associated with reduced risk of breast and of colon cancers in some, but not in other, studies.

METHODS

Data from two large-scale, population-based, case-control studies of breast and colorectal cancers etiology, conducted in Northern Israel since 1998 were analyzed to evaluate the association between regular use (>3 times) of metformin prior to diagnosis and risk of developing cancer. The multivariate analyses for both cancer sites included age, family history of breast/colorectal cancer, history of diabetes, sports participation, fruits/vegetables consumption, aspirin and statins use, and for breast cancer, also included use of oral contraceptives and postmenopausal hormones and number of pregnancies. Use of metformin and diabetes status were determined based on valid electronic medical records of the participants.

RESULTS

Metformin use prior to diagnosis of cancer was associated with a decrease in risk of both breast cancer (OR = 0.821, 0.726-0.928, p = 0.002) and colorectal cancer (OR = 0.754, 0.623-0.912, p = 0.004). An inverse association was not identified with use of other anti-diabetic medications. Diabetes was found to be associated with risk of colorectal cancer (OR = 1.204, 1.014-1.431, p = 0.034) but not of breast cancer. No dose response by years of use of metformin was found.

CONCLUSION

These analyses of large population-based studies provide evidence of a strong inverse association of metformin with breast and, even more so, with colorectal cancer risk.

miR-623 suppresses cell proliferation, migration and invasion through direct inhibition of XRCC5 in breast cancer

Background/Aims: MicroRNAs (miRNAs) are short, non-coding RNA molecules that control gene expression trough negative translational regulation. MiR-623 is a tumor suppressor, and it’s function and mechanism in breast cancer has not been reported.

Results: Exogenous overexpression of miR-623 suppressed cell proliferation, migration and invasion, meanwhile, but promoted cell apoptosis. MiR-623 knockdown displayed opposite results. Overexpression of miR-623 resulted in the downregulation of CDK4/6 as well as the inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin signaling pathways. MiR-623 knockdown displayed opposite results. Results of the reporter assay revealed that the luciferase activity was decreased in XRCC5-wt cells, suggesting that miR-623 could directly combine with 3’ UTR of XRCC5. MiR-623 significantly suppressed XRCC5 expression, which is critical for miR-623-induced proliferation and migration block in breast cancer cells.

Conclusion: miR-623 suppressed cell proliferation, migration and invasion through downregulation of cyclin dependent kinases and inhibition of the phosphatidylinositol-3-kinase (PI3K)/Akt and Wnt/β-Catenin pathways by targeting XRCC5.

Methods: miR-623 was either overexpressed in breast cancer cell lines through exogenous transfection or knocked down by specific siRNA. Cell proliferation, migration and invasion were examined using CCK-8, colony formation and transwell assay. The direct target of miR-623 was verified using luciferase reporter gene assay.

Correlation between breast cancer and lifestyle within the Gulf Cooperation Council countries: A systematic review

BACKGROUND

In the six Gulf Cooperation Council countries (GCCCs), Bahrain, Saudi Arabia, Kuwait, Oman, Qatar and the United Arab Emirates, breast cancer (BC) is the greatest cause of cancer incidence and mortality. Obesity and physical inactivity are established risk factors for BC globally and appear to be more of a problem in high income countries like the GCCCs.

AIM

To determine whether obesity and physical inactivity are associated with BC incidence in the GCCCs using the United Kingdom as a comparator.

METHODS

This systematic review was carried out according to PRISMA guidelines. A cancer registry and a statistical data search was done to identify the BC incidence over the past two decades and the prevalence of obesity and physical inactivity in the GCCCs. Additionally, a systematic search of the databases, MEDLINE, Web of Science, and PubMed between 1999 and 2019 was performed to determine whether obesity and physical inactivity are risk factors for BC in the GCCCs. All papers were critically appraised according to their research methods and were assessed for quality and risk of bias.

RESULTS

BC was the top malignancy in each GCC country. Women tended to be diagnosed with BC at a younger age than women in the United Kingdom. The greatest 10-year increase in BC incidence was seen in Saudi Arabia (54.2%), approximately seven times the rate of increase seen in the United Kingdom (7.6%). The prevalence of obesity and physical inactivity was greater in all the GCCCs in comparison to the United Kingdom. A total of 155 full studies were reviewed of which 17 were included. Of those, eight looked at the prevalence of obesity and physical inactivity in the Gulf States and nine looked at these as risk factors for BC. Only one study found an association between BC and obesity (odds ratio = 2.29). No studies looked solely at the link between physical inactivity and BC.

