Insulin, Physical Activity, and Caloric Intake in Postmenopausal Women: Breast Cancer Implications

A review of research on the intersection between breast cancer and cardiovascular research in the Women's Health Initiative (WHI)

Both obesity and metabolic syndrome are linked to increased incidence of type 2 diabetes, cardiovascular disease (CVD), and cancers of the breast (post-menopausal), and other obesity-related cancers. Over the past 50 years, the worldwide prevalence of obesity and metabolic syndrome has increased, with a concomitant higher incidence of associated co-morbidities and mortality. The precise mechanism linking metabolic syndrome to increased cancer incidence is incompletely understood, however, individual components of metabolic syndrome have been linked to increased breast cancer incidence and worse survival. There is a bidirectional relationship between the risk of CVD and cancer due to a high burden of shared risk factors and higher rates of CVD among cancer survivors, which may be impacted by the pro-inflammatory microenvironment associated with metabolic syndrome and cancer-directed therapies. The Women's Health Initiative (WHI) is an excellent resource to study a dual relationship between cancer and CVD (cardio-oncology) with extensive information on risk factors and long-term outcomes. The purpose of this review is to provide an overview of research on cardio-oncology conducted utilizing WHI data with focus on studies evaluating both breast cancer and CVD including shared risk factors and outcomes after cancer. The review also includes results on other obesity related cancers which were included in the analyses of breast cancer, articles looking at cancer after heart disease (reverse cardio-oncology) and the role of Clonal Hematopoiesis of Indeterminate Potential (CHIP) as a shared risk factor between CVD and cancer. A summary of pertinent WHI literature helps to delineate the direction of future research evaluating the relationship between CVD and other cancer sites, and provides information on the opportunity for other novel analyses within the WHI.

Metabolic consequences of perioperative oral carbohydrates in breast cancer patients - an explorative study

Background

The metabolic consequences of preoperative carbohydrate load in breast cancer patients are not known. The present explorative study investigated the systemic and tumor metabolic changes after preoperative per-oral carbohydrate load and their influence on tumor characteristics and survival.

Methods

The study setting was on university hospital level with primary and secondary care functions in south-west Norway. Serum and tumor tissue were sampled from a population-based cohort of 60 patients with operable breast cancer who were randomized to either per-oral carbohydrate load (preOp™; n = 25) or standard pre-operative fasting (n = 35) before surgery. Magnetic resonance (MR) metabolomics was performed on serum samples from all patients and high-resolution magic angle spinning (HR-MAS) MR analysis on 13 tumor samples available from the fasting group and 16 tumor samples from the carbohydrate group.

Results

Fourteen of 28 metabolites were differently expressed between fasting and carbohydrate groups. Partial least squares discriminant analysis showed a significant difference in the metabolic profile between the fasting and carbohydrate groups, compatible with the endocrine effects of insulin (i.e., increased serum-lactate and pyruvate and decreased ketone bodies and amino acids in the carbohydrate group). Among ER-positive tumors (n = 18), glutathione was significantly elevated in the carbohydrate group compared to the fasting group (p = 0.002), with a positive correlation between preoperative S-insulin levels and the glutathione content in tumors (r = 0.680; p = 0.002). In all tumors (n = 29), glutamate was increased in tumors with high proliferation (t-test; p = 0.009), independent of intervention group. Moreover, there was a positive correlation between tumor size and proliferation markers in the carbohydrate group only. Patients with ER-positive / T2 tumors and high tumor glutathione (≥1.09), high S-lactate (≥56.9), and high S-pyruvate (≥12.5) had inferior clinical outcomes regarding relapse-free survival, breast cancer-specific survival, and overall survival. Moreover, Integrated Pathway Analysis (IPA) in serum revealed activation of five major anabolic metabolic networks contributing to proliferation and growth.

Conclusions

Preoperative carbohydrate load increases systemic levels of lactate and pyruvate and tumor levels of glutathione and glutamate in ER-positive patients. These biological changes may contribute to the inferior clinical outcomes observed in luminal T2 breast cancer patients.

Trial of registration

ClinicalTrials.gov; NCT03886389. Retrospectively registered March 22, 2019.

Healthy lifestyle impact on breast cancer-specific and all-cause mortality

PURPOSE

While several studies have evaluated the association of combined lifestyle factors on breast cancer-specific mortality, few have included Hispanic women. We constructed a "healthy behavior index" (HBI) and evaluated its associations with mortality in non-Hispanic White (NHW) and Hispanic women diagnosed with breast cancer from the southwestern U.S.

