Smoking and physical inactivity increase cancer prevalence in BRCA-1 and BRCA-2 mutation carriers: results from a retrospective observational analysis

Prevention and Co-Management of Breast Cancer-Related Osteoporosis Using Resveratrol

Breast cancer (BC) is currently one of the most common cancers in women worldwide with a rising tendency. Epigenetics, generally inherited variations in gene expression that occur independently of changes in DNA sequence, and their disruption could be one of the main causes of BC due to inflammatory processes often associated with different lifestyle habits. In particular, hormone therapies are often indicated for hormone-positive BC, which accounts for more than 50-80% of all BC subtypes. Although the cure rate in the early stage is more than 70%, serious negative side effects such as secondary osteoporosis (OP) due to induced estrogen deficiency and chemotherapy are increasingly reported. Approaches to the management of secondary OP in BC patients comprise adjunctive therapy with bisphosphonates, non-steroidal anti-inflammatory drugs (NSAIDs), and cortisone, which partially reduce bone resorption and musculoskeletal pain but which are not capable of stimulating the necessary intrinsic bone regeneration. Therefore, there is a great therapeutic need for novel multitarget treatment strategies for BC which hold back the risk of secondary OP. In this review, resveratrol, a multitargeting polyphenol that has been discussed as a phytoestrogen with anti-inflammatory and anti-tumor effects at the epigenetic level, is presented as a potential adjunct to both support BC therapy and prevent osteoporotic risks by positively promoting intrinsic regeneration. In this context, resveratrol is also known for its unique role as an epigenetic modifier in the regulation of essential signaling processes-both due to its catabolic effect on BC and its anabolic effect on bone tissue.

Associations of height, body mass index, and weight gain with breast cancer risk in carriers of a pathogenic variant in BRCA1 or BRCA2: the BRCA1 and BRCA2 Cohort Consortium

INTRODUCTION

Height, body mass index (BMI), and weight gain are associated with breast cancer risk in the general population. It is unclear whether these associations also exist for carriers of pathogenic variants in the BRCA1 or BRCA2 genes.

PATIENTS AND METHODS

An international pooled cohort of 8091 BRCA1/2 variant carriers was used for retrospective and prospective analyses separately for premenopausal and postmenopausal women. Cox regression was used to estimate breast cancer risk associations with height, BMI, and weight change.

RESULTS

In the retrospective analysis, taller height was associated with risk of premenopausal breast cancer for BRCA2 variant carriers (HR 1.20 per 10 cm increase, 95% CI 1.04-1.38). Higher young-adult BMI was associated with lower premenopausal breast cancer risk for both BRCA1 (HR 0.75 per 5 kg/m2, 95% CI 0.66-0.84) and BRCA2 (HR 0.76, 95% CI 0.65-0.89) variant carriers in the retrospective analysis, with consistent, though not statistically significant, findings from the prospective analysis. In the prospective analysis, higher BMI and adult weight gain were associated with higher postmenopausal breast cancer risk for BRCA1 carriers (HR 1.20 per 5 kg/m2, 95% CI 1.02-1.42; and HR 1.10 per 5 kg weight gain, 95% CI 1.01-1.19, respectively).

CONCLUSION

Anthropometric measures are associated with breast cancer risk for BRCA1 and BRCA2 variant carriers, with relative risk estimates that are generally consistent with those for women from the general population.

Modifiable risk factors in women at high risk of breast cancer: a systematic review

BACKGROUND

Modifiable risk factors (alcohol, smoking, obesity, hormone use, and physical activity) affect a woman's breast cancer (BC) risk. Whether these factors affect BC risk in women with inherited risk (family history, BRCA1/2 mutations, or familial cancer syndrome) remains unclear.

METHODS

This review included studies on modifiable risk factors for BC in women with inherited risk. Pre-determined eligibility criteria were used and relevant data were extracted.

RESULTS

The literature search resulted in 93 eligible studies. For women with family history, most studies indicated that modifiable risk factors had no association with BC and some indicated decreased (physical activity) or increased risk (hormonal contraception (HC)/menopausal hormone therapy (MHT), smoking, alcohol). For women with BRCA mutations, most studies reported no association between modifiable risk factors and BC; however, some observed increased (smoking, MHT/HC, body mass index (BMI)/weight) and decreased risk (alcohol, smoking, MHT/HC, BMI/weight, physical activity). However, measurements varied widely among studies, sample sizes were often small, and a limited number of studies existed.

