Can obesity explain the racial difference in stage of breast cancer at diagnosis between black and white women?

A Public Health Emergency: Breast Cancer Among Black Communities in the United States

While Black people have a similar incidence of breast cancer compared to White people, they have a 40% increased death rate. Black people are more likely to be diagnosed with aggressive subtypes such as triple-negative breast cancer. However, despite biological factors, systemic racism and social determinants of health create delays in care and barriers to treatment. While genetic testing holds incredible promise for Black people, uptake remains low and results may be challenging to interpret. There is a need for more robust, multidisciplinary, and antiracist interventions to reverse breast cancer-related racial disparities.

Disparities in the Use of Sentinel Lymph Node Dissection for Early Stage Breast Cancer

BACKGROUND

Clinical trials have long established the long-term safety of omitting axillary lymph node dissection (ALND) after sentinel lymph node dissection (SLND) in patients with clinically node-negative early stage breast cancer. The variations in utilization of SLND and ALND in this patient population, however, are currently unknown.

METHODS

Adult female patients (40 years and older) within the National Cancer Database diagnosed with breast cancer between January 2013 and December 2015, who had clinical T1-T2 and N0 disease, and who underwent either SLND (with or without subsequent ALND) or ALND were included. Differences in utilization across race, ethnicity, insurance type, facility, and residential characteristics were assessed using multivariable logistic regression.

RESULTS

Overall, 271,689 patients were included, of which 26,527 (10%) received ALND and 245,162 (90%) underwent SLND. After adjusting for demographics and cancer characteristics, black (odds ratio [OR], 1.11; 95% confidence interval [95% CI], 1.06-1.17) and Hispanic women (OR, 1.16; 95% CI, 1.10-1.24) were more likely to receive ALND. Patients without health insurance (OR, 1.33; 95% CI, 1.19-1.47), compared with private health insurance, and those receiving treatment at community cancer centers (OR, 1.60; 95% CI, 1.53-1.67), compared with academic/research centers, were also more likely to receive ALND.

CONCLUSIONS

Although the vast majority of women undergo SLND, significant disparities exist in its utilization for early stage breast cancer, with traditionally underserved patients receiving unwarranted extensive axillary surgery. Increased patient and surgeon education is needed to decrease variations in care that can affect patient's quality of life.

Leptin Receptor-Deficient MMTV-TGF-α/Leprdb Leprdb Female Mice Do Not Develop Oncogene-Induced Mammary Tumors

Being overweight is a risk factor for postmenopausal breast cancer and is associated with an increased incidence and shortened latency of spontaneous and chemically Induced mammary tumors in rodents. However, leptin-deficient obese Lepob Lepob female mice have reduced incidences of spontaneous and oncogene-induced mammary tumors. Of interest, leptin enhances the proliferation of human breast cancer cell lines in which leptin receptors are expressed, which suggests that leptin signaling plays a role in tumor development. We evaluated oncogene-induced mammary tumor development in obese MMTV-TGF-α/Leprdb Leprdb mice that exhibit a defect in OB-Rb, which is considered to be the major signaling isoform of the leptin receptor. Lepr and MMTV-TGF-α mice were crossed, and the offspring were genotyped for oncogene expression and the determination of Lepr status. Lean MMTV-TGF-α/Lepr+ Lepr+ (homozygous) and MMTV-TGF-α/Lepr+ Leprdb (heterozygous) mice and obese MMTV-TGF-α/Leprdb Leprdb mice were monitored until age 104 weeks. Body weights of MMTV-TGF-α/Leprdb Leprdb mice were significantly heavier than those of the lean groups. No mammary tumors were detected in MMTV-TGF-α/LeprdbLeprdb mice, whereas the incidence of mammary tumors in MMTV-TGF-α/Lepr+ Lepr+ and MMTV-TGF-α/Lepr+ Leprdb mice was 69% and 82%, respectively. Examination of mammary tissue whole mounts indicated an absence of duct formation and branching for MMTV-TGF-α/Leprdb Leprdb mice. Both age at mammary tumor detection and tumor burden (tumors/mouse and tumor weights) were similar for the lean genotypes. Serum leptin levels of MMTV-TGF-α/Leprdb Leprdb mice were 12-20-fold higher than levels of lean mice. Thus, despite elevated serum leptin levels, leptin receptor-deficient MMTV-TGF-α/Leprdb Leprdb mice do not develop mammary tumors. This study provides additional evidence that leptin and its cognate receptor may be involved in mammary tumorigenesis.

Racial Differences in Utilization of Breast Conservation Surgery: Results from the National Cancer Data Base (NCDB)

BACKGROUND

Whether rates of breast-conservation surgery (BCS) vary based on race and ethnicity has not been clearly elucidated on a national leve.

METHODS

The National Cancer Data Base (NCDB) was used to identify women who underwent surgery for invasive breast cancer during 2010 and 2011. The effect of race and ethnicity on BCS rates was determined, independent of patient demographics, tumor-related variables, and geographic region.

