Better breast cancer survival for postmenopausal women who are less overweight and eat less fat. The Iowa Women's Health Study

The NF-kappaB/IkappaB signaling system: a molecular target in breast cancer therapy

The nuclear factor kappaB (NFkappaB) superfamily of eukaryotic transcription factors plays an important role in carcinogenesis. NF-kappaB and its regulators are linked to various signal transduction pathways as well as transcriptional activation events that mediate critical stages of cell proliferation. These intracellular signaling processes are thought to regulate chromatin structure to accommodate transcription, apoptosis, cell-cycle control, and cell transformation. In this capacity, uncontrolled or aberrant NF-kappaB activity may, in part, be responsible for breast cancer progression. Constitutive NF-kappaB expression may predict the metastatic potential of breast tumors, indicating early use of adjuvant therapy and suggesting NF-kappaB inhibition as a novel treatment. In this review, we discuss the regulatory mechanisms and physiological significance of NF-kappaB activation, and highlight recent advances in the development of NF-kappaB as an integral mediator of mammary carcinogenesis.

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.

Role of vitamins in the risk, prevention, and treatment of breast cancer

PURPOSE OF REVIEW

This article presents an overview of the role of vitamins in the risk, prevention, and treatment of breast cancer, with emphasis on current evidence from English-language articles published since 1 August 2002 and indexed in MEDLINE.

RECENT FINDINGS

Findings from epidemiologic studies that have evaluated vitamin A and carotenoids in relation to breast cancer risk have been inconclusive. The available data, especially from prospective studies, do not support an association between vitamins E and C and risk of breast cancer. Recent studies suggest that folate plays an important role in the prevention of breast cancer, particularly among women consuming alcohol. Limited data also support a potential role of vitamin D in the prevention of breast cancer.

SUMMARY

High intake of folate or adequate circulating levels of folate may reduce the risk of breast cancer. Adequate folate levels may be particularly important for women who are at higher risk of breast cancer because of high alcohol consumption. The inverse association between vitamin D and risk of breast cancer needs to be evaluated in more studies.

Obesity and breast cancer: a review of the literature

A woman's build, the risk of breast cancer and its subsequent prognosis seem to be related. In most but not all case-control and prospective cohort studies, an inverse relationship has been found between weight and breast cancer among premenopausal women. However, most large epidemiological studies have found that overweight or obese women are at increased risk of developing postmenopausal breast cancer. It is suggested that higher body mass index is associated with a more advanced stage of breast cancer at diagnosis in terms of tumour size but data on lymph node status is not so consistent. All treatment modalities for breast cancer such as surgery, radiotherapy, chemotherapy and hormonal treatment may be adversely affected by the presence of obesity. The overall and disease-free survival is worse in most but not all studies of prognosis of obese pre- and postmenopausal women with breast cancer.

Hormonal Factors and Breast Tumor Proliferation: Do Factors that Affect Cancer Risk also Affect Tumor Growth?

BACKGROUND

Tumor cell proliferation is one of the most significant predictors of prognosis for women with breast cancer. Personal characteristics that affect hormonal exposure have been implicated in breast tumor etiology, and it is possible that they may also influence tumor cell proliferation. We examined the association between hormone-related breast cancer risk factors and breast tumor proliferation, as reflected in two proliferation measures, Ki-67 and mitotic count.

METHODS

The study population was 484 women 40 years of age and older, who were members of a managed care organization's breast cancer screening program and were diagnosed with invasive breast cancer between 1988 and 1995. The percent of Ki-67 positive tumor cells averaged over four high powered fields (Ki-67) was log transformed and analyzed in a linear regression model. Mitotic count was dichotomized into high versus low (<or=10), and analyzed in an unconditional logistic regression model with the odds ratio (OR) as the measure of association.