METHODS

Diet and lifestyle questionnaires were analyzed for 837 women diagnosed with invasive breast cancer (1999-2004) in New Mexico as part of the 4-Corners Women's Health Study. An HBI score ranging from 0 to 12 was based on dietary pattern, physical activity, smoking, alcohol consumption, and body size and shape, with increasing scores representing less healthy characteristics. Hazard ratios for mortality over 14 years of follow-up were estimated for HBI quartiles using Cox proportional hazards models adjusting for education and stratified by ethnicity and stage at diagnosis.

RESULTS

A significant increasing trend was observed across HBI quartiles among all women, NHW women, and those diagnosed with localized or regional/distant stage of disease for all-cause (AC) mortality (p-trend = 0.006, 0.002, 0.03, respectively). AC mortality was increased >2-fold for all women and NHW women in HBI Q4 versus Q1 (HR = 2.18, 2.65, respectively). The association was stronger in women with regional/distant than localized stage of disease (HR = 2.62, 1.94, respectively). Associations for Hispanics or breast cancer-specific mortality were not significant.

CONCLUSIONS

These findings indicate the associations between the HBI and AC mortality, which appear to differ by ethnicity and stage at diagnosis. Interventions for breast cancer survivors should address the combination of lifestyle factors on prognosis.

Exercise after breast cancer treatment: current perspectives

Over the past 2 decades, great strides have been made in the field of exercise-oncology research, particularly with breast cancer. This area of research is particularly important since there are >2.8 million breast cancer survivors who are in need of an intervention that can offset treatment-related side effects. Noticeable reductions in physical fitness (ie, cardiopulmonary fitness and muscular strength), negative changes in body composition (ie, increase in body mass, decrease in lean body mass, and increase in fat mass), increased fatigue, depression, or anxiety are some of the common side effects of cancer treatments that negatively impact overall quality of life and increase the risk for the development of comorbidities. Exercise plays a vital role in improving cardiopulmonary function, psychological events, muscular strength, and endurance in breast cancer survivors, and thus should be considered as a key factor of lifestyle intervention to reverse negative treatment-related side effects. The purpose of this review is to address current perspectives on the benefits of aerobic and resistance exercise after breast cancer treatments. This review is focused on the well-established benefits of exercise on physical and emotional well-being, bone health, lymphedema management, and the postulated benefits of exercise on risk reduction for recurrence of breast cancer.

Nutrition and physical activity influence on breast cancer incidence and outcome

INTRODUCTION AND AIMS

To provide a current perspective on nutrition and physical activity influence on breast cancer.

METHODS AND RESULTS

A comprehensive literature review was conducted and selective presentation of findings follows. While some observational studies have associated higher dietary fat intake with higher breast cancer incidence, two full-scale randomized, clinical trials of dietary fat intake reduction programs were negative. However, a lifestyle intervention targeting fat intake reduction in the Women's Intervention Nutrition Study (WINS), resulted in weight loss and also reduced breast cancer recurrences in women with early stage disease. Observational studies evaluating specific nutrient intakes and dietary supplements have provided mixed results. Several observational studies find women with early stage breast cancer with lower 25-hydroxyvitamin D levels at higher recurrence risk, a finding requiring cautious interpretation. The lifestyle factor most strongly and consistently associated with both breast cancer incidence and breast cancer recurrence risk is physical activity. A meta-analyses of observational studies supports the concept that moderate recreational physical activity (about 3-4 h walking per week) may reduce breast cancer incidence and that women with early stage breast cancer who increased or maintain their physical activity may have lower recurrence risk as well. Feasibility of achieving increased physical activity and weight loss in women with early-stage breast cancer has been established. Two full-scale randomized clinical trials are evaluating weight loss/maintenance and increased physical activity in relation to recurrence risk in women with early-stage, resected breast cancer.

DISCUSSION/CONCLUSIONS

Dietary intake may influence breast cancer but influence is difficult to separate from influence of body weight. A consistent body of observational study evidence suggests higher physical activity has favorable influence on breast cancer incidence and outcome. While awaiting definitive evidence from ongoing randomized trials, breast cancer patients can reasonably be counseled to avoid weight gain and reduce body weight if overweight or obese and increase or maintain a moderate level of physical activity.