RESULTS

There were 299,827 patients with known race and ethnicity who underwent definitive breast surgery. BCS rates by race were as follows: 135,065/241,236 (56.0 %) for whites, 17,819/33,301 (53.5 %) for blacks, 4,722/9,508 (49.7 %) for Asian/Pacific Islanders, and 7,919/15,782 (50.2 %) for Hispanics (p < 0.001). Mean tumor size differed among the racial groups: 2.07 cm in whites, 2.54 cm in blacks, 2.23 cm in Asians, and 2.48 cm in Hispanics (p < 0.001). When stratified by tumor size, BCS was most common in blacks and least common in Asians for all tumors >2 cm (p < 0.001). On multivariable analysis adjusted for age, tumor size, nodal status, grade, molecular type, geographic area, urban/rural residence, insurance status, and census-derived median income and education for the patient's zip code, the odds ratio for BCS for blacks compared to whites was 1.23 (95 % confidence interval [CI] 1.20-1.27, p < 0.001), for Asians was 0.84 (95 % CI 0.80-0.88, p < 0.001), and for Hispanics was 1.00 (95 % CI 0.96-1.05, p = 0.885).

CONCLUSIONS

When adjusted for patient demographics, tumor-related variables, and geographic area, BCS rates are higher in blacks and lower in Asians compared to whites.

An exercise trial targeting African-American women with metabolic syndrome and at high risk for breast cancer: Rationale, design, and methods

BACKGROUND

Metabolic syndrome and obesity are known risk factors for breast cancers. Exercise interventions can potentially modify circulating biomarkers of breast cancer risk but evidence in African-Americans and women with metabolic syndrome is lacking.

METHODS/DESIGN

The Focused Intervention on Exercise to Reduce CancEr (FIERCE) trial is a prospective, 6-month, 3-arm, randomized controlled trial to examine the effect of exercise on obesity, metabolic syndrome components, and breast cancer biomarkers among African-American women at high risk of breast cancer. Two hundred-forty inactive women with metabolic syndrome and absolute risk of breast cancer ≥ 1.40 will be randomized to one of the three trial arms: 1) a supervised, facility-based exercise arm; 2) a home-based exercise arm; and 3) a control group that maintains physical activity levels through the course of the trial. Assessments will be conducted at baseline, 3 months, and 6 months. The primary outcome variables are anthropometric indicators of obesity, metabolic syndrome components, and inflammatory, insulin-pathway, and hormonal biomarkers of breast cancer risk.

DISCUSSION

The FIERCE trial will provide evidence on whether a short-term exercise intervention might be effective in reducing breast cancer risk among African-American women with comorbidities and high breast cancer risk--a group traditionally under-represented in non-therapeutic breast cancer trials.

CLINICAL TRIAL REGISTRATION NUMBER

NCT02103140.

Collaborative modeling of the impact of obesity on race-specific breast cancer incidence and mortality

Obesity affects multiple points along the breast cancer control continuum from prevention to screening and treatment, often in opposing directions. Obesity is also more prevalent in Blacks than Whites at most ages so it might contribute to observed racial disparities in mortality. We use two established simulation models from the Cancer Intervention and Surveillance Modeling Network (CISNET) to evaluate the impact of obesity on race-specific breast cancer outcomes. The models use common national data to inform parameters for the multiple US birth cohorts of Black and White women, including age- and race-specific incidence, competing mortality, mammography characteristics, and treatment effectiveness. Parameters are modified by obesity (BMI of ≥ 30 kg/m(2)) in conjunction with its age-, race-, cohort- and time-period-specific prevalence. We measure age-standardized breast cancer incidence and mortality and cases and deaths attributable to obesity. Obesity is more prevalent among Blacks than Whites until age 74; after age 74 it is more prevalent in Whites. The models estimate that the fraction of the US breast cancer cases attributable to obesity is 3.9-4.5 % (range across models) for Whites and 2.5-3.6 % for Blacks. Given the protective effects of obesity on risk among women <50 years, elimination of obesity in this age group could increase cases for both the races, but decrease cases for women ≥ 50 years. Overall, obesity accounts for 4.4-9.2 % and 3.1-8.4 % of the total number of breast cancer deaths in Whites and Blacks, respectively, across models. However, variations in obesity prevalence have no net effect on race disparities in breast cancer mortality because of the opposing effects of age on risk and patterns of age- and race-specific prevalence. Despite its modest impact on breast cancer control and race disparities, obesity remains one of the few known modifiable risks for cancer and other diseases, underlining its relevance as a public health target.

Differences in treatment and survival among African-American and Caucasian women with early stage operable breast cancer

OBJECTIVE

To examine racial disparities associated with breast cancer treatment and survival in elderly patients with early stage operable breast cancer.

METHODS

We studied 23,110 women with node-positive and 31,572 women with node-negative tumor who were aged ≥65 with stages I, II, or IIIA breast cancer in 1991-2002 using the Surveillance, Epidemiology and End Results (SEER)-Medicare linked data. Logistic regression analyses were performed to assess the odds of receiving adjuvant chemotherapy and radiation after breast conserving surgery (BCS) for blacks compared to whites. Cox proportional hazard regression models were used to determine the risk of mortality in blacks compared to whites, stratified by types of treatment.

RESULTS

Black women with node-positive and node-negative tumors were 25% (odds ratio = 0.75, 95% CI = 0.65-0.87) and 17% (0.83, 0.70-0.99) less likely to receive chemotherapy than white women, after adjusting for patient and tumor characteristics. This relation was not attenuated and remained statistically significant even after adjustment for socioeconomic status. In women with node-negative tumor who did not receive chemotherapy, black women were significantly more likely to die than white women (hazard ratio (HR) = 1.14, 95% CI = 1.04-1.24) after adjusting for patient and tumor characteristics, and comorbidity; and (1.11, 1.01-1.22) after additionally adjusting for socioeconomic status.