RESULTS

Consistent with other studies, there was a significant trend of decreased tumor cell proliferation with increasing age ( p for trend <0.05 for both measures). Higher body weight was associated with higher Ki-67 ( p for trend <0.05), but not with higher mitotic count. We found no significant associations between any reproductive factors (age at menarche, parity, age at first birth, menopausal status and age at menopause) and either measure of tumor cell proliferation. We observed an association between reduced tumor proliferation, as measured by mitotic count and former/current use of hormone replacement therapy (HRT) in comparison to never use (adjusted OR's: former HRT use: 0.40 (95% CI 0.19-0.85); current HRT use: 0.52 (95% CI 0.26-1.04).

CONCLUSION

Certain factors related to hormonal exposure that influence breast tumor etiology, for example, age, also appear to increase tumor growth. Conversely HRT use, which clearly increases breast cancer risk, may not adversely affect, and possibly may diminish cell proliferation once tumors are established.

Does obesity compromise survival in women with breast cancer?

Obesity, measured by high body mass index (BMI >30 kg/m2) is associated with an increased risk of postmenopausal breast cancer but the effect of obesity on prognosis is not clear. A prospectively accrued and regularly validated database of 1579 patients with breast cancer treated in a district general hospital between 1963 and 1999 was analysed for clinical and pathological tumour characteristics including the family history, grade, tumour type, treatment and outcome. The risk factors and outcome of obese and non-obese patients were compared. Breast cancer in obese women was associated with significantly larger tumour size and worse Nottingham prognostic index. There was no statistically significant difference in overall and disease-free survival between obese and non-obese group. Hazard ratios (95% Cl) were 0.81 (0.62-1.06) and 0.80 (0.63-1.01), respectively. In the present study, obesity is not an indicator of worst prognosis of breast cancer.

Antioxidant supplements and risk of breast cancer recurrence and breast cancer-related mortality among postmenopausal women

Despite widespread use, only a few clinical or epidemiological studies have examined the relationship between antioxidant supplements and risk of breast cancer recurrence or breast cancer-related mortality. We used proportional hazards and logistic regression modeling to estimate rate ratios and odds ratios (ORs) for recurrence and mortality among 385 postmenopausal women diagnosed with breast cancer between 1986 and 1988 enrolled into a case-control study on diet and cancer. Women were recontacted with a single questionnaire to ascertain the use of nutritional supplements during 12-14 yr of follow-up time. In multivariable models, antioxidant supplement users compared with nonusers were less likely to have a breast cancer recurrence or breast cancer-related death (OR = 0.54, 95% CI = 0.27-1.04). Vitamin E supplements showed a modest protective effect when used for more than 3 yr (OR = 0.33, 95% CI = 0.10-1.07). Premorbid dietary intake of vitamins C or E from diet, supplements, or both showed no relationship with risk. Risks of recurrence and disease-related mortality were reduced among women using vitamin C and vitamin E supplements for more than 3 yr. Recall bias among proxy respondents for women who died during follow-up may have contributed to these findings. This study provides limited support for the hypothesis that antioxidant supplements may reduce the risk of breast cancer recurrence or breast cancer-related mortality.

Telephone counseling intervention increases intakes of micronutrient- and phytochemical-rich vegetables, fruit and fiber in breast cancer survivors

Although a large body of evidence suggests that diet may play an important role in cancer prevention, randomized controlled trials reported to date have not achieved sufficient increases in protective micronutrients and phytochemicals to adequately test the hypothesis that diet can reduce cancer risk. The Women's Healthy Eating and Living (WHEL) Study, a randomized controlled trial of the role diet modification may play in future breast cancer events, introduced an innovative theory-based telephone counseling intervention to teach participants to consume a high fiber, low fat diet emphasizing vegetables and fruits rich in carotenoids and other potentially protective phytochemicals. This report examines the baseline to 12-mo changes in dietary intakes of 2970 participants, assessed through 24-h recalls and validated with plasma carotenoid concentrations. At 12 mo, the intervention group reported a significantly increased daily vegetable intake (+vegetable juice) of 7.1 servings (+82%) and fruit intake of 3.9 servings (+18%). Fiber intake increased from 3.04 to 4.16 g/(MJ. d), whereas energy from fat decreased significantly from 28.6 to 23.7%. Plasma carotenoid concentrations increased significantly, i.e., alpha-carotene (+223%); beta-carotene (+87%); lutein (+29%); and lycopene (+17%). In the comparison group, dietary intake and plasma carotenoid concentrations were essentially identical to those of the intervention group at baseline and were unchanged at 12 mo. The WHEL Study showed that a telephone counseling intervention can achieve major increases in micronutrient- and phytochemical-rich vegetables, fruit and fiber intakes, enabling an investigation of the potential cancer preventive effects of these food components.