CONCLUSIONS

An increasing number of women will recognize their underlying inherited BC risk and seek to modify that risk. Due to heterogeneity and limited power of existing studies, further studies are needed to better understand how modifiable risk factors influence BC risk in women with inherited risk.

Information needs on nutrition in link to cancer prevention among cancer patients, high-risk individuals and general population - A national cross-sectional study

BACKGROUND & AIMS

Nutrition is one of the fundamentals of cancer prevention. Knowing what are the patients' needs and beliefs in terms of "nutrition and cancer" information helps tailor future nutritional interventions. The aim of this study was to evaluate specific information needs about "nutrition in relation to cancer prevention", including primary and tertiary prevention, among cancer patients, cancer-free individuals, and genetic high cancer risk individuals.

METHODS

This online survey was shared within two large National cancer social networks and proposed to all attendees and carers of a comprehensive cancer center.

RESULTS

2887 individuals answered the survey (of whom 33% were cancer patients, 13% high-risk individuals and 55% participants of the general population). More than 80% of participants were women, had at least a high school degree. Median body mass index was 23.2 kg/m². Eleven percent (n = 321) were following a diet, mostly low carbohydrate and weight-loss diets. Around 70% of all categories felt they lacked information on nutrition and cancer interplays. Only 12% of cancer patients (n = 108) considered they had received enough information on nutrition during their care pathway. A majority of participants agreed that food can modify cancer risk (93%, n = 2526) and 66% (n = 1781) considered that nutrition should be personalized according to the risk of cancer. Only twenty-nine percent (n = 792) believed that eating 5 fruits and vegetables a day was enough to avoid cancer, but 64% (n = 1720) thought that dietary supplements could help obtain a better health. All proposed nutrition topics were considered important by the participants.

CONCLUSIONS

Although cancer patients and cancer-free respondents, whether at high risk of cancer or not, share a common broad interest on the interplay between nutrition and cancer and seek after more information on this topic, some false beliefs are observed. Healthcare providers could successfully propose more evidence-based information to these populations.

The Key Role of Mitochondrial Function in Health and Disease

The role of mitochondrial function in health and disease has become increasingly recognized, particularly in the last two decades. Mitochondrial dysfunction as well as disruptions of cellular bioenergetics have been shown to be ubiquitous in some of the most prevalent diseases in our society, such as type 2 diabetes, cardiovascular disease, metabolic syndrome, cancer, and Alzheimer's disease. However, the etiology and pathogenesis of mitochondrial dysfunction in multiple diseases have yet to be elucidated, making it one of the most significant medical challenges in our history. However, the rapid advances in our knowledge of cellular metabolism coupled with the novel understanding at the molecular and genetic levels show tremendous promise to one day elucidate the mysteries of this ancient organelle in order to treat it therapeutically when needed. Mitochondrial DNA mutations, infections, aging, and a lack of physical activity have been identified to be major players in mitochondrial dysfunction in multiple diseases. This review examines the complexities of mitochondrial function, whose ancient incorporation into eukaryotic cells for energy purposes was key for the survival and creation of new species. Among these complexities, the tightly intertwined bioenergetics derived from the combustion of alimentary substrates and oxygen are necessary for cellular homeostasis, including the production of reactive oxygen species. This review discusses different etiological mechanisms by which mitochondria could become dysregulated, determining the fate of multiple tissues and organs and being a protagonist in the pathogenesis of many non-communicable diseases. Finally, physical activity is a canonical evolutionary characteristic of humans that remains embedded in our genes. The normalization of a lack of physical activity in our modern society has led to the perception that exercise is an "intervention". However, physical activity remains the modus vivendi engrained in our genes and being sedentary has been the real intervention and collateral effect of modern societies. It is well known that a lack of physical activity leads to mitochondrial dysfunction and, hence, it probably becomes a major etiological factor of many non-communicable diseases affecting modern societies. Since physical activity remains the only stimulus we know that can improve and maintain mitochondrial function, a significant emphasis on exercise promotion should be imperative in order to prevent multiple diseases. Finally, in populations with chronic diseases where mitochondrial dysfunction is involved, an individualized exercise prescription should be crucial for the "metabolic rehabilitation" of many patients. From lessons learned from elite athletes (the perfect human machines), it is possible to translate and apply multiple concepts to the betterment of populations with chronic diseases.