CONCLUSIONS

There were racial disparities between black and white women in receiving adjuvant chemotherapy and radiotherapy following BCS. Higher risk of mortality in black compared to white women was found only in those receiving no chemotherapy. Future studies should explore the root causes of racial disparities beyond treatment factors.

Paracrine-acting adiponectin promotes mammary epithelial differentiation and synergizes with genistein to enhance transcriptional response to estrogen receptor β signaling

Mammary stromal adipocytes constitute an active site for the synthesis of the adipokine, adiponectin (APN) that may influence the mammary epithelial microenvironment. The relationship between "local," mammary tissue-derived APN and breast cancer risk is poorly understood. Here, we identify a novel mechanism of APN-mediated signaling that influences mammary epithelial cell proliferation, differentiation, and apoptosis to modify breast cancer risk. We demonstrate that early dietary exposure to soy protein isolate induced mammary tissue APN production without corresponding effects on systemic APN levels. In estrogen receptor (ER)-negative MCF-10A cells, recombinant APN promoted lobuloalveolar differentiation by inhibiting oncogenic signal transducer and activator of transcription 3 activity. In ER-positive HC11 cells, recombinant APN increased ERβ expression, inhibited cell proliferation, and induced apoptosis. Using the estrogen-responsive 4X-estrogen response element promoter-reporter construct to assess ER transactivation and small interfering RNA targeting of ERα and ERβ, we show that APN synergized with the soy phytoestrogen genistein to promote ERβ signaling in the presence of estrogen (17β-estradiol) and ERβ-specific agonist 2,3-bis(4-hydroxyphenyl)-propionitrile and to oppose ERα signaling in the presence of the ERα-specific agonist 4,4',4'-(4-propyl-(1H)-pyrazole-1,3,5-triyl)trisphenol. The enhancement of ERβ signaling with APN + genistein cotreatments was associated with induction of apoptosis, increased expression of proapoptotic/prodifferentiation genes (Bad, p53, and Pten), and decreased antiapoptotic (Bcl2 and survivin) transcript levels. Our results suggest that mammary-derived APN can influence adjacent epithelial function by ER-dependent and ER-independent mechanisms that are consistent with reduction of breast cancer risk and suggest local APN induction by dietary factors as a targeted approach for promotion of breast health.

A review of body size and breast cancer risk in Hispanic and African American women

Obesity is an epidemic in the United States, especially among Hispanics and African Americans. Studies of obesity and breast cancer risk have been conducted primarily in non-Hispanic whites. There have been few studies of the association between body mass index (BMI) or weight gain and the risk of breast cancer in minorities, and the results have been inconsistent. Because most studies are conducted primarily in non-Hispanic whites, the etiology of breast cancer in minorities is not well understood. The authors of the current report reviewed the literature on the association between obesity, weight, and weight gain and breast cancer in minorities using a combination of the Medical Subject Heading (MeSH) terms "obesity," "body mass index," "weight," "weight gain," "Hispanic," and "African American." Only publications in English and with both risk estimates and 95% confidence intervals were considered. Forty-five studies of body size and breast cancer risk in non-Hispanic whites were identified. After an exhaustive search of the literature, only 3 studies of body size and breast cancer were conducted in Hispanic women were identified, and only 8 such studies in African American women were identified. The results were inconsistent in both race/ethnicity groups, with studies reporting positive, inverse, and null results. Thus, as obesity rates among Hispanics and African Americans continue to rise, there is an urgent need to identify the roles that both obesity and adult weight gain play in the development of breast cancer in these minorities. Additional studies are needed to provide more understanding of the etiology of this disease and to explain some of the disparities in incidence and mortality.

The association of body mass index with mortality in the California Teachers Study

Although underweight and obesity have been associated with increased risk of mortality, it remains unclear whether the associations differ by hormone therapy (HT) use and smoking. The authors examined the relationship between body mass index (BMI) and mortality within the California Teachers Study (CTS), specifically considering the impact of HT and smoking. The authors examined the associations of underweight and obesity with risks of all-cause and cause-specific mortality, among 115,433 women participating in the CTS, and specifically examined whether HT use or smoking modifies the effects of obesity. Multivariable Cox proportional hazards regression provided estimates of relative risks (RRs) and 95% confidence intervals (CIs). During follow up, 10,574 deaths occurred. All-cause mortality was increased for underweight (BMI <18.5; adjusted RR = 1.33, 95% CI = 1.20-1.47) and obese participants (BMI ≥ 30: RR = 1.27, 95% CI = 1.19-1.37) relative to BMI of 18.5-24.9). Respiratory disease mortality was increased for underweight and obese participants. Death from any cancer, and breast cancer specifically, and cardiovascular disease was observed only for obese participants. The obesity and mortality association remained after stratification on HT and smoking. Obese participants remained at greater risk for mortality after stratification on menopausal HT and smoking. Obesity was associated with increased all-cause mortality, as well as death from any cancer (including breast), and cardiovascular and respiratory diseases. These findings help to identify groups at risk for BMI-related poor health outcomes.