[Relation between physical activity, weight balance and breast cancer]

Many epidemiologic studies, with a good methodology, support the evidence of the positive role of regular physical activity on primary and tertiary prevention of breast cancer on the risk of recurrence and mortality. This relation depends on the level of total energy expenditure by week, which helps balance weight on lifetime, an essential part of benefit. The beneficial effects of physical activity are linked to many interrelated additional mechanisms: in a short-term, contraction of skeletal muscles involves aerobic metabolism which utilizes glucose and amino acids like glutamine, improves insulin sensitivity and lowers plasma insulin; in a long-term, physical activity produces favorable changes in body composition, decreasing body fat and increasing lean mass. That is a key point to reduce the intake of energy substrates stimulating carcinogenesis, to improve insulin sensitivity, to change the ratio of leptin and adiponectin, to enhance cellular immunity and to block cellular pathways of cell proliferation and angiogenesis. Maintaining a healthy weight through regular physical activity well balanced with energy intake is it a goal for prevention of breast cancer.

Insulinemia and the risk of breast cancer and its relapse

A fairly large body of evidence has shown that insulin is a tumour-promoting agent, especially for breast cancer. High circulating and microenvironmental levels of insulin may directly increase the risk of breast cancer via the activation of cognate receptors expressed on normal and cancer cells and indirectly be associated with other known metabolic risk factors of cancer that usually are present in conjunction with the hyperinsulinic state. The focus of this review is to analyse and discuss available data in the literature on the possible causative/prognostic role of insulin resistance/hyperinsulinemia in breast cancer development and progression.

Recreational physical activity in postmenopausal women is stable over 8 years of follow-up

BACKGROUND

The goals of this study were to examine 1) longitudinal trajectories of energy expenditure from recreational physical activity (PA) in postmenopausal women, 2) whether women who belong to different PA trajectories engage in different types of PA, and 3) whether baseline sociodemographic, health, psychosocial, and lifestyle characteristics predict membership in PA trajectories.

METHODS

Women from the Women's Health Initiative Observational Study with baseline PA data (n = 92,629) were included. Physical activity, measured via self-report 6 times over 8 years, was converted to MET hr/wk for analysis. Latent growth curve mixture models and latent profile models were used to analyze longitudinal PA trajectories and cross-sectional PA composition, respectively.

RESULTS

Three distinct, stable PA trajectories (highly, moderately, and minimally active) were identified with nearly 75% of the women classified as minimally active (≤ 8 MET-hr/wk). The majority of women who were at least moderately active engaged in a balanced combination of walking, moderate, and vigorous PA. Sociodemographic characteristics such as income, education, and past vigorous PA were predictive of PA trajectory, as were some health status indicators (eg, body mass index), but not health related quality of life.

CONCLUSIONS

Self-reported PA is largely stable across nearly a decade of follow-up in postmenopausal women.

Development of a dish-based, semi-quantitative FFQ for the Korean diet and cancer research using a database approach

We used a database approach in developing a dish-based, semi-quantitative FFQ for Korean diet and cancer research. Cancer-related dietary factors (CRDF) recognised in the scientific community and dietary intake data from the 2001 Korean National Health and Nutrition Examination Survey and the 2002 Korean National Nutrition Survey by Season were used. The list of dishes (n 993) was those reported to be consumed by individuals over 30 years of age during all four seasons. The resulting 112-dish list was selected using contribution analyses and variability analyses to detect between-person variation for CRDF and non-CRDF nutrients. Variations of each dish were grouped into one dish for the final list of 112 dishes, which were then linked to the nutrient database. The final 112 dish items consisted of nine Korean staple dishes, including rice and noodles, twenty-five soups and stews, fifty-four side dishes, nine beverages, nine fruit dishes and six alcoholic beverages. The percentage coverages of energy, protein, fat, carbohydrate and alcohol intake in the selected 112 dishes were 82·4, 76·4, 68·9, 86·0 and 99·8 %, respectively. Dietary exposure to cancer-related Korean dietary factors can be assessed by this new dish-based, semi-quantitative FFQ. This new instrument can calculate the intake of CRDF along with non-CRDF nutrient intake for cancer research.

Increasing physical activity among African-American women and girls

The benefits of physical activity on diseases and risk factors are well known. Despite the known benefits, many segments of the population, particularly African-American women and girls, do not obtain adequate levels of physical activity. Strategies are needed to identify successful and sustainable interventions to increase physical activity among this population. We reviewed literature published between 2007 and 2009 that focused on increasing physical activity or fitness among this population. We identified 37 studies, 11 of which focused on increasing physical activity. This article summarizes the findings from those 11 studies and provides recommendations for improving strategies to increase physical activity in African-American women and girls.