Identification of molecular targets for dietary energy restriction prevention of skin carcinogenesis: An idea cultivated by Edward Bresnick

Dietary energy restriction (DER) has long been known to strikingly inhibit carcinogenesis in many animal models. The animal data has been corroborated by recent and ongoing epidemiological studies demonstrating the importance of energy balance, physical exercise and obesity in human cancer. Dr. Edward Bresnick provided key insights into this important area of research and pivotal direction for the author's research while he served as Director of the Eppley Institute for Research in Cancer, Omaha, NE. These insights moved this research toward demonstrating that DER reduced the expression of key protein kinase C isoforms in mouse skin. More recent studies have uncovered downstream events that are inhibited by DER including blockage of tumor promoter activation of Raf-1, ERK 1,2 and AP-1 expression. Parallel studies have demonstrated the DER inhibition of these key cellular signaling events in mouse skin carcinogenesis are dependent upon an intact adrenal gland because adrenalectomized mice fed DER diet did not have reduced tumor burden or inhibited signaling and blocked AP-1 activation as was observed in DER mice with intact adrenal glands. In addition, the DER inhibition of tumorigenesis and AP-1 signaling was restored in adrenalectomized mice that were given corticosterone in the drinking water. This showed that in mice in the chemical carcinogenesis protocol glucocorticoid hormone plays a major role in mediating DER prevention of cancer. Studies are ongoing to further assess the mechanism of DER modulation of skin cancer by assessing impacts on transcriptional regulation and expression of genes that are critical in skin carcinogenesis.

Nutrition-related issues for the breast cancer survivor

Nutritional status and dietary intake play a significant role in the prognosis of breast cancer patients and may modify the progression of disease, as well as influence risk for comorbid conditions, such as osteoporosis and cardiovascular disease. A critical review of relevant clinical and epidemiological studies identified through MEDLINE and CINAHL searches was undertaken to provide the clinician with a summary of evidence that could form the appropriate guidance of women diagnosed with breast cancer who seek to reduce their risk of progressive or recurrent disease, and improve their overall health. Currently, healthy weight control with an emphasis on exercise to preserve or increase both lean body and bone masses, and plant-based diets that include ample amounts of nutrient-dense, low-energy density foods, particularly vegetables, can be recommended. Furthermore, diets high in vegetables, fruit, whole grains, and low-fat dairy foods, and low in saturated fat, may help to lower overall disease risk in this population.

Obesity, tamoxifen use, and outcomes in women with estrogen receptor-positive early-stage breast cancer

BACKGROUND

Obesity is associated with both increased breast cancer risk and poorer prognosis after disease onset. However, little is known about the effect of obesity on treatment efficacy. We evaluated the association of obesity with outcomes and with tamoxifen efficacy in women with early-stage, hormone-responsive breast cancer participating in a multicenter cancer cooperative group clinical trial.

METHODS

The cohort consisted of 3385 women enrolled in National Surgical Adjuvant Breast and Bowel Project (NSABP) protocol B-14, a randomized, placebo-controlled trial evaluating tamoxifen for lymph node-negative, estrogen receptor (ER)-positive breast cancer. Hazards of breast cancer recurrence, contralateral breast tumors, other new primary cancers, and several mortality endpoints were evaluated in relation to body mass index (BMI), using statistical modeling to adjust for other prognostic factors. Median follow-up time was 166 months. All statistical tests were two-sided.