CONCLUSION

The prevalence of obesity and physical inactivity was high within the GCCCs, but the majority of the included studies found no positive correlation between obesity or physical inactivity and BC. A high proportion of women in this study were pre-menopausal which could contribute to the negative findings.

Effects of an Evidence-based Exercise Intervention on Clinical Outcomes in Breast Cancer Survivors: A Randomized Controlled Trial

OBJECTIVES The number of breast cancer survivors throughout the world has increased. Breast cancer survivors need to know how to exercise to improve their clinical outcomes. The purpose of this study was to find the effects of an evidence-based combined exercise intervention on the fitness levels of breast cancer survivors.METHODS A total of 38 female breast cancer survivors were randomly assigned to an exercise group (n=19) or a control group who did usual care (n=19). Subjects in the exercise group participated eight weeks of moderate intensity aerobic exercise and bodyweight strength exercise three times per week. Weight, body mass index (BMI), cardiorespiratory fitness, handgrip strength, and flexibility were measured to assess the effects of the exercise intervention.RESULTS Women who completed the exercise intervention had decreased weight and BMI and increased cardiorespiratory fitness, handgrip strength, and flexibility.CONCLUSIONS Breast cancer survivors had improved health outcomes. A combined exercise intervention of moderate intensity three times per week for eight weeks can help breast cancer survivors improve their health. Participating in aerobic exercise and bodyweight strength exercise, which provide dynamic movements and use large muscle groups with no equipment, can help increase physical fitness levels of breast cancer survivors.

Exercise shapes redox signaling in cancer

In this paper of the special issue dedicated for the Olympics 2020, we put the light on an exciting facet of exercise-oncology, which may still be unknown to some audience. Accumulating convincing evidences show that exercise reduces cancer progression and recurrence mainly in colon and breast cancer patients. Interestingly, the positive effects of exercise on cancer outcomes were mainly observed when patients practiced vigorous exercise of 6 METs or more. At the molecular level, experimental studies highlighted that regular vigorous exercise could reduce tumor growth by driving changes in immune system, metabolism, hormones, systemic inflammation, angiogenesis and redox status. In the present review, we describe the main redox-sensitive mechanisms mediated by exercise. These redox mechanisms are of particular therapeutic interest as they may explain the emerging preclinical findings proving that the association of vigorous exercise with chemotherapy or radiotherapy improves the anti-cancer responses of both interventions. Clinical and preclinical studies converge to support the practice of exercise as an adjuvant therapy that improves cancer outcomes. The understanding of the underpinning molecular mechanisms of exercise in cancer can open new avenues to improve cancer care in patients.

The impact of alcohol consumption and physical activity on breast cancer: The role of breast cancer risk

High alcohol consumption and physical inactivity are known breast cancer risk factors. However, whether the association between these lifestyle factors and breast cancer is modified by a woman's additional breast cancer risk factors has never been studied. Therefore, a population‐based prospective cohort study of 57,654 Swedish women aged 40–74 years, including 957 breast cancer cases, was performed. Alcohol consumption and physical activity were measured with validated web‐based self‐report questionnaires. The Tyrer–Cuzick risk prediction model was used to determine a woman's 10‐year risk of developing breast cancer. Logistic regression models were used to explore whether the effect of alcohol consumption and physical activity on breast cancer was modified by additional breast cancer risk factors. Findings showed that increased alcohol consumption was associated with a higher breast cancer risk (OR = 1.26, 95% CI 1.01, 1.59). However, the association between lifestyle factors (alcohol consumption and physical activity) and breast cancer was generally the same for women at below average, average and above average risk of developing breast cancer. Therefore, additional breast cancer risk factors do not appear to modify the association between lifestyle (alcohol consumption and physical activity) and breast cancer. Considering the general health benefits, preventative lifestyle recommendations can be formulated about alcohol consumption and physical activity for women at all levels of breast cancer risk.

What's new?

Alcohol consumption and physical inactivity are known breast cancer risk factors but it is currently unclear whether all women would benefit equally from drinking less alcohol and being more physically active. The authors found no difference in association between these lifestyle factors and breast cancer in women with below average, average or above average risk of developing breast cancer. They conclude that general preventative lifestyle recommendations about alcohol intake and physical activity apply to all women regardless of their breast cancer risk.