Obesity and breast cancer: status of leptin and adiponectin in pathological processes

It is well recognized that obesity increases the risk of various cancers, including breast malignancies in postmenopausal women. Furthermore, obesity may adversely affect tumor progression, metastasis, and overall prognosis in both pre- and postmenopausal women with breast cancer. However, the precise mechanism(s) through which obesity acts is/are still elusive and this relationship has been the subject of much investigation and speculation. Recently, adipose tissue and its associated cytokine-like proteins, adipokines, particularly leptin and adiponectin, have been investigated as mediators for the association of obesity with breast cancer. Higher circulating levels of leptin found in obese subjects could be a growth-enhancing factor as supported by in vitro and preclinical studies, whereas low adiponectin levels in obese women may be permissive for leptin's growth-promoting effects. These speculations are supported by in vitro studies which indicate that leptin promotes human breast cancer cell proliferation while adiponectin exhibits anti-proliferative actions. Further, estrogen and its receptors have a definite impact on the response of human breast cancer cell lines to leptin and adiponectin. More in-depth studies are needed to provide additional and precise links between the in vivo development of breast cancer and the balance of adiponectin and leptin.

Healthcare access, socioeconomic factors and late-stage cancer diagnosis: an exploratory spatial analysis and public policy implication

Patients diagnosed with late-stage cancer have lower survival rates than those with early-stage cancer. This paper examines possible associations between several risk factors and late-stage diagnosis for four types of cancer in Illinois: breast cancer, prostate cancer, colorectal cancer, and lung cancer. Potential risk factors are composed of spatial factors and nonspatial factors. The spatial factors include accessibility to primary healthcare and distance or travel time to the nearest cancer screening facility. A set of demographic and socioeconomic variables are consolidated into three nonspatial factors by factor analysis. The Bayesian model with convolution priors is utilised to analyse the relationship between the above risk factors and each type of late-stage cancer while controlling for spatial autocorrelation. The results for breast cancer suggest that people living in neighbourhoods with socioeconomic disadvantages and cultural barriers are more likely to be diagnosed at a late stage. In regard to prostate cancer, people in regions with low socioeconomic status are also more likely to be diagnosed at a late stage. Diagnosis of late-stage colorectal or lung cancer is not significantly associated with any of the abovementioned risk factors. The results have important implications in public policy.

Impact of obesity on diagnosis and treatment of breast cancer

In this population-based study, we evaluated the impact of obesity on presentation, diagnosis and treatment of breast cancer. Among all women diagnosed with invasive breast cancer in the canton Geneva (Switzerland) between 2003 and 2005, we identified those with information on body mass index (BMI) and categorized them into normal/underweight (BMI <25 kg/m(2)), overweight (BMI > or =-<30 kg/m(2)) and obese (BMI > or =30 kg/m(2)) women. Using multivariate logistic regression, we compared tumour, diagnosis and treatment characteristics between groups. Obese women presented significantly more often with stage III-IV disease (adjusted odds ratio [OR(adj)]: 1.8, 95% CI: 1.0-3.3). Tumours > or =1 cm and pN2-N3 lymph nodes were significantly more often impalpable in obese than in normal/underweight patients (OR(adj) 2.4, [1.1-5.3] and OR(adj) 5.1, [1.0-25.4], respectively). Obese women were less likely to have undergone ultrasound (OR(adj) 0.5, [0.3-0.9]) and MRI (OR(adj) 0.3, [0.1-0.6]) and were at increased risk of prolonged hospital stay (OR(adj) 4.7, [2.0-10.9]). This study finds important diagnostic and therapeutic differences between obese and lean women, which may impair survival of obese women with breast cancer. Specific strategies are needed to optimize the care of obese women with or at risk of breast cancer.

Obesity and mammography: a systematic review and meta-analysis

BACKGROUND

Obese women experience higher postmenopausal breast cancer risk, morbidity, and mortality and may be less likely to undergo mammography.

OBJECTIVES

To quantify the relationship between body weight and mammography in white and black women.

DATA SOURCES AND REVIEW METHODS

We identified original articles evaluating the relationship between weight and mammography in the United States through electronic and manual searching using terms for breast cancer screening, breast cancer, and body weight. We excluded studies in special populations (e.g., HIV-positive patients) or not written in English. Citations and abstracts were reviewed independently. We abstracted data sequentially and quality information independently.

RESULTS

Of 5,047 citations, we included 17 studies in our systematic review. Sixteen studies used self-reported body mass index (BMI) and excluded women <40 years of age. Using random-effects models for the six nationally representative studies using standard BMI categories, the combined odds ratios (95% CI) for mammography in the past 2 years were 1.01 (0.95 to 1.08), 0.93 (0.83 to 1.05), 0.90 (0.78 to 1.04), and 0.79 (0.68 to 0.92) for overweight (25-29.9 kg/m(2)), class I (30-34.9 kg/m(2)), class II (35-39.9 kg/m(2)), and class III (> or =40 kg/m(2)) obese women, respectively, compared to normal-weight women. Results were consistent when all available studies were included. The inverse association was found in white, but not black, women in the three studies with results stratified by race.

CONCLUSIONS

Morbidly obese women are significantly less likely to report recent mammography. This relationship appears stronger in white women. Lower screening rates may partly explain the higher breast cancer mortality in morbidly obese women.