Diet, physical activity and energy balance and their impact on breast and prostate cancers

Obesity, physical activity status and circulating levels of sex steroid hormones and growth factor proteins are intrinsically linked to energy balance. Epidemiological studies have previously reported associations between these factors and the risk of hormone-related cancers such as prostate and breast cancer in men and postmenopausal women. An increasing number of intervention studies in 'at-risk' populations and cancer survivors are now investigating the effects of lifestyle interventions that promote negative energy balance on circulating levels of sex hormones and growth factor proteins as surrogate markers of cancer risk. Evidence from these studies suggests that lifestyle interventions can improve insulin sensitivity, alter the balance of circulating sex steroid hormones and insulin-like growth factor (IGF) axis proteins (including IGF-1 and the IGF binding proteins 1 and 3) and change the functioning of immune cells in peripheral blood. Such changes could influence the risk of developing hormone-related cancers, as well as having the potential to improve disease-free survival in patients recovering from cancer treatment. However, despite promising results, the methodological quality of most intervention studies has been limited due to small subject numbers, lack of adequate control groups or non-randomised designs and the absence of long-term follow-up measures. More intervention studies with randomised controlled designs, higher numbers of subjects and longer-term follow-up measures are needed to establish which combination of specific dietary and physical activity interventions work best for reducing risk in 'at-risk' populations and survivors, optimal dose-response relationships and the magnitude of change in surrogate markers of cancer risk that is required to induce a protective effect.

Repeated measures of serum glucose and insulin in relation to postmenopausal breast cancer

Experimental and epidemiological evidence suggests that circulating glucose and insulin may play a role in breast carcinogenesis. However, few cohort studies have examined breast cancer risk in association with glucose and insulin levels, and studies to date have had only baseline measurements of exposure. We conducted a longitudinal study of postmenopausal breast cancer risk using the 6% random sample of women in the Women's Health Initiative clinical trials whose fasting blood samples, provided at baseline and at years 1, 3 and 6, were analyzed for glucose and insulin. In addition, a 1% sample of women in the observational study, who had glucose and insulin measured in fasting blood samples drawn at baseline and in year 3, were included in the analysis. We used Cox proportional hazards models to estimate hazard ratios and 95% confidence intervals for the association of baseline and follow-up measurements of serum glucose and insulin with breast cancer risk. All statistical tests were 2-sided. Among 5,450 women with baseline serum glucose and insulin values, 190 incident cases of breast cancer were ascertained over a median of 8.0 years of follow-up. The highest tertile of baseline insulin, relative to the lowest, was associated with a 2-fold increase in risk in the total population (multivariable hazard ratio 2.22, 95% confidence interval 1.39-3.53) and with a 3-fold increase in risk in women who were not enrolled in the intervention arm of any clinical trial (multivariable hazard ratio 3.15, 95% confidence interval 1.61-6.17). Glucose levels showed no association with risk. Analysis of the repeated measurements supported the results of the baseline analysis. These data suggest that elevated serum insulin levels may be a risk factor for postmenopausal breast cancer.

Test-retest reliability of the Women's Health Initiative physical activity questionnaire

PURPOSE

Few physical activity (PA) questionnaires were designed to measure the lifestyles and activities of women. We sought to examine the test-retest reliability of a PA questionnaire used in the Women's Health Initiative (WHI) study. Differences in reliability were also explored by important covariates.

METHODS

Participants (n = 1092) were postmenopausal women aged 50-79 yr, randomly selected from the baseline sample of participants in the WHI Observational Study. The WHI PA questionnaire collects usual frequency, duration, and pace of recreational walking, frequency, and duration of other recreational activities or exercises (mild, moderate, and strenuous), household, and yard activities. Approximately half of the women (n = 569) repeated questions on recreational PA, the other half (n = 523) repeated questions related to household and yard activities (mean 3 months apart). Test-retest reliability was assessed with kappa and intraclass correlation coefficients (ICC 1,1).

RESULTS

Overall, questions on recreational walking, moderate recreational PA, and strenuous recreational PA had higher test-retest reliability (weighted kappa range = 0.50-0.60) than questions on mild recreational PA (weighted kappa range = 0.35-0.50). The ICC 1,1 for moderate to strenuous recreational PA was 0.77 (95% confidence interval [CI] = 0.73-0.80), and the total recreational PA was 0.76 (95% CI = 0.71-0.79). Substantial reliability was observed for the summary measures of yard activities (ICC 1,1 = 0.71; 95% CI = 0.66-0.75) and household activities (ICC 1,1 = 0.60, 95% CI = 0.55-0.66). No meaningful differences were observed by race/ethnicity, age, time between test and retest, and amount of reported PA.

CONCLUSIONS

The WHI PA questionnaire demonstrated moderate to substantial test-retest reliability in a diverse sample of postmenopausal women.