Effects of Steady Low-Intensity Exercise on High-Fat Diet Stimulated Breast Cancer Progression Via the Alteration of Macrophage Polarization

Physical inactivity and high-fat diet, especially high saturated fat containing diet are established risk factors for breast cancer that are amenable to intervention. High-fat diet has been shown to induce tumor growth and metastasis by alteration of inflammation but steady exercise has anti-tumorigenic effects. However, the mechanisms underlying the effects of physical activity on high-fat diet stimulated breast cancer initiation and progression are currently unclear. In this study, we examined how the intensity of physical activity influences high fat diet-stimulated breast cancer latency and progression outcomes, and the possible mechanisms behind these effects. Five-week-old female Balb/c mice were fed either a control diet or a high-fat diet for 8 weeks, and then 4T1 mouse mammary tumor cells were inoculated into the mammary fat pads. Exercise training occurred before tumor cell injection, and tumor latency and tumor volume were measured. Mice with a high-fat diet and low-intensity exercise (HFLE) had a longer tumor latency period, slower tumor growth, and smaller tumor volume in the final tumor assessment compared with the control, high-fat diet control (HFDC), and high-fat diet with moderate-intensity exercise (HFME) groups. Steady low- and moderate-intensity exercise had no effect on cell proliferation but induced apoptosis by activating caspase-3 through the alteration of Bcl-2, Bcl-xL, and Bax expression. Furthermore, steady exercise reduced M2 macrophage polarization in breast tumor tissue, which has been linked to tumor growth. The myokine, myostatin, reduced M2 macrophage polarization through the inhibition of the JAK-STAT signaling pathway. These results suggest that steady low-intensity exercise could delay breast cancer initiation and growth and reduce tumor volume through the induction of tumor cell apoptosis and the suppression of M2 macrophage polarization.

Cardiovascular Disease Risk in Survivors of Breast Cancer

PURPOSE OF REVIEW

Early detection and improved treatment in breast cancer have resulted in an increased number of survivors. Cardiovascular disease now remains an important cause for morbidity and mortality in this population. There is a growing gap in the knowledge about the optimal long-term cardiovascular management of this population.

FINDINGS

Breast cancer and cardiovascular disease share a number of common risk factors. Different breast cancer treatment modalities, including anthracyclines, radiation, and hormonal therapy, can act in synergy with preexisting and/or new cardiovascular risk factors to result in significant cardiovascular disease. We summarize the recent evidence about cardiovascular effects of breast cancer therapy and recommendations for their diagnosis and management during the cancer treatment continuum into survivorship. We also present current research initiatives and how they inform clinical care.

Using a cultural dance program to increase sustainable physical activity for breast cancer survivors-A pilot study

BACKGROUND

Studies have shown that physical activity can reduce the risk of mortality for female breast cancer patients and improve quality of life, reduce weight, and alter circulating biomarker levels. We conducted a pilot trial to determine the feasibility of increasing physical activity through a cultural dance intervention to achieve similar benefits.

METHODS

Conducted a pilot trial implementing a cultural dance intervention to increase and sustain physical activity for breast cancer survivors, which consisted of a six-month group-based intervention of Hula Dance. Anthropometric measures, fasting blood draws, and self-reported questionnaires to assess physical activity, mood, and quality of life, were completed at baseline, at the end of the 6-month intervention (time point month-6), and at two additional post-intervention time points (month-12 and month-24) to assess sustainability.

RESULTS

A total of 11 women with a median age of 63 years were enrolled in the intervention trial. Eight of the 11 (73%) completed the trial to month-12 and demonstrated an overall significant increase in weekly moderate exercise. There were no significant changes in intra-individual body mass index (BMI). However, there was a sustained post-intervention reduction in waist circumference and significant changes in circulating biomarker levels. For the self-reported measures, there was a significant increase in vigor/activity (p < 0.001; Profile of Mood States-Short Form).

CONCLUSION

Our intervention pilot trial demonstrated that a cultural dance program could achieve a sustainable increase in physical activity for breast cancer survivors, with potential to improve quality of life, increase vigor, and decrease levels of circulating cytokines associated with obesity and inflammation.

An Intervention Tool to Increase Patient-Physician Discussion of Lifestyle Risk Factors for Breast Cancer

Background: Risk assessment and discussion of lifestyle in primary care are crucial elements of breast cancer prevention and risk reduction. Our objective was to evaluate the impact of a breast cancer risk assessment and education tool on patient-physician discussion of behaviors and breast cancer risk. Materials and Methods: We conducted a randomized controlled trial with an ethnically and linguistically diverse sample of women, ages 40-74, from two primary care practices. Intervention participants completed a tablet computer-based Breast Cancer Risk Assessment and Education (BreastCARE) intervention in the waiting room before a scheduled visit. Both patients and physicians received an individualized risk report to discuss during the visit. Control patients underwent usual care. Telephone surveys assessed patient-physician discussion of weight, exercise, and alcohol use 1 week following the visit. Results: Among the 1235 participants, 27.7% (161/580) intervention and 22.3% (146/655) usual-care patients were high risk for breast cancer. Adjusting for clustering by physician, the intervention increased discussions of regular exercise (odds ratios [OR] = 1.94, 1.50-2.51) and weight (OR = 1.56, 1.23-1.96). There was no effect of the intervention on discussion of alcohol. Women with some college education were more likely to discuss their weight than those with high school education or less (OR = 1.75, 1.03-2.96). Similarly, non-English speakers were more likely to discuss their weight compared with English speakers (OR = 2.33, 1.04-5.22). Conclusions: BreastCARE is a feasible risk assessment tool that can successfully promote discussions about modifiable breast cancer risk factors between patients and primary care physicians.