Triple-negative breast cancer and obesity in a rural Appalachian population

BACKGROUND

Our objective was to determine the clinicopathologic features of triple-negative (estrogen receptor, progesterone receptor, and human epidermal growth factor-2 receptor negative) breast cancer and their relationship to obesity in women drawn from a population with one of the highest obesity rates in the United States.

METHODS

This retrospective study involved 620 White patients with invasive breast cancer in West Virginia. Hospital tumor registry, charts, and pathology records provided age at diagnosis, tumor histologic type, size, nodal status, and receptor status. Body mass index was calculated and a value of > or = 30 was considered indicative of obesity.

RESULTS

Triple-negative tumors occurred in 117 (18.9%) of the 620 patients, most often in association with invasive ductal carcinomas. Patients with triple-negative tumors were younger than those with other receptor types, 44.5% and 26.7%, respectively, being diagnosed at age <50 years (P = 0.0004). The triple-negative tumors were larger (P = 0.0003), most notably in the younger women, but small tumors (<2.0 cm) were more often accompanied by lymph node metastases. Obesity was present in 49.6% of those with triple-negative tumors but in only 35.8% of those with non-triple-negative tumors (P = 0.0098). Lymph node metastases were more frequently associated with T(2) tumors in obese patients (P = 0.032) regardless of their receptor status.

CONCLUSIONS

Triple-negative breast cancers within a White, socioeconomically deprived, population occurred in younger women, with later stage at diagnosis, and in association with obesity, which itself has been associated with a poor prognosis in breast cancer.

An online forum exploring needs for help of patients with cancer: gender and ethnic differences

PURPOSE/OBJECTIVES

To explore gender and ethnic differences in needs for help among patients with cancer.

RESEARCH APPROACH

Qualitative.

SETTING

Internet and community settings.

PARTICIPANTS

16 self-identified patients with cancer aged at least 18 years who could read and write English.

METHODOLOGIC APPROACH

Using six discussion topics on needs for help, an online forum was administered for one month. Data were analyzed with thematic analysis.

MAIN RESEARCH VARIABLES

Need for help.

FINDINGS

Four major themes emerged: (a) from side effects to racism, (b) same or double stress, (c) cultural hesitance and God, and (d) a family disease with mistrust. Depending on gender and ethnicity, the participants' concerns were various and ranged from a simple physical need to a social need for elimination of racism in United States society. Women tended to report double burden and stress as patients with cancer resulting from their gender. Ethnic minorities tended to be hesitant to talk about cancer or seek help because of the stigmatized nature of cancer. Ethnic minority patients perceived cancer as a family disease that they needed to go through as a family, and they tended to mistrust healthcare providers.

CONCLUSIONS

The overriding theme was a marginalized experience for ethnic minority patients with cancer.

INTERPRETATION

Researchers should include cultural needs as a separate category of needs and consider contextual factors influencing the needs of patients with cancer in their daily lives.

Experiences with weight change in African-American breast cancer survivors

Although weight gain is a common side effect of breast cancer treatment, limited empirical data are available on how African-American breast cancer survivors react to changes in their weight following diagnosis and treatment. The purpose of this study was to explore psychological and behavioral reactions to weight change in African-American breast cancer survivors. We conducted a qualitative study to explore reactions to weight change following diagnosis and treatment in 34 African-American breast cancer survivors. Forty-seven percent of women reported gaining weight, 32% reported weight loss, and 21% reported no changes in their weight. Regardless of whether women gained or lost weight, these changes were viewed as stressors that caused psychological distress and health concerns. However, some women had positive reactions to weight loss, especially if they had been heavy prior to diagnosis. Women exercised and changed their dietary behaviors following treatment. Despite this, women reported being frustrated with not being able to control changes in their weight. These results suggest that changes in weight may be a critical component of breast cancer survivorship in African-American women. It may be important to provide African-American breast cancer survivors with information about the causes and implications of weight change and strategies for weight control after treatment as part of their follow-up care.

Adiposity, the metabolic syndrome, and breast cancer in African-American and white American women

Breast cancer, the second most common cause of cancer-related deaths in American women, varies substantially in incidence and mortality according to race and ethnicity in the United States. Although the overall incidence of breast cancer among African-American (AA) women is lower than in white American women, this cancer is more common in young premenopausal AA women, and AA breast cancer patients of all ages are more likely to have advanced disease at diagnosis, higher risk of recurrence, and poorer overall prognosis. Epidemiological studies indicate that these differences may be attributable in part to variation in obesity and body fat distribution. Additionally, AA women more frequently exhibit breast cancer with an aggressive and metastatic phenotype that may also be attributable to the endocrine and metabolic changes associated with upper body obesity. These changes include both elevated estrogen and androgen bioactivity, hyperinsulinemia, and perturbations of the adipokines. Type 2 diabetes and the metabolic syndrome, which are more common in AA women, have also been associated with breast cancer risk. Moreover, each of the individual components of the syndrome has been associated with increased breast cancer risk, including low levels of the adipocytokine, adiponectin. This review explores the specific roles of obesity, body fat distribution (particularly visceral and sc adipose tissue), type 2 diabetes, metabolic syndrome, and adipocytokines in explaining the differential patterns of breast cancer risk and prognosis between AA and white American women.