Weight History, Smoking, Physical Activity and Breast Cancer Risk among French-Canadian Women Non-Carriers of More Frequent BRCA1/2 Mutations

Several lifestyle factors play a significant role in determining an individual's risk of breast cancer. Many of them could be modified to protect against the malignancy. A nested case-control study was conducted to examine the association between selected lifestyle factors and non-BRCA-related breast cancer risk among French-Canadian women. Some 280 women with breast cancer and who were nongene carriers of mutated BRCA gene were recruited as cases. Another 280 women, without any cancer and nongene carriers of mutated BRCA gene served as controls. A tested lifestyle questionnaire was interviewer administered to incident cases to obtain information on weight history, smoking, physical activity, and other lifestyle risk factors. Odds ratios (ORs) and 95% confidence intervals (CIs) were estimated in logistic regression models. Comparing cases to controls, breast cancer risk was higher among subjects who reached their maximum body mass index (BMI) at an older age (>50 years) (OR = 2.83; 95% CI: 2.34–2.91). A positive association was noted between breast cancer risk and weight gain of >34 lbs compared to weight gain of ≤15 lbs, since the age of 20 (OR = 1.68; 95% CI: 1.10–2.58). Weight gain of >24 lbs compared to weight gain of ≤9 lbs, since the age of 30 also resulted in the same relationship (OR = 1.96; 95% CI: 1.46–3.06). Similarly, since the age of 40, weight gain of >12 lbs compared to weight gain of ≤1 lb was associated with increased breast cancer risk (OR = 1.91; 95% CI: 1.53–2.66). Women who smoked >9 pack-years of cigarettes had a 59% higher breast cancer risk (P = .05). Subjects who engaged in >24.8 metabolic-equivalent- (MET-) hours per week compared to ≤10.7 MET-hours per week of moderate physical activity had a 52% (P = .01) decreased risk and total physical activity between 16.2 and 33.2 MET-hours per week compared to ≤16.2 MET-hours per week, resulted in a 43% (P = .05) lower risk of breast cancer. In conclusion, weight history did affect breast cancer risk. Moreover, smoking appeared to raise the risk, whereas moderate physical activity had a protective effect.

Energy balance and type 2 diabetes: a report from the Shanghai Women's Health Study

BACKGROUND AND AIMS

The combined effect of the components of energy balance (energy intake and physical activity) and the development of type 2 diabetes (T2D) has not been adequately investigated. The aim of this study was to examine the components of energy balance and the incidence of T2D in a cohort of middle-aged women.

METHODS AND RESULTS

A population-based prospective study of 64,227 middle-aged Chinese women who had no prior history of diabetes or chronic disease at study recruitment. Participants completed in-person interviews at baseline and follow-up surveys that collected information on diabetes risk factors including dietary and physical activity habits and disease occurrence. Anthropometric measurements were taken by trained interviewers at recruitment. Average follow-up time was 4.6 years. During 297,755 person-years of follow-up, 1608 new cases of T2D were documented. Body mass index (BMI) and weight gain (since age 20) were strongly associated with T2D incidence. Energy intake (EI) was associated with modestly increased risk, while physical activity (PA) was associated with decreased risk of T2D. Less active women with higher EI had higher risk of T2D (RR=1.96; 95% CI: 1.44, 2.67) than active women with lower EI (P(interaction)=0.02). The EI to PA (EI:PA) ratio was positively associated with T2D risk; the association was more evident among overweight and obese women (BMI > or = 23 kg/m(2)).

CONCLUSION

These data suggest that energy balance plays an important role in the development of T2D, and this effect may be modified by BMI.

Joint effects of body size, energy intake, and physical activity on breast cancer risk

To evaluate the joint effect of body size, energy intake, and physical activity on breast cancer risk, we analyzed information on body weight history, energy intake, anthropometric measurements, and physical activity patterns in a population based case-control study. Included in this analysis were 3,458 incidence breast cancer cases and 3,474 age-frequency matched controls from the Shanghai Breast Cancer Study. High weight, height, body mass index, waist-to-hip ratio, and weight gain showed stronger associations with breast cancer risk in postmenopausal women than premenopausal women. High total physical activity was inversely associated with postmenopausal breast cancer risk (p for trend=0.026) and premenopausal breast cancer (p for trend=0.059). The odds ratios for women with a high waist-to-hip ratio (>or=0.84) and low total physical activity (<or=10.9 MET-h/day) had the highest risk for breast cancer (OR=2.7, 95% CI: 1.4-4.9 for postmenopausal women, OR=2.1, 95% CI: 1.5-3.1 for premenopausal women) compared to their counterpart with low waist-to-hip ratio (<0.76) and high total physical activity (>20.5 MET-h/day). We did not find a statistically significant multiplicative interaction between body size, caloric intake and total physical activity on breast cancer risk.