Airborne mammary carcinogens and breast cancer risk in the Sister Study

INTRODUCTION

Potentially carcinogenic hazardous air pollutants (air toxics) have been inconsistently associated with breast cancer. Whether metabolic factors modify these associations is unknown. We studied 29 non-metallic air toxics classified as mammary gland carcinogens in animal studies in relation to breast cancer risk.

METHODS

Participants included 49,718 women from the Sister Study. Census tract air toxic concentration estimates from the 2005 National Air Toxics Assessment were linked to enrollment residential addresses. Adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for individual air toxics were estimated using Cox regression. Body mass index (BMI) was considered a potential modifier. Relevant mixtures were identified using classification trees.

RESULTS

Over follow-up (average = 8.4 years), 2975 women were newly diagnosed with breast cancer (invasive or ductal carcinoma in situ). Several air toxics, including methylene chloride, polycyclic organic matter, propylene dichloride, and styrene, were associated with increased risk. Of these, methylene chloride was most consistently associated with risk across multiple analyses. It was associated with overall (HRquintile 4vs1 = 1.21 (95%CI = 1.07-1.38)) and estrogen receptor positive (ER+) invasive breast cancer (HRquintile 4vs1 = 1.28 (95%CI = 1.08-1.52)) in individual pollutant models, although no dose-response was observed. Associations were stronger among overweight/obese (vs. non-overweight/obese) women (p < 0.05) for six air toxics. The classification tree identified combinations of age, methylene chloride, BMI, and four other toxics (propylene dichloride, ethylene dibromide, ethylidene dichloride, styrene) related to overall breast cancer.

CONCLUSIONS

Some non-metallic air toxics, particularly methylene chloride, were associated with the hazard for overall and ER+ breast cancer. Overweight/obese women may be particularly susceptible to air toxics.

Anthropometric Obesity Indices, Body Fat Percentage, and Grip Strength in Young Adults with different Physical Activity Levels

The purposes of this study were to determine whether moderately physically active (MPA) and highly physically active (HPA) male (n = 96, age = 22.5 ± 1.7 years) and female (n = 85, age = 21.3 ± 1.6 years) young adults differed in their anthropometric obesity indices (AOIs), body fat percentage (BF%), and muscular strength, and also to examine the associations between physical activity level (PAL) and the abovementioned variables. Participants were measured for body height and weight, BF%, waist and hip circumferences, and maximal isometric grip strength. According to their PAL, estimated by the short version of the International Physical Activity Questionnaire, they were assigned to MPA and HPA subgroups. Regardless of gender, results indicated that participants in the MPA groups had significantly higher values of body weight, waist and hip circumference, BF%, and BMI than participants in the HPA groups. No significant differences were found between physical activity groups in terms of grip strength. The AOIs and BF% were found to be significantly and negatively correlated with the PAL in both genders. In conclusion, the findings of the study suggest that high habitual physical activity is associated with lower adiposity markers. However, the differences in the hand grip strength of the contrasting activity groups were negligible.

Deuterium Depleted Water Inhibits the Proliferation of Human MCF7 Breast Cancer Cell Lines by Inducing Cell Cycle Arrest

Recent studies have shown that the depletion of naturally occurring deuterium can result in tumor regression. The aim of the present study was to show the growth inhibitory effects of DDW discretely and in combination with 5-FU on MCF-7 breast cancer cells and to determine possible mechanisms underlying these changes. MCF7 cells were grown in RPMI medium with decreasing deuterium concentrations of DDW individually, 5-FU alone and both for 24, 48, and 72 h. Cell viability was determined with the MTT assay. The cell cycle and antioxidant enzymes status were measured using flow cytometry and quantitative luminescence methods, respectively. Our results showed that treatment with DDW especially in 30-100 ppm concentrations imposed the highest cell growth inhibitory effect. The cell cycle analysis revealed that DDW caused the cell cycle arrest in the G1/S transition, reduced the number of the cells in the S phase and significantly increased the population of cells in the G1 phase in MCF-7 cells. The activities of superoxide dismutase (SOD) and catalase (CAT) enzymes also increased in the same low concentrations of DDW. In conclusion, DDW can open new strategic approach in breast cancer therapy. Highlights DDW cause lethality in cancer cells. DDW augmented 5-FU inhibitory effects on breast cancer cell lines. Cell inhibitory results lead to the discovery of synergic effects of DDW-drug combinations Synergistic anti cancer effects of DDW with 5-FU is enhanced by decreasing deuterium content of the DDW. DDW exerts effects on the cell cycle, changes in cell configuration and induces antioxidant enzymes in vitro. DDW can be considered as an adjuvant to conventional anticancer agents in future trials.