RESULTS

The hazard of breast cancer recurrence was the same among obese (BMI > or =30.0 kg/m2) women as compared with underweight and normal-weight women (BMI <25.0; hazard ratio [HR] = 0.98, 95% confidence interval [CI] = 0.80 to 1.18). Contralateral breast cancer hazard was higher in obese women than in underweight/normal-weight women (HR = 1.58, 95% CI = 1.10 to 2.25), as was the risk of other primary cancers (HR = 1.62, 95% CI = 1.16 to 2.24). Compared with normal-weight women, obese women had greater all-cause mortality (HR = 1.31, 95% CI = 1.12 to 1.54) and greater risk of deaths due to causes unrelated to breast cancer (HR = 1.49, 95% CI = 1.15 to 1.92). Breast cancer mortality was not statistically significantly increased for obese women (HR = 1.20, 95% CI = 0.97 to 1.49). Tamoxifen reduced breast cancer recurrence and mortality, regardless of BMI.

CONCLUSIONS

For women with lymph node-negative, ER-positive breast cancer, obesity was not associated with a material increase in recurrence risk or a change in tamoxifen efficacy. However, because obesity was associated with increased risks of contralateral breast cancer, of other primary cancers, and of overall mortality, it may influence long-term outcomes for breast cancer survivors.

Dietary influences on survival after ovarian cancer

We evaluated the effects of various food groups and micronutrients in the diet on survival among women who originally participated in a population-based case-control study of ovarian cancer conducted across 3 Australian states between 1990 and 1993. This analysis included 609 women with invasive epithelial ovarian cancer, primarily because there was negligible mortality in women with borderline tumors. The women's usual diet was assessed using a validated food frequency questionnaire. Deaths in the cohort were identified using state-based cancer registries and the Australian National Death Index (NDI). Crude 5-year survival probabilities were estimated using the Kaplan-Meier technique, and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) were obtained from Cox regression models. After adjusting for important confounding factors, a survival advantage was observed for those who reported higher intake of vegetables in general (HR = 0.75, 95% CI = 0.57-0.99, p-value trend 0.01 for the highest third, compared to the lowest third), and cruciferous vegetables in particular (HR = 0.75, 95% CI = 0.57-0.98, p-value trend 0.03), and among women in the upper third of intake of vitamin E (HR = 0.76, 95% CI = 0.58-1.01, p-value trend 0.04). Inverse associations were also seen with protein (p-value trend 0.09), red meat (p-value trend 0.06) and white meat (p-value trend 0.07), and modest positive trends (maximum 30% excess) with lactose (p-value trend 0.04), calcium and dairy products. Although much remains to be learned about the influence of nutritional factors after a diagnosis of ovarian cancer, our study suggests the possibility that a diet high in vegetable intake may help improve survival.

Survival from breast cancer among South Asian and non-South Asian women resident in South East England

Ethnic differences in breast cancer survival have been observed in the USA but have not been examined in Britain. We aimed to investigate such differences between South Asian (i.e. those with family roots in the Indian subcontinent) and non-South Asian (essentially British-native) women in England. Primary breast cancer cases incident in 1986 -1993 and resident in South East England were ascertained through the Thames Cancer and Registry and followed up to the end of 1997. Cases of South Asian ethnicity were identified on the basis of their names by using a previously validated computer algorithm. A total of 1037 South Asian and 50 201 non-South Asian breast cancer cases were included in the analysis; 30% of the South Asian (n=312) and 44% (n=22 201) of the non-South Asian cases died during follow-up. South Asian cases had a higher relative survival than non-South Asians throughout the follow-up period. The 10-year relative survival rates were 72.6% (95% confidence interval: 69.0, 75.9%) and 65.2% (64.5, 65.8%) for South Asians and non-South Asians, respectively. The excess mortality rates experienced by South Asians were 82% (72, 94%) of those experienced by non-South Asians (P=0.004). The magnitude of this effect was slightly reduced with adjustment for differences in age at diagnosis, but was strengthened with further adjustment for differences in stage at presentation and socioeconomic deprivation (excess mortality rates in South Asians relative to non-South Asians=72% (63, 82%), P&<0.001). These findings indicate that the higher survival from breast cancer in the first 10 years after diagnosis among South Asian was not due to differences in age at diagnosis, socioeconomic deprivation or disease stage at presentation.