Design of the sex hormones and physical exercise (SHAPE) study

Background

Physical activity has been associated with a decreased risk for breast cancer. The biological mechanismn(s) underlying the association between physical activity and breast cancer is not clear. Most prominent hypothesis is that physical activity may protect against breast cancer through reduced lifetime exposure to endogenous hormones either direct, or indirect by preventing overweight and abdominal adiposity. In order to get more insight in the causal pathway between physical activity and breast cancer risk, we designed the Sex Hormones and Physical Exercise (SHAPE) study. Purpose of SHAPE study is to examine the effects of a 1-year moderate-to-vigorous intensity exercise programme on endogenous hormone levels associated with breast cancer among sedentary postmenopausal women and whether the amount of total body fat or abdominal fat mediates the effects.

Methods/Design

In the SHAPE study, 189 sedentary postmenopausal women, aged 50–69 years, are randomly allocated to an intervention or a control group. The intervention consists of an 1-year moderate-to-vigorous intensity aerobic and strenght training exercise programme. Partcipants allocated to the control group are requested to retain their habitual exercise pattern. Primary study parameters measured at baseline, at four months and at 12 months are: serum concentrations of endogenous estrogens, endogenous androgens, sex hormone binding globuline and insuline. Other study parameters include: amount of total and abdominal fat, weight, BMI, body fat distribution, physical fitness, blood pressure and lifestyle factors.

Discussion

This study will contribute to the body of evidence relating physical activity and breast cancer risk and will provide insight into possible mechanisms through which physical activity might be associated with reduced risk of breast cancer in postmenopausal women.

Trial registration

NCT00359060

Dietary fat reduction and breast cancer outcome: results from the Women's Intervention Nutrition Study (WINS)

Given that existing epidemiologic data on the correlation between dietary fat and breast cancer have been mixed, the Women's Intervention Nutrition Study was launched in 1987. This randomized clinical trial of 2437 women between the ages of 48 and 79 y with early-stage breast cancer tested the hypothesis that dietary fat reduction would increase the relapse-free survival rate. The study determined that low-fat dietary interventions can influence body weight and decrease breast cancer recurrence. Results showing a differential effect of diet on hormone-receptor-positive and -negative disease suggest that metabolic mechanisms involving insulin and insulin-like growth factor-1 may be involved in tumorigenesis. The results of the Women's Intervention Nutrition Study may therefore contribute to knowledge of the role of insulin resistance in cancer risk.

Physical activity and risk of endometrial cancer: the European prospective investigation into cancer and nutrition

The etiologic role of physical activity in endometrial cancer risk remains unclear given the few epidemiologic studies that have been conducted. To investigate this relation more fully, an analysis was undertaken in the European prospective investigation into cancer and nutrition (EPIC). During an average 6.6 years of follow-up, 689 incident endometrial cancer cases were identified from an analytic cohort within EPIC of 253,023 women. Cox proportional hazards models were used to estimate the associations between type of activity (total, occupational, household, recreational) and endometrial cancer risk. For total activity, women in the highest compared with the lowest quartile of activity had a risk of 0.88 (95% confidence interval (95% CI=0.61-1.27). No clear associations between each type of activity and endometrial cancer risk were found for the total study population combined. Associations were more evident in the stratified results, with premenopausal women who were active versus inactive experiencing a risk of 0.66 (95% CI=0.38-1.14) overall. Among premenopausal women, for household and recreational activities the risk estimates in the highest as compared with the lowest quartiles were, respectively, 0.48 (95% CI=0.23-0.99) and 0.78 (95% CI=0.44-1.39). No effect modification by body mass index, hormone replacement therapy, oral contraceptive use or energy intake was found. This study provides no evidence of a protective effect of increased physical activity in endometrial cancer risk in all women but some support for a benefit among premenopausal women. The relative risk reductions are most apparent for household activities.