Cell Signaling Pathways in Mammary Carcinoma Induced in Rats with Low versus High Inherent Aerobic Capacity

An inverse association exists between physical activity and breast cancer incidence and outcomes. An objective indicator of an individual’s recent physical activity exposure is aerobic capacity. We took advantage of the fact that there is an inherited as well as inducible component of aerobic capacity to show that experimentally induced mammary cancer is inversely related to inherent aerobic capacity (IAC). The objective of this study was to determine whether cell signaling pathways involved in the development of mammary cancer differed in rats with low inherent aerobic capacity (LIAC, n = 55) versus high inherent aerobic capacity (HIAC, n = 57). Cancer burden was 0.21 ± 0.16 g/rat in HIAC versus 1.14 ± 0.45 in LIAC, p < 0.001. Based on protein expression, cancer in LIAC animals was associated with upregulated glucose utilization, and protein and fatty acid synthesis. Signaling in cancers from HIAC rats was associated with energy sensing, fatty acid oxidation and cell cycle arrest. These findings support the thesis that pro-glycolytic, metabolic inflexibility in LIAC favors not only insulin resistance and obesity but also tumor development and growth. This provides an unappreciated framework for understanding how obesity and low aerobic fitness, hallmarks of physical inactivity, are associated with higher cancer risk and poorer prognosis.

Physical activity and survival following breast cancer

INTRODUCTION

Physical activity (PA) leads to improved survival in women following the diagnosis of breast cancer, but it is less clear whether PA has equally positive effects regardless of age at diagnosis. The purpose of our study was to evaluate the association between post-diagnosis PA and survival in women aged below or over 55 years at diagnosis.

METHODS

From a prospective population-based cohort of Swedish women, we included 847 women, aged 34-84 years, who were diagnosed with breast cancer from 1992 to 2012. A PA score was calculated based on three different questions regarding self-reported PA. Cox proportional hazard model was used to estimate the association between PA and mortality.

RESULTS

A significant association between PA score and all-cause mortality was observed, in a dose-response manner (p_trend  = 0.01). The mortality was clearly lower in the most active compared to the least active group (hazard ratio 0.29, 95% confidence intervals 0.09-0.90). A subgroup analysis showed that the improved survival was only seen in women over 55 years of age at diagnosis.

CONCLUSION

Physical activity, which is a modifiable lifestyle factor, should be encouraged after breast cancer diagnosis, especially in women with post-menopausal breast cancer.

Adult Physical Activity and Breast Cancer Risk in Women with a Family History of Breast Cancer

BACKGROUND

Recreational physical activity has been consistently associated with reduced breast cancer risk. Less is known about how family history of breast cancer affects the association and whether it varies by menopausal status.

METHODS

The Sister Study is a cohort of 50,884 women who had a sister with breast cancer but no prior breast cancer themselves at enrollment. Women reported all recreational sport/exercise activities they participated in over the past 12 months. Hours/week and MET-hours/week of physical activity were considered in association with breast cancer risk. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated with Cox regression. Extent of family history, examined as a modifier, was characterized by a Bayesian score incorporating characteristics of the family structure.

RESULTS

During follow-up (average 8.4 years), 3,023 cases were diagnosed. Higher hours/week (HR_≥7vs<1 = 0.77; 95% CI, 0.66-0.90) and MET-hours/week (HR_quartile4vs1 = 0.75; 95% CI, 0.67-0.85) of physical activity were associated with reduced postmenopausal breast cancer risk. Hours/week and MET-hours/week were associated with suggestively increased premenopausal breast cancer risk (MET-hours/week HR_quartile4vs1 = 1.25; 95% CI, 0.98-1.60). Associations did not vary with extent of family history. However, the increased risk in premenopausal women may be limited to those with stronger family history.

CONCLUSIONS

In women with a family history of breast cancer, physical activity was associated with reduced postmenopausal, but not premenopausal, breast cancer risk and was not modified by extent of family history.