How Does Dietary Intake Relate to Dispositional Optimism and Health-Related Quality of Life in Germline BRCA1/2 Mutation Carriers?

Background: The Mediterranean diet (MD) is an anti-inflammatory diet linked to improved health-related quality of life (HRQoL). Germline (g)BRCA1/2 mutation carriers have an increased risk of developing breast cancer and are often exposed to severe cancer treatments, thus the improvement of HRQoL is important. Little is known about the associations between dietary intake and HRQoL in this population. Methods: We included 312 gBRCA1/2 mutation carriers from an ongoing prospective randomized controlled lifestyle intervention trial. Baseline data from the EPIC food frequency questionnaire was used to calculate the dietary inflammatory index (DII), and adherence to MD was captured by the 14-item PREDIMED questionnaire. HRQoL was measured by the EORTC QLQ-C30 and LOT-R questionnaires. The presence of metabolic syndrome (MetS) was determined using anthropometric measurements, blood samples and vital parameters. Linear and logistic regression models were performed to assess the possible impact of diet and metabolic syndrome on HRQoL. Results: Women with a prior history of cancer (59.6%) reported lower DIIs than women without it (p = 0.011). A greater adherence to MD was associated with lower DII scores (p < 0.001) and reduced odds for metabolic syndrome (MetS) (p = 0.024). Women with a more optimistic outlook on life reported greater adherence to MD (p < 0.001), whereas a more pessimistic outlook on life increased the odds for MetS (OR = 1.15; p = 0.023). Conclusions: This is the first study in gBRCA1/2 mutation carriers that has linked MD, DII, and MetS to HRQoL. The long-term clinical implications of these findings are yet to be determined.

Physical Activity in Young BRCA Carriers and Reduced Risk of Breast Cancer

INTRODUCTION

A systematic literature review was conducted to determine whether physical activity levels during adolescent and young adult years were associated with a reduced lifetime risk of breast cancer among carriers of deleterious mutations in BRCA1 and BRCA2 genes.

METHODS

Ovid/MEDLINE, Embase, CENTRAL, WOS, and CINAHL were searched for articles including information about adolescent and young adult physical activity and breast cancer incidence among women carrying deleterious BRCA1 and BRCA2 gene mutations (search was initiated in October 2019; last update and full analyses were in March 2021). Independent reviewers screened articles at the title/abstract and full-text levels, resolving differences by consensus with lead authors. The NIH Quality Assessment Tools were used to assess sources of bias.

RESULTS

A total of 1,957 unique articles were identified; 5 met inclusion criteria. Samples size ranged from 68 to 1,185. All studies relied on self-reported adolescent and young adult physical activity. One study measured sports involvement; the others measured recreational activity. One large study was null, whereas 4 others showed a reduction in breast cancer incidence later in life with higher adolescent and young adult physical activity (p≤0.05). However, the protection was limited to premenopausal breast cancer in 1 of the studies (OR=0.62; 95% CI=0.40, 0.96; p-trend=0.01). In addition, adolescent and young adult physical activity was associated with older age at breast cancer diagnosis in 1 study (p=0.03).

CONCLUSIONS

A limited number of studies suggest that adolescent and young adult physical activity may reduce or delay the risk of breast cancer incidence among carriers of deleterious mutations in BRCA1 and BRCA2 genes.

Management Strategies of Breast Cancer Patients with BRCA1 and BRCA2 Pathogenic Germline Variants