Physical activity and breast cancer risk among women in the southwestern United States

Physical activity may influence breast cancer risk through multiple mechanisms and at different periods in life. In this study we evaluate breast cancer risk associated with total and vigorous physical activity at ages 15, 30, and 50 years and the referent year prior to diagnosis/selection. Participants were non-Hispanic white (NHW) (1527 cases and 1601 control subjects) and Hispanic/American Indian (HAI) (798 cases and 924 controls) women. Both total and vigorous activity reduced risk of breast cancer in a dose-response manner. Among premenopausal women, only high total metabolic equivalent of the task (MET) hours of activity during the referent year was associated with reduced breast cancer risk in NHW women (odds ratio [OR] 0.62; 95% confidence interval [CI] 0.43, 0.91). Among postmenopausal women, physical activity had the greatest influence among women not recently exposed to hormones. Among these women, high total lifetime activity reduced risk of breast cancer for both NHW (OR 0.60; 95% CI 0.36, 1.02; p trend 0.01) and HAI women (OR 0.52; 95% CI 0.23, 1.16; p trend 0.07). Additionally, high total MET hours of activity at age 30 years (OR 0.56; 95% CI 0.37, 0.85) and at age 15 years (OR 0.57; 95% CI 0.38, 0.88) reduced breast cancer risk among postmenopausal NHW women not recently exposed to hormones. Among HAI women, more recent activity performed during the referent year and at age 50 appeared to have the greatest influence on breast cancer risk. Among postmenopausal NHW women. there was a significant interaction between physical activity and hormone replacement therapy (p value, 0.01), while among postmenopausal HAI women, physical activity interacted with body mass index (p value, 0.04). These data suggest that physical activity is important in reducing risk of breast cancer in both NHW and HAI women.

Lifetime recreational and occupational physical activity and risk of in situ and invasive breast cancer

Numerous studies have observed reduced breast cancer risk with increasing levels of physical activity, yet these findings have been inconsistent about optimal times of activity and effect modification by other factors. We investigated the association between recreational and occupational physical activity and breast cancer risk in a population-based case-control study in Massachusetts, New Hampshire, and Wisconsin. During structured telephone interviews, 7,630 controls, 1,689 in situ, and 6,391 invasive breast cancer cases, ages 20 to 69 years, reported lifetime history of recreational physical activity and occupation. Neither lifetime recreational nor strenuous occupational physical activity appeared to be associated with risk of breast carcinoma in situ. In contrast, recreational physical activity was associated with a reduced risk of invasive breast cancer. After adjustment for potentially confounding factors, women averaging >6 h per week of strenuous recreational activity over their lifetime had a 23% reduction in the odds ratio of invasive breast cancer when compared with women reporting no recreational activity (95% confidence interval, 0.65-0.92; P(trend) = 0.05). However, this reduction in risk was limited to women without a first-degree family history of breast cancer (P(interaction) = 0.02). Inverse associations were observed for physical activity early in life, in the postmenopausal years, and in the recent past, but these findings were confined to women without a family history of breast cancer. Lifetime strenuous occupational activity was not associated with invasive breast cancer risk. These results provide further evidence that, for most women, physical activity may reduce the risk of invasive breast cancer.

Serum levels of C-peptide, IGFBP-1 and IGFBP-2 and endometrial cancer risk; Results from the European prospective investigation into cancer and nutrition

We conducted a case-control study nested within the European Prospective Investigation into Cancer and Nutrition, to examine the associations between prediagnostic serum concentrations of C-peptide, insulin-like growth factor binding protein (IGFBP)-1 and IGFBP-2, and endometrial cancer risk. Among pre- and post-menopausal women, who were not currently using exogenous hormones, 286 women developed incident endometrial cancer during an average 5.1 years follow-up. Using risk set sampling, 555 matched control subjects were selected. In conditional logistic regression models adjusted for matching factors only, endometrial cancer risk increased with increasing serum levels of C-peptide (relative risks (RR) for the top vs. bottom quartile = 2.13 [95% confidence interval (CI) 1.33-3.41], p(trend) = 0.001, and decreasing serum levels of IGFBP-2 (RR for the top vs. bottom quartile = 0.56 [95% CI 0.35-0.90], p(trend) = 0.03, but was not significantly associated with IGFBP-1 levels (RR for the top vs. bottom quartile = 0.76 [95% CI 0.47-1.21], p(trend) = 0.25). In BMI-adjusted models, only the C-peptide association remained marginally statistically significant (RR for the top vs. bottom quartile = 1.56 [95% CI 0.94-2.57], p(trend) = 0.05 for C-peptide; 0.84 [95% CI 0.50-1.40], p(trend) = 0.74 for IGFBP-2; and 1.08 [95% CI 0.65-1.78], p(trend) = 0.86 for IGFBP-1 levels). These associations were stronger among nonfasting women (< or =< or =6 hr since last meal; 63% of subjects) but were not evident among fasting women, although the interactions were not statistically significant. The C-peptide-risk association was substantially attenuated after adjustment for free estradiol in postmenopausal women (RR for the top vs. bottom quartile = 1.28 [95% CI 0.67-2.45], p(trend) = 0.42. Our results provide modest support to the hypothesis that hyperinsulinaemia is a risk factor for endometrial cancer.