IMPACT

This was the first study to examine the association between physical activity and breast cancer risk in a large population with a family history of breast cancer.

Regular physical activity and mammographic density: a cohort study

Purpose

Physical activity is a modifiable lifestyle risk factor in prevention of breast cancer. Mammographic density (MD) is a strong risk factor for breast cancer. We investigate the association of regular physical activity with MD.

Methods

For 5,703 women who participated in the Danish Diet, Cancer and Health cohort (1993–1997) and attended mammographic screening in Copenhagen (1993–2001), MD was assessed at the first screening after cohort entry. MD was defined as a binary measure equivalent to Breast Imaging Report and Data System (BI-RADS) to either mixed/dense or fatty. Participation and duration in physical activities (hours/week) and confounders were assessed by questionnaire at cohort baseline. Logistic regression was used to estimate associations [odds ratios (OR), 95% confidence intervals (CI)] between physical activities and MD.

Results

56.3% of women had mixed/dense MD and 47.6% participated in sports. We found a significant positive association between participation in sports (OR 1.15; 95% CI 1.03–1.28) and do-it-yourself work (1.17; 1.05–1.31) and odds of having mixed/dense MD, which attenuated (1.08; 0.96–1.22 and 1.11; 0.98–1.25, respectively) in a fully adjusted model. No associations were found for time spent on physical activities or total metabolic equivalent of task scores with MD, in fully adjusted models. There was no effect modification of association between any physical activities and MD by obesity (BMI ≥ 30 kg/m²) and menopause status.

Conclusions

Physical activity is not a determinant of MD.

Electronic supplementary material

The online version of this article (10.1007/s10552-018-1075-3) contains supplementary material, which is available to authorized users.

Modifiable Lifestyle Factors: Opportunities for (Hereditary) Breast Cancer Prevention - a Narrative Review

Increasing rates of obesity, lack of physical activity, sedentary behavior, and frequent alcohol consumption are major lifestyle-related risk factors for breast cancer. In fact, it has been estimated that about one-third of breast cancer cases are attributable to factors women can change. Most research has focused on examining the impact of one single exposure on breast cancer risk while adjusting for other risk modifiers. Capitalizing on big data, major efforts have been made to evaluate the combined impact of well-established lifestyle factors on overall breast cancer risk. At the individual level, data indicate that even simple behavior modifications could have a considerable impact on breast cancer prevention. Moreover, there is emerging new evidence that adopting a healthy lifestyle may be particularly relevant for women with hereditary susceptibility to breast cancer. On the absolute risk scale, studies suggest that the presence of certain risk factors, such as excessive body weight, had a substantially higher impact on breast cancer risk if women had a hereditary predisposition to cancer. The existing body of knowledge gives the medical professionals guidance as to which factors to focus on when counseling patients. However, well-designed randomized controlled trials utilizing objective methods are crucial to providing concrete recommendations.

Cardiovascular Disease and Breast Cancer: Where These Entities Intersect: A Scientific Statement From the American Heart Association

Cardiovascular disease (CVD) remains the leading cause of mortality in women, yet many people perceive breast cancer to be the number one threat to women's health. CVD and breast cancer have several overlapping risk factors, such as obesity and smoking. Additionally, current breast cancer treatments can have a negative impact on cardiovascular health (eg, left ventricular dysfunction, accelerated CVD), and for women with pre-existing CVD, this might influence cancer treatment decisions by both the patient and the provider. Improvements in early detection and treatment of breast cancer have led to an increasing number of breast cancer survivors who are at risk of long-term cardiac complications from cancer treatments. For older women, CVD poses a greater mortality threat than breast cancer itself. This is the first scientific statement from the American Heart Association on CVD and breast cancer. This document will provide a comprehensive overview of the prevalence of these diseases, shared risk factors, the cardiotoxic effects of therapy, and the prevention and treatment of CVD in breast cancer patients.

Efficacy of Complementary Therapies in the Quality of Life of Breast Cancer Survivors

Breast cancer (BC) is the most common cancer diagnosed in women and the second most common cancer overall, ranking as the fifth cause of death from cancer. The chronicity of the disease produces long-term physiological and psychological manifestations, which adversely affect the quality of life of the individual. The primary treatment while managing cancer presents with various debilitating side effects. With the recent advances in treatment techniques that have improved the survival rate, patients suffer from continuing posttreatment complications. Patients seem to cope well with the stress of treatment of BC and sustain a normal life; however, the deterioration in physical well-being makes the patient functionally inefficient. Exercise has been proven to be an effective, safe, and feasible tool in combating the adverse effects of treatment, prevents complications and decreases the risk of BC-specific mortality. This review briefly presents an overview of the burden of the disease and its management strategies. Owing to the heterogeneity of the population and the multitude of therapies they receive, the response of each patient to treatment is different and so is the magnitude of adverse effects. The review discusses the late sequelae following treatment and evidence supporting the role of physical activity in their management. In conclusion, there is a need for personalized physical activity plans to be developed to suit the individual and their circumstances.