Most of breast cancer cases are sporadic; however, 15–20% are associated with family history, and some are inherited. Among those, deleterious mutations in BRCA1 and BRCA2 tumor suppressor genes are the most commonly encountered pathogenic germline variants (PGVs). Given the availability and affordability of multi-gene panel sequencing technologies, testing for PGVs is commonly practiced. With our enhanced understanding of cancer genetics and specific molecular alterations, the better acceptance of risk-directed screening and prevention, and the recent introduction of novel targeted therapies, management of BRCA-positive breast cancers is taking a new direction, focusing more on risk-reducing interventions, including mastectomy and salpingo-oophorectomy, and incorporating special treatment regimens, including platinum-based chemotherapy, and the recently-introduced PARP (poly (ADP)-ribose polymerase) inhibitors. Given the recent advances in reproductive technology and molecular medicine, younger women with PGVs may have the option of embryo selection through preimplantation genetic testing and diagnosis, thus preventing the potential transmission of the implicated genes to the next generations. In this review, we cover the clinical implications of identifying a pathogenic germline mutation in BRCA1 and BRCA2 genes in breast cancer patients, and their relatives, across the continuum of care – from cancer prevention and early detection, through active treatment and up to survivorship issues.

Influence of Breast Reduction Surgery on Long-Term Breast Cancer Risk in Austria

INTRODUCTION

Breast reduction surgery is one of the most frequently performed surgeries amongst plastic and reconstructive surgeons worldwide. Previous studies have shown decreased risk of breast cancer development in women undergoing breast reduction surgery of up to 28%. We aimed to evaluate the relative risk of breast cancer development in our patients after breast reduction surgery in relation to the general female population of Austria.

METHODS

A total of 637 women underwent breast reduction surgery between 2003 and 2017 at our department. From those women, 513 patients completed a follow-up assessment of breast cancer development and were included into the study sample. The age-specific incidence rate data of the general female population of Austria served as the control group and basis for the calculation of the standardized incidence ratio (SIR) and Poisson test.

RESULTS

Relative to 5.66 expected cases of breast cancer, our cohort showed 1 subject with breast cancer after breast reduction surgery (SIR = 0.1765). An exact Poisson test was carried out to determine the level of significance of the difference between the incidence rate observed in the sample compared to the expected rate based on the age-specific incidence rates of the general population (p = 0.023, α = 0.05).

DISCUSSION

Our study underlines the strong evidence of previous studies for significant breast cancer reduction in patients after reductive mammoplasty. In comparison to the general female population of Austria, our cohort showed a reduction in breast cancer incidence of about 82%. The authors believe that different techniques in reduction mammoplasty have different levels of safety regarding the prevention and risk reduction for breast cancer. Further investigation must be conducted to evaluate the reduction of breast cancer risk with different surgical techniques.

Predictors of cardiopulmonary fitness in cancer-affected and -unaffected women with a pathogenic germline variant in the genes BRCA1/2 (LIBRE-1)

Physical activity (PA) helps prevention and aftercare of sporadic breast cancer (BC), cardiopulmonary fitness (CPF) being an age-independent predictor of tumor-specific mortality. Therefore, we wanted to identify predictors of CPF (represented by peak oxygen uptake: VO_2peak) in BRCA1/2 mutation carriers whose risk of developing BC is high. We used cross-sectional data from 68 BRCA1/2 germline mutation carrying women participating in the randomized, prospective, controlled clinical study LIBRE-1. Assessments included cardiopulmonary exercise testing, medical and lifestyle history plus socioeconomic status. Additionally, the participants completed a psychological questionnaire regarding their attitude, subjective norms, perceived behavior control and intention towards PA. A multivariate logistic regression model was used to identify predictors for participants reaching their age- and sex-adjusted VO_2peak reference values. 22 participants (median age: 40 years, interquartile range (IQR) 33–46) were cancer-unaffected and 46 cancer-affected (median age: 44 years, IQR 35–50). The strongest predictor for reaching the reference VO_2peak value was attitude towards PA (Odds Ratio 3.0; 95% Confidence Interval 1.3–8.4; p = 0.021). None of the other predictors showed a significant association. A positive attitude towards PA seems to be associated with VO_2peak, which should be considered in developing therapeutic and preventive strategies.

Trial registrations: NCT02087592; DRKS00005736.