Combination of physical activity, nutrition, or other metabolic factors and vaccine response

A number of lifestyle factors that reduce cancer risk in the primary prevention setting may be potential new targets for use in combination with cancer vaccines. This review discusses the modulation of energy balance (physical activity, calorie restriction, and obesity prevention), and the supplementation with natural and synthetic analogs of vitamins A and E, as potential interventions for use in combination with cancer vaccines. Additionally, the pharmacologic manipulation of nutrient metabolism in the tumor microenvironment (e.g., arachidonic acid, arginine, tryptophan, and glucose metabolism) is discussed. This review includes a brief overview of the role of each agent in primary cancer prevention; outlines the effects of these agents on immune function, specifically adaptive and/or anti-tumor immune mechanisms, when known; and discusses the potential use of these interventions in combination with therapeutic cancer vaccines. Modulation of energy balance through exercise and strategies targeting nutrient metabolism in the tumor microenvironment represent the most promising interventions to partner with therapeutic cancer vaccines. Additionally, the use of vitamin E succinate and the retinoid X receptor-directed rexinoids in combination with cancer vaccines offer promise. In summary, a number of energy balance- and nutrition-related interventions are viable candidates for further study in combination with cancer vaccines.

Cancer screening in women: body mass index and adherence to physician recommendations

BACKGROUND

The reasons that obese women are less likely to obtain mammograms and Papanicolaou tests (Pap smears) are poorly understood. This study evaluated associations between body mass index (BMI) and receipt of and adherence to physician recommendations for mammography and Pap smear.

METHODS

Data from the 2000 National Health Interview Survey (8289 women aged 40 to 74 years) were analyzed in 2006 using logistic regression. Women with previous hysterectomy were excluded from Pap smear analyses (n=5521). Outcome measures were being up-to-date with screening, receipt of physician recommendations, and women's adherence to physician recommendations for mammography and Pap smear.

RESULTS

After adjusting for sociodemographic variables, healthcare access, health behaviors, and comorbidity, severely obese women (BMI > 40 kg/m(2)) were less likely to have had mammography within 2 years (odds ratio [OR]=0.50, 95% confidence interval [CI]=0.37-0.68) and a Pap smear within 3 years (OR=0.43, 95% CI=0.27-0.70). Obese women were as likely as normal-weight women to receive physician recommendations for mammography and Pap smear. Severely obese women were less likely to adhere to physician recommendations for mammography (OR=0.49, 95% CI=0.32-0.76). Women in all obese categories (BMI > 30 kg/m(2)) were less likely to adhere to physician recommendations for Pap smear (ORs ranged from 0.17 to 0.28, p<0.001).

CONCLUSIONS

Obese women are less likely to adhere to physician recommendations for breast and cervical cancer screening. Interventions focusing solely on increasing physician recommendations for mammography and Pap smears will probably be insufficient for obese women. Additional strategies are needed to make cancer screening more acceptable for this high-risk group.

Body Mass Index Influences Palpability but not Stage of Breast Cancer at Diagnosis

Body mass index (BMI) is associated with breast cancer risk, but its relationship with stage at diagnosis is unclear. BMI was calculated for patients in the North American Fareston and Tamoxifen Adjuvant trial, and was correlated with clinicopathologic factors, including stage at diagnosis. One thousand eight hundred fourteen patients were enrolled in the North American Fareston and Tamoxifen Adjuvant study; height and weight were recorded in 1451 (80%) of them. The median BMI was 27.1 kg/m2 (range, 14.7–60.7). The median patient age was 68 years (range, 42–100); median tumor size was 1.3 cm (range, 0.1–14 cm). One thousand seven hundred ninety-three (99.0%) patients were estrogen receptor positive, and 1519 (84.7%) were progesterone receptor positive. There was no significant relationship between BMI (as a continuous variable) and nodal status ( P = 0.469), tumor size ( P = 0.497), American Joint Committee on Cancer stage ( P = 0.167), grade ( P = 0.675), histologic subtype ( P = 0.179), or estrogen receptor status ( P = 0.962). Patients with palpable tumors, however, had a lower BMI than those with nonpalpable tumors (median 26.4 kg/m2 vs 27.5 kg/m2, P < 0.001). Similar results were found when BMI was classified as a categorical variable (<25 vs 25–29.9 vs ≥30). Increased BMI does not lead to a worse stage at presentation. Obese patients, however, tend to have nonpalpable tumors. Mammography in this population is especially important.

Breast and cervical cancer screening in obese minority women

PURPOSE

Studies using survey data from mostly white women showed that obese women are less likely than nonobese women to undergo breast and cervical cancer screening. It is unclear if these findings are true in nonwhite women. Using chart audit data, we examined the relationship between obesity and mammography and Pap smear screening among minority women.

METHODS

Data from retrospective chart review of women in three urban New Jersey academic family medicine practices were analyzed (n = 1809) using hierarchical logistic regression models. Outcome measures were being up-to-date in mammography and Pap smears among obese and nonobese women.

RESULTS

There was no difference in mammography rates among obese and nonobese women. Independent risk factors for not being up-to-date in mammography included age 40-49, smoking, and comorbidity. Obese women were less likely than nonobese women to be upto- date in Pap smears (69% vs. 77%, p = 0.001). In multivariate analysis, obesity was associated with 25% decreased odds of being up-to-date on Pap smears (OR, 0.75, 95% CI, 0.58-0.99, p = 0.041). Age >or=65 years was also associated with decreased odds of being up-to-date in Pap smears. Hispanic women had increased odds of being up-to-date in mammography (OR 2.43, 95% CI 1.63-3.63) and Pap smears (OR 1.94, 95% CI 1.24-3.03) compared with white women.