Relationship between physical activity, disability, and physical fitness profile in sedentary Latina breast cancer survivors

OBJECTIVE

To report baseline data from a physical activity (PA) intervention for Latina breast cancer survivors, and assess the relationship between PA, fitness, and disability.

METHODS

Eighty-nine Latina breast cancer survivors from San Juan, PR and Houston, TX (age: 55.4 ± 9.9 years; BMI: 29.87 ± 5.62 kg/m²; ≥ 3 months post-treatment) participated in this study. At baseline participants completed fitness testing (six-minute walk test [6MWT], 30-second sit-stand; grip strength, lower and upper extremity and low back strength, shoulder range of motion, balance testing), and assessment of physical activity (PA) and disability. PA was assessed using the International Physical Activity Questionnaire (IPAQ). A subsample (n = 27) received an accelerometer to compare objective versus self-reported PA.

RESULTS

Participants exhibited low PA (M = 76.5 MET·minutes/week; SD = 183.4), poor fitness (6MWT M = 436.4 meters, SD = 99.1; 30s sit-stand, M = 11.6 stands, SD = 3.1), and no detectable disability. In an adjusted model lower extremity fitness was associated with PA, with a one repetition increase in sit-to-stand associated with 49 additional minutes of self-reported PA plus walking per week. The correlation between IPAQ moderate-vigorous PA and accelerometer was 0.38 (p = 0.047).

CONCLUSION

Latina breast cancer survivors have low physical activity and fitness levels that increase their risk of disability, cardiometabolic comorbidities, and potential cancer recurrence.

A Systematic Review of the Effect of Lifestyle Interventions on Adipose Tissue Gene Expression: Implications for Carcinogenesis

OBJECTIVE

The mechanisms driving the associations between body weight and physical activity levels and multiple types of cancer are not yet well understood. The purpose of this review was to examine the effects of lifestyle interventions on proposed biomarkers of lifestyle and cancer risk at the level of adipose tissue in humans.

METHODS

Embase, MEDLINE, and CINAHL were searched by using keywords relating to exercise or diet interventions, adipose tissue biology, and outcomes of interest. Eligible studies included randomized clinical trials of exercise and/or dietary interventions in humans compared with control or other interventions, reporting the collection of subcutaneous abdominal adipose tissue.

RESULTS

Nineteen studies met criteria for inclusion. Eight studies modified dietary intake, five altered exercise levels, and six studies used a combination of both. Change in subcutaneous adipose tissue gene expression was most commonly observed with dietary weight loss, with a pattern of decrease in leptin, tumor necrosis factor alpha, and interleukin 6, along with an increase in adiponectin. There was limited change with exercise-only interventions or study arms.

CONCLUSIONS

Interventions leading to weight loss result in an altered gene expression of adipokines and inflammatory markers in subcutaneous adipose tissue, while less change in gene expression was noted with exercise alone.

Change in Physical Activity During a Weight Management Intervention for Breast Cancer Survivors: Association with Weight Outcomes

OBJECTIVE

This study examined the effects of a group phone-based weight management intervention on change in physical activity as measured via accelerometer and self-report in rural breast cancer survivors. The study also evaluated the role of physical activity on clinically meaningful cut points for weight loss (baseline to 6 months) and weight loss maintenance (6 to 18 months).

METHODS

Participants were breast cancer survivors in a weight management intervention who provided valid weight and accelerometer data (N = 142). Participants were categorized into four groups based on weight loss ≥10% and weight regain ≥5% at 18 months.

RESULTS

Accelerometer-measured moderate-to-vigorous physical activity (MVPA) significantly increased from baseline to 6 months (+46.9 minutes). MVPA declined during maintenance but remained significantly greater than baseline. Self-reported MVPA followed a similar pattern as accelerometer MVPA, but estimates were significantly higher. Participants in the high loss, low regain group had significantly higher MVPA at all points.

CONCLUSIONS

A distance-based weight management intervention for survivors improved physical activity outcomes over 18 months. Self-reported physical activity was substantially higher than accelerometer measured. Findings highlight the importance of device-based measurement for characterizing the magnitude of physical activity change as well as the role of physical activity in weight management outcomes.