Medical knowledge and information needs among women with pathogenic variants in moderate-risk genes for hereditary breast cancer attending genetic counseling at an academic hospital in Germany-A qualitative approach

With 69,000 newly diagnosed cases every year, breast cancer (BC) is the most frequent cancer disease among women in Germany. Familial clustering is seen in about 30% of newly diagnosed cases. Besides the high-risk genes BRCA1/2, there are also moderate-risk BC genes (MBCG) that are associated with a 20%-50% risk of BC, such as CHEK2, ATM, and PALB2. In Germany, carriers of pathogenic variants in MBCG receive specific information on their test results, individual risks, and preventive options during genetic counseling for the disclosure of the results in a specialized center. Little is known about the medical knowledge that women have after attending counseling. This study aims to identify the medical knowledge, further information needs, and the possible impact of a lack of information on dealing with everyday life for women with pathogenic variants in MBCG who have attended genetic counseling at an academic hospital in Germany. Problem-centered, guided, individual interviews were conducted with twelve women carrying pathogenic variants in MBCG. The interview guide was developed based on the methods of the problem-centered interview according to Witzel. The interview analysis was based on Mayring's qualitative content analysis. The women were between 29 and 59 years old and carried pathogenic variants in the risk genes CHEK2 (n = 8), ATM (n = 1), or PALB2 (n = 3). Several medical uncertainties and information needs emerged from the data, concerning (a) medical terms, (b) risk perception, (c) BC therapy for hereditary BC, (d) lifestyle advice and risk factors, and (e) family planning and risk-reducing mastectomy. Women with pathogenic variants in MBCG might develop their own conceptions regarding the onset of disease and inheritance. In order to meet the need for information and address the uncertainties that may still exist after genetic counseling, structured, evidence-based and comprehensible written information in German should be developed for this group.

Lifestyle modifications after the diagnosis of gynecological cancer

Background

The influence of lifestyle factors on the quality of life, incidence and tumor recurrence has been evaluated in several studies and is gaining increasing importance in cancer research. However, the extent of the influence of such lifestyle factors on the quality of life of cancer patients remains largely unclear, as does the number of patients actually pursuing these lifestyle changes. The purpose of this study was to examine the prevalence and predictors of lifestyle changes in patients with gynecological cancer.

Methods

The survey consisted of a pseudonymous questionnaire that was conducted from January to May 2014 via a telephone interview with 141 patients with a gynaecological malignancy who had undergone surgery at our Department of Gynaecology and Obstetrics. Lifestyle factors (diet, physical activity, stress level, alcohol and nicotine consumption) prior to and after the diagnosis of cancer were evaluated.

Results

89% (n = 125) of the patients reported lifestyle changes after being diagnosed with cancer. There was a significant association between the implementation of lifestyle changes and age as well as the use of complementary medicine. Nutrition: 66% of the patients (n = 93) consumed more fruit and vegetables and 65% ate less meat (n = 92). Physical activity: 37% (n = 52) reported no change in their exercise routine, 36% (n = 51) described a decrease, 27% (n = 38) an increase in their physical activity. Subjective feeling of stress: 77% of the patients (n = 108) described a reduction in their perceived level of stress. Nicotine consumption: 63% (n = 12) of the 19 patients who were smokers at the time of the diagnosis quit or reduced smoking thereafter. Alcohol consumption: 47% (n = 61/129) of the patients reduced their alcohol consumption.

Conclusions

Most of the patients from our study group implemented lifestyle changes after being diagnosed with cancer. Prospective randomized trials are needed in order to determine the benefit of lifestyle changes (physical activity, dietary habits and stress reduction) for cancer survivors. The potential impact of lifestyle on the quality of life and the trajectory of the disease should be discussed with all oncological patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12905-021-01391-5.

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.

Beneficial Molecular Adaptations In BRCA-Mutation Carriers By Combined HIT/HIRT Intervention: Results From A Pilot Study

Based on growing evidence that breast cancer (BRCA) also plays a pivotal role in the regulation of skeletal muscle metabolism and the response to anti-oxidative stress, we examined the influence of regular exercise in human BRCA mutation carriers on their BRCA1 gene/protein expression and inflammatory/oxidative response. Sixteen BRCA-mutation carriers were assigned to an intervention (IG) or control group (CG). IG received a combination of high-intensity interval endurance (HIT) and strength training (HIRT) for six weeks, whereas CG received a low-intensity activity program. Before (T0) and at the end of the intervention (T1), muscle biopsy, physiological performance, blood withdrawal and anthropometry were obtained. Parameters included: Muscle BRCA1 gene/protein expression, inflammatory/oxidative stress, anti-oxidative capacity, peak oxygen capacity (VO₂peak) and 1-repetition maximum (1-RM) at six different training machines. VO₂peak and 1-RM of IG were increased at T1 compared to T0, whereas CG performance, physiological and molecular parameters remained unchanged. IG showed increased BRCA1 protein concentration as well as anti-oxidative capacity, whereas gene expression was unaltered. IG inflammatory and oxidative damage did not differ between time points. Combined HIT/HIRT increases aerobic and strength performance of BRCA-mutation carriers with up regulated BRCA1 protein expression and improved anti-oxidative status without showing an increased inflammatory response.