CONCLUSIONS

Obesity was associated with decreased Pap smear screening but not with decreased mammography. Further studies are needed to determine barriers and effective interventions to improve screening in obese minority women.

Obesity and prognosis of breast cancer

Obesity has a complicated relationship to both breast cancer risk and the clinical behaviour of the established disease. It is suggested that obesity is associated with both an increased risk of developing breast cancer risk and worse prognosis after disease onset. In post-menopausal women, various measures of obesity such as body mass index, weight, weight gain and waist : hip ratio have all been positively associated with risk of developing breast cancer. In most but not all case-control and prospective cohort studies, an inverse relationship has been found between weight and breast cancer among pre-menopausal women. Some data suggest that adult weight gain and central obesity increase the risk of pre-menopausal breast cancer. Obesity at the time of diagnosis is thought to be significant as a poor prognostic factor. Obesity is associated with adverse outcomes in both pre- and post-menopausal women with breast cancer. Many cancer survivors seek ways to minimize the risk of recurrence and death because of breast cancer. Despite complex and at times controversial data, enough evidence is available at present to suggest that weight management should be a part of the strategy to prevent the occurrence, recurrence and death because of breast cancer. In this review the effect of obesity on the prognosis of breast cancer is examined in detail.

Angiogenic factors are elevated in overweight and obese individuals

BACKGROUND

Adipose tissue produces both vascular growth factors and inhibitors. Since obesity is associated with expansion of the capillary bed in regional adipose depots the balance between these factors may favor angiogenesis.

OBJECTIVE

To investigate the relationship between body mass index and serum concentrations of vascular growth factors in human subjects.

METHODS

Vascular endothelial growth factor (VEGF), VEGF-C, VEGF-D, soluble VEGF receptor-2 (sVEGFr2), hepatocyte growth factor (HGF), angiopoietin-2, angiogenin and endostatin concentrations were measured in serum collected from 58 lean (24 males, 34 female, mean BMI, 22.2+/-0.3) and 42 overweight and obese (16 males and 26 females, mean BMI, 33.5+/-1.2) subjects after an overnight fast.

RESULTS

Sexual dimorphism was apparent in the serum concentrations of VEGF-C, VEFG-D and angiopoietin-2 with significantly higher levels in female compared to male subject. VEGF, VEGF-C, VEGF-D, soluble VEGF receptor-2, angiopoietin-2, angiogenin and endostatin but not HGF were significantly elevated in overweight and obese subjects. Positive correlations between BMI and the serum concentrations of VEGF-C, VEGF-D, sVEGF-R2, angiopoietin-2, angiogenin and endostatin were observed even after adjustment for gender and age.

CONCLUSIONS

Increased levels of vascular growth factors as well as the angiogenesis inhibitor endostatin are present in overweight and obese subjects and may contribute to previously documented increased risk of metastatic disease in obese subjects with cancer.

Body mass index and breast cancer risk in African American women

PURPOSE

Studies of the relationship between body mass index (BMI) and breast cancer in African American women have been few. We conducted a case-control study to examine whether BMI is associated with risk of breast cancer in this population.

METHODS

Cases were 304 women diagnosed with breast cancer at the ages of 20 to 64 years. Controls were 305 women without a history of breast cancer. Telephone interviews were conducted to collect data on history of exposure to various factors at or before the date of diagnosis in cases or equivalent date in controls (reference date). Using logistic regression, we compared cases and controls in BMI at age 18, BMI at the reference date, and change in BMI between the two dates.

RESULTS

Using BMI at reference date, we found an odds ratio (OR) of 1.75 (95% confidence interval [CI], 1.02-3.02) and 2.32 (95% CI, 1.33-4.03) for women with BMI of 25 to 29.9 and 30 or higher, respectively, compared with women having BMI lower than 25. The corresponding OR estimates for BMI at age 18 were not significantly different from the unity. The average annual change in BMI between age 18 and date of diagnosis or reference date was associated with breast cancer risk, as shown that more BMI change tended to increase breast cancer risk compared with the baseline quartile of change. When data were analyzed by menopausal status, the association was found for both post-menopausal and pre-menopausal tumors for BMI at reference date but not for BMI at age 18. There was a higher risk for more annual BMI change compared with the baseline for both pre-menopausal and post-menopausal women.

CONCLUSION

Our results suggest that BMI at reference date and change in BMI were associated with increased risk of breast cancer in African American women, and the association might be found for both post-menopausal and pre-menopausal tumors.

Obesity and awareness of obesity as risk factors for breast cancer in six ethnic groups

OBJECTIVE

To document BMI and knowledge regarding obesity as a risk factor for breast cancer among subpopulations of African-, Caribbean-, and European-American women and to consider the variables predicting obesity in these diverse groups.

RESEARCH METHODS AND PROCEDURES

A stratified cluster-sampling plan was used to recruit 1364 older women from Brooklyn, NY, during 2000-2002. Two groups were born in the United States (African Americans and European Americans), whereas others were from the English-speaking Caribbean, Haiti, the Dominican Republic, and Eastern Europe. Participants provided demographics, height and weight measures, and estimates of the risk obesity posed for breast cancer.