Black rice-derived anthocyanins inhibit HER-2-positive breast cancer epithelial-mesenchymal transition-mediated metastasis in vitro by suppressing FAK signaling

This study aimed to investigate the role of focal adhesion kinase (FAK) signaling in the inhibitory effects of black rice anthocyanins (BRACs) on human epidermal growth factor receptor-2 (HER-2)-positive human breast cancer cell metastasis, using the MCF-10A, MCF-7 and MDA-MB-453 cells. BRACs exerted an anti-metastatic effect on the HER-2-positive breast cancer cells. The effects of BRACs on the proliferation of the MDA-MB-453 cells were examined by cell counting kit-8 assay. A wound-healing assay was used to examine the effects of BRACs on the migration of the breast cancer cells. BRACs interrupted migration and invasion. BRACs decreased the migration distance of the HER-2-positive human breast cancer cells, MDA-MB-453, by 37% compared with the cells in the untreated group. They also reduced the number of invading MDA-MB-453 cells by 68%. In addition, BRACs exerted an inhibitory effect on epithelial-mesenchymal transition. Western blot analysis revealed that BRACs decreased the phosphorylation of FAK, cSrc and p130^Cas. The FAK inhibitor, Y15, was also used to further evaluate the role of FAK signaling in the anti-metastatic effects of BRACs on MDA-MB-453 cells. The results of western blot analysis revealed that BRACs increased the expression of the epithelial marker, E-cadherin, and decreased the expression of the mesenchymal markers, fibronectin and vimentin, in the MDA-MB-453 cells. In addition, BRACs decreased the interaction between HER-2 and FAK, FAK and cSrc, cSrc and p130^Cas, and between FAK and p130^Cas. These results suggest that BRACs suppress the metastasis of HER-2-positive breast cancer in vitro, and that the cSrc/FAK/p130^Cas pathway plays a vital role in this inhibitory effect.

Inherent aerobic capacity-dependent differences in breast carcinogenesis

Although regular physical activity is associated with improvement in aerobic capacity and lower breast cancer risk, there are heritable sets of traits that affect improvement in aerobic capacity in response to physical activity. Although aerobic capacity segregates risk for a number of chronic diseases, the effect of the heritable component on cancer risk has not been evaluated. Therefore, we investigated breast carcinogenesis in rodent models of heritable fitness in the absence of induced physical activity. Female offspring of N:NIH rats selectively bred for low (LIAC) or high (HIAC) inherent aerobic capacity were injected intraperitoneally with 1-methyl-1-nitrosurea (70 mg/kg body wt). At study termination 33 weeks post-carcinogen, cancer incidence (14.0 versus 47.3%; P < 0.001) and multiplicity (0.18 versus 0.85 cancers per rat; P < 0.0001) were significantly decreased in HIAC versus LIAC rats, respectively. HIAC had smaller visceral and subcutaneous body fat depots than LIAC and activity of two proteins that regulated the mammalian target of rapamycin, protein kinase B (Akt), and adenosine monophosphate-activated protein kinase were suppressed and activated, respectively, in HIAC. Although many factors distinguish between HIAC and LIAC, it appears that the protective effect of HIAC against breast carcinogenesis is mediated, at least in part, via alterations in core metabolic signaling pathways deregulated in the majority of human breast cancers.

Role of Inactivity in Chronic Diseases: Evolutionary Insight and Pathophysiological Mechanisms

This review proposes that physical inactivity could be considered a behavior selected by evolution for resting, and also selected to be reinforcing in life-threatening situations in which exercise would be dangerous. Underlying the notion are human twin studies and animal selective breeding studies, both of which provide indirect evidence for the existence of genes for physical inactivity. Approximately 86% of the 325 million in the United States (U.S.) population achieve less than the U.S. Government and World Health Organization guidelines for daily physical activity for health. Although underappreciated, physical inactivity is an actual contributing cause to at least 35 unhealthy conditions, including the majority of the 10 leading causes of death in the U.S. First, we introduce nine physical inactivity-related themes. Next, characteristics and models of physical inactivity are presented. Following next are individual examples of phenotypes, organ systems, and diseases that are impacted by physical inactivity, including behavior, central nervous system, cardiorespiratory fitness, metabolism, adipose tissue, skeletal muscle, bone, immunity, digestion, and cancer. Importantly, physical inactivity, itself, often plays an independent role as a direct cause of speeding the losses of cardiovascular and strength fitness, shortening of healthspan, and lowering of the age for the onset of the first chronic disease, which in turn decreases quality of life, increases health care costs, and accelerates mortality risk.