C-Reactive Protein in Nipple Aspirate Fluid

BACKGROUND

Proteins expressed in nipple aspirate fluid (NAF) have been associated with breast cancer risk and may serve to detect inflammatory or premalignant states. Obesity, hyperlipidemia, and metabolic syndrome are associated with increased rates of breast cancer and are systemic markers of chronic inflammation.

OBJECTIVE

The aim of this study was to determine if one NAF protein, C-reactive protein (CRP), associated elsewhere in the human with cancer, relates to reproductive, nutrition, and body composition and activity factors.

METHODS

Women (n = 59) aged 30 to 64 years from the midwestern United States and Kenya were evaluated regarding the relation between reproductive (age, pregnancy, and breast-feeding indices), nutrition (serum lipids, serum, or NAF carotenoid), body composition and activity (activity, waist-hip ratio, fat percentage (% fat), and body mass index [BMI]) factors and CRP in NAF.

RESULTS

Age at first pregnancy (p < .05), gravidity (p < .05), wean time from breast-feeding last baby (p < .05), serum triglycerides (p = .01), % fat (p < .05), and BMI (p < .05) were related significantly to CRP levels in NAF. A model derived from selective women's reproductive, nutritional, and body composition and activity factors significantly (p < .05) accounted for the variance in breast microenvironment inflammation as measured by CRP in NAFs.

DISCUSSION

Detecting CRP in NAF may indicate local mammary inflammation, which has been associated with carcinogenesis. Specific NAF risk modeling that addresses reproductive, nutritional, and body composition and activity factors may be used for further advances in the prevention of breast cancer and the early detection and treatment of the disease.

Serum C-peptide levels and breast cancer risk: results from the European Prospective Investigation into Cancer and Nutrition (EPIC)

It has been hypothesized that chronic hyperinsulinemia, a major metabolic consequence of physical inactivity and excess weight, might increase breast cancer risk by direct effects on breast tissue or indirectly by increasing bioavailable levels of testosterone and estradiol. Within the European Prospective Investigation into Cancer and Nutrition (EPIC), we measured serum levels of C-peptide--a marker for pancreatic insulin secretion--in a total of 1,141 incident cases of breast cancer and 2,204 matched control subjects. Additional measurements were made of serum sex hormone binding globulin (SHBG) and sex steroids. Conditional logistic regression models were used to estimate breast cancer risk for different levels of C-peptide. C-peptide was inversely correlated with SHBG and hence directly correlated with free testosterone among both pre and postmenopausal women. C-peptide and free estradiol also correlated positively, but only among postmenopausal women. Elevated serum C-peptide levels were associated with a nonsignificant reduced risk of breast cancer diagnosed up to the age of 50 years [odds ratio (OR)=0.70, (95% confidence interval (CI), 0.39-1.24); ptrend=0.05]. By contrast, higher levels of C-peptide were associated with an increase of breast cancer risk among women above 60 years of age, however only among those women who had provided a blood sample under nonfasting conditions [OR=2.03, (95% CI, 1.20-3.43); ptrend=0.01]. Our results do not support the hypothesis that chronic hyperinsulinemia generally increases breast cancer risk, independently of age. Nevertheless, among older, postmenopausal women, hyperinsulinemia might contribute to increasing breast cancer risk.

Optimizing outcomes and quality of life in the hormonal treatment of prostate cancer

We review the effectiveness of androgen-deprivation therapy (ADT) in the management of prostate cancer, and the effect that this treatment has on a patient's quality of life (QoL), based on discussions held at a European symposium on the management of prostate cancer. The overall QoL is reduced in asymptomatic men, and there are known decreases in cognitive function, self-esteem, libido and sexual function. Hot flashes are also a frequent problem. Prolonged ADT can lead to osteoporosis and subsequently fractures. Various effective methods exist to manage and minimize these side-effects; some are specific to the side-effect, whereas other more general methods include lifestyle changes, specific drugs and added hormonal manipulations. Intermittent ADT for patients taking luteinizing hormone-releasing hormone agonists offers a promising method to reduce adverse effects, and possibly increases the time to androgen independence. Initial studies indicate that prostate-specific antigen-based progression with intermittent ADT is similar to that seen with continuous ADT, but there is a reduction in side-effects, leading to an improvement in QoL.