Diet and breast cancer: evidence that extremes in diet are associated with poor survival

PURPOSE

Diet has been postulated to influence breast cancer prognosis; however, existing evidence is weak and inconsistent. Previous studies have sought evidence of a linear relationship between diet and breast cancer outcomes. Because of a U-shaped association of body mass index (BMI) with survival in breast cancer, we hypothesized that a nonlinear association also existed for dietary variables.

PATIENTS AND METHODS

Four hundred seventy-seven women with surgically resected T1 to T3, N0/1, M0 breast cancer completed the Block Food Frequency Questionnaire 9.3 +/- 4.6 weeks (mean +/- standard deviation) after diagnosis, reporting intake over the preceding 12 months. Data on tumor-related factors, treatment, and outcomes were obtained prospectively from medical records. A series of Cox models was performed, modeling the association of dietary factors with breast cancer survival linearly and quadratically, adjusting for total energy intake, tumor- and treatment-related variables, and BMI.

RESULTS

Significant nonlinear survival associations were found for protein, oleic acid, cholesterol, polyunsaturated-saturated fat ratio, and for percentage of calories from fat and percentage of calories from carbohydrates in multivariate models. The shape of the survival associations varied across nutrients. Hazard ratios for highest risk quintiles ranged from 2.1 to 6.5. For total fat, adjustment for BMI reduced the multivariate P value obtained from nonlinear Cox models from.05 to.10. No significant linear associations were identified.

CONCLUSION

The association of key dietary variables with breast cancer survival may be U-shaped rather than linear. Our data suggest that midrange intake of most major energy sources is associated with the most favorable outcomes, and extremes are associated with less favorable outcomes.

Diet and breast cancer

Obesity, overweight, and a sedentary lifestyle-all common conditions in breast cancer patients-are likely to be associated with poor survival and poor quality of life in women with breast cancer. Diet-related factors are thought to account for about 30% of cancers in developed countries. Most studies of diet and healthcare have focused on the role of single nutrients, foods, or food groups in disease prevention or promotion. Recent cancer guidelines on nutrition and physical activity emphasize diets that promote maintenance of a healthy body weight and a prudent dietary pattern that is low in red and processed meats and high in a variety of vegetables, fruits, and whole grains. Except for dietary fat, few nutritional factors in adult life have been associated with breast cancer. Extensive data from animal model research, international correlations linking fat intake and breast cancer rates, and case-control studies support the hypothesis that a high-fat diet is conducive to the development of breast cancer in postmenopausal women. Conflicting findings from cohort studies, however, have created uncertainty over the role of dietary fat in breast cancer growth and recurrence. Results from large-scale nutritional intervention trials are expected to resolve such issues. As new and improved data on dietary factors and patterns accumulate, dietary guidelines for cancer risk reduction will become more focused.

Diet and breast cancer: can dietary factors influence survival?

Breast cancer accounts for over one third of invasive cancers in women. Earlier detection and improved initial treatments have resulted in an increasing number of women who have completed standard treatments but who remain at risk for breast cancer recurrence or early death. Epidemiological studies have linked diet composition with prognosis, and many women attempt to modify their diets and improve nutritional status following diagnosis The hypothesis that dietary factors may reduce risk for secondary cancer events and increase survival in this population is currently under study in two large randomized clinical trials: the Women's Intervention Nutrition Study (WINS) and the Women's Healthy Eating and Living (WHEL) Study. The WHEL Study is testing the effect of a diet high in vegetables, fruit, and fiber, and low in fat, on disease-free survival in women with early stage breast cancer. Hypothesized mechanisms include effects of diet modification on gonadal hormones, retinoid-like activities of carotenoids, and other protective effects of biologically active dietary constituents.