Effectiveness of decision aids for female BRCA1 and BRCA2 mutation carriers: a systematic review

BACKGROUND

Female BRCA1 and BRCA2 mutation carriers have an increased lifetime risk of developing breast and/or ovarian cancer. Hence, they face the difficult decision of choosing a preventive strategy such as risk-reducing surgeries or intensified breast screening. To help these women during their decision process, several patient decision aids (DA) were developed and evaluated in the last 15 years. Until now, there is no conclusive evidence on the effectiveness of these DA. This study aims 1) to provide the first systematic literature review about DA addressing preventive strategy decisions for female BRCA1 and BRCA2 mutation carriers, 2) to analyze the quality of the existing evidence, 3) to evaluate the effects of DA on decision and information related outcomes, on the actual choice for preventive measure and on health outcomes.

METHODS

A systematic literature review was conducted using six electronic databases (inclusion criteria: DA addressing preventive strategies, female BRCA1 and BRCA2 mutation carriers, 18 to 75 years, knowledge of test result). The quality of the included randomized controlled trials (RCT) was evaluated with the Cochrane Collaboration's risk of bias tool. The quality of included one-group pretest-posttest design studies was evaluated with the ROBINS-I tool. Outcomes of included studies were extracted and qualitatively summarized.

RESULTS

A total of 2093 records were identified. Six studies were included for further evaluation (5 RCT, 1 one-group pretest-posttest design study). One RCT was formally included, but data presentation did not allow for further analyses. The risk of bias was high in three RCT and unclear in one RCT. The risk of bias in the one-group pretest-posttest study was serious. The outcome assessment showed that the main advantages of DA are linked to the actual decision process: Female BRCA1 and BRCA2 mutation carriers using a DA had less decisional conflict, were more likely to reach a decision and were more satisfied with their decision.

CONCLUSIONS

Decision aids can support female BRCA1 and BRCA2 mutation carriers during their decision process by significantly improving decision related outcomes. More high-quality evidence is needed to evaluate possible effects on information related outcomes, health outcomes and the actual choice for preventive measures.

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.

Physical activity during adolescence and young adulthood and the risk of breast cancer in BRCA1 and BRCA2 mutation carriers

BACKGROUND

Physical activity is inversely associated with the risk of breast cancer among women in the general population. It is not clear whether or not physical activity is associated with the risk of BRCA-associated breast cancer.

METHODS

We conducted a case-control study of 443 matched pairs of BRCA mutation carriers to evaluate the association between physical activity and breast cancer risk. Moderate and vigorous physical activities at ages 12-13, ages 14-17, ages 18-22, ages 23-29 and ages 30-34 were determined using the Nurses' Health Study II Physical Activity Questionnaire. We estimated mean metabolic equivalent task hours/week for moderate, vigorous and total physical activities overall (ages 12-34), during adolescence (ages 12-17) and during early adulthood (ages 18-34). Logistic regression analysis was used to estimate the odds ratios (OR) and 95% confidence intervals (CI) for total, moderate and strenuous recreational physical activities and breast cancer risk, by menopausal status.

RESULTS

Overall, there was no significant association between total physical activity and subsequent breast cancer risk (OR_{Q4 vs. Q1} = 1.01, 95% CI 0.69-1.47; P-trend = 0.72). Moderate physical activity between ages 12-17 was associated with a 38% decreased risk of premenopausal breast cancer (OR_{Q4 vs. Q1} = 0.62; 95% CI 0.40-0.96; P-trend = 0.01). We found no association between exercise and breast cancer diagnosed after menopause.

CONCLUSIONS

These findings suggest that early-life physical activity is associated with a reduced risk of premenopausal breast cancer among BRCA mutation carriers.

IMPACT

Future prospective analyses, complemented by mechanistic evidence, are warranted in this high-risk population.