RESULTS

Women from all groups were significantly overweight (BMI > 25 kg/m(2)), although European Americans were lowest, followed by Dominicans and Haitians; African-American and English-speaking Caribbean women fell into the obese range, even when background variables were controlled. Knowledge of obesity as a breast cancer risk factor was also poor across groups, but Dominicans and Haitians had the lowest scores on knowledge. Importantly, knowledge was not associated with BMI in the overall sample, even when controlling for demographics and ethnicity, although logistic regressions comparing normal weight women with overweight and obese groupings suggested some knowledge of breast cancer risk in the overweight, but not the obese, group.

DISCUSSION

The findings remind health professionals of the need to consider more specific ethnic groupings than has hitherto been the case, as well as consider how ethnic and cultural variables may influence perceptions of obesity and its relation to cancer risk.

Ethnicity and Breast Cancer: Factors Influencing Differences in Incidence and Outcome

BACKGROUND

The lower breast cancer incidence in minority women and the higher breast cancer mortality in African American women than in white women are largely unexplained. The influence of breast cancer risk factors on these differences has received little attention.

METHODS

Racial/ethnic differences in breast cancer incidence and outcome were examined in 156,570 postmenopausal women participating in the Women's Health Initiative. Detailed information on breast cancer risk factors including mammography was collected, and participants were followed prospectively for breast cancer incidence, pathological breast cancer characteristics, and breast cancer mortality. Comparisons of breast cancer incidence and mortality across racial/ethnic groups were estimated as hazard ratios (HRs) and 95% confidence intervals (CIs) from Cox proportional hazard models. Tumor characteristics were compared as odds ratios (ORs) and 95% confidence intervals in logistic regression models.

RESULTS

After median follow-up of 6.3 years, 3938 breast cancers were diagnosed. Age-adjusted incidences for all minority groups (i.e., African American, Hispanic, American Indian/Alaskan Native, and Asian/Pacific Islander) were lower than for white women, but adjustment for breast cancer risk factors accounted for the differences for all but African Americans (HR = 0.75, 95% CI = 0.61 to 0.92) corresponding to 29 cases and 44 cases per 10,000 person years for African American and white women, respectively. Breast cancers in African American women had unfavorable characteristics; 32% of those in African Americans but only 10% in whites were both high grade and estrogen receptor negative (adjusted OR = 4.70, 95% CI = 3.12 to 7.09). Moreover, after adjustment for prognostic factors, African American women had higher mortality after breast cancer than white women (HR = 1.79, 95% CI = 1.05 to 3.05) corresponding to nine and six deaths per 10 000 person-years from diagnosis in African American and white women, respectively.

CONCLUSION

Differences in breast cancer incidence rates between most racial/ethnic groups were largely explained by risk factor distribution except in African Americans. However, breast cancers in African American women more commonly had characteristics of poor prognosis, which may contribute to their increased mortality after diagnosis.

Weight, weight gain, and survival after breast cancer diagnosis

PURPOSE

To determine whether weight prior to diagnosis and weight gain after diagnosis are predictive of breast cancer survival.

METHODS

Patients included 5,204 Nurses' Health Study participants diagnosed with incident, invasive, nonmetastatic breast cancer between 1976 and 2000; 860 total deaths, 533 breast cancer deaths, and 681 recurrences (defined as secondary lung, brain, bone, or liver cancer, and death from breast cancer) accrued to 2002. We computed the change in body mass index (BMI) from before to the first BMI reported > or = 12 months after the date of diagnosis. Cox proportional hazards models were used to evaluate associations of categories of BMI before diagnosis and of BMI change with time to event. We stratified by smoking, menopausal status, and breast cancer-related variables.

RESULTS

In multivariate-adjusted analyses, weight before diagnosis was positively associated with breast cancer recurrence and death, but this was apparent only in never smokers. Similarly, among never-smoking women, those who gained between 0.5 and 2.0 kg/m(2) (median gain, 6.0 lb; relative risk [RR], 1.35; 95% CI, 0.93 to 1.95) or more than 2.0 kg/m(2) (median gain, 17.0 lb; RR, 1.64; 95% CI, 1.07 to 2.51) after diagnosis had an elevated risk of breast cancer death during follow-up (median, 9 years), compared with women who maintained their weight (test for linear trend, P = .03). Associations with weight were stronger in premenopausal than in postmenopausal women. Similar findings were noted for breast cancer recurrence and all-cause mortality.

CONCLUSION

Weight and weight gain were related to higher rates of breast cancer recurrence and mortality, but associations were most apparent in never-smoking women.

The race gap in support group participation by breast cancer survivors: real or artifact?

Addressing methodological weaknesses of previous research, this study assesses whether African American women are, in fact, less likely to participate in breast cancer support groups than are White women. Of the breast cancer survivors, 958 (26% African Americans, 73% Caucasian) completed interviews concerning demographic characteristics, other support networks, effects of illness on home and spiritual life, and support group participation. Contrary to previous research, no race difference was found in support group participation. This research suggests more effort needs to be paid to sampling techniques and other methodological factors to adequately reflect the experiences and needs of breast cancer survivors, specifically African American women.