Can lifestyle modification increase survival in women diagnosed with breast cancer?

Epidemiologic studies have linked diets high in vegetables and fruit with an increased likelihood of survival after the diagnosis of breast cancer, and clinical and epidemiologic studies have identified obesity as an important negative prognostic factor. Of the 26 studies published since 1990 that examined the relationship with obesity and survival, 17 reported a significant inverse relationship. Five of the eight cohort studies of breast cancer survivors that examined intakes of vegetables, fruit and related micronutrients published since 1985 reported a positive relationship between these factors and survival. The hypothesis that lifestyle factors such as diet and physical activity may improve the prognosis in women who have been diagnosed with breast cancer is currently under study. The Women's Healthy Eating and Living Study is a randomized controlled study that tests the effects of a diet high in vegetables, fruit and fiber and low in fat on disease-free survival after treatment for early stage breast cancer (n = 3109). In the Healthy Weight Management for Breast Cancer Survivors Study, a multifaceted approach to promoting weight loss and long-term weight maintenance is being tested in 85 women at risk for breast cancer recurrence. The intervention emphasizes increased physical activity, strategies to improve body image and self-acceptance, and cognitive-behavioral therapy to promote healthy eating attitudes and behaviors. The results of these studies will contribute to understanding the roles of diet and physical activity in the progression of breast cancer.

Nutrition and survival after the diagnosis of breast cancer: a review of the evidence

PURPOSE

To review and summarize evidence from clinical and epidemiologic studies that have examined the relationship between nutritional factors, survival, and recurrence after the diagnosis of breast cancer.

MATERIALS AND METHODS

Relevant clinical and epidemiologic studies were identified through a MEDLINE search. References of identified reports also were used to identify additional published articles for critical review.

RESULTS

Several nutritional factors modify the progression of disease and prognosis after the diagnosis of breast cancer. Overweight or obesity is associated with poorer prognosis in the majority of the studies that have examined this relationship. Treatment-related weight gain also may influence disease-free survival, reduce quality of life, and increase risk for comorbid conditions. Five of 12 studies that examined the relationship between dietary fat and survival found an inverse association, which was not evident on energy adjustment in most of these studies. The majority of the studies that examined intakes of vegetables or nutrients provided by vegetables and fruit found a direct [corrected] relationship with survival. Alcohol intake was not associated with survival in the majority of the studies that examined this relationship.

CONCLUSION

Much remains to be learned about the role of nutritional factors in survival after the diagnosis of breast cancer. Healthy weight control with an emphasis on exercise to preserve or increase lean muscle mass and a diet that includes nutrient-rich vegetables can be recommended. Diets that have adequate vegetables, fruit, whole grains, and low-fat dairy foods and that are low in saturated fat may help to lower overall disease risk in this population.

Biobehavioral outcomes following psychological interventions for cancer patients

Psychological interventions for adult cancer patients have primarily focused on reducing stress and enhancing quality of life. However, there has been expanded focus on biobehavioral outcomes--health behaviors, compliance, biologic responses, and disease outcomes--consistent with the Biobehavioral Model of cancer stress and disease course. The author reviewed this expanded focus in quasiexperimental and experimental studies of psychological interventions, provided methodologic detail, summarized findings, and highlighted novel contributions. A final section discussed methodologic issues, research directions, and challenges for the coming decade.

Biobehavioral outcomes following psychological interventions for cancer patients

Psychological interventions for adult cancer patients have primarily focused on reducing stress and enhancing quality of life. However, there has been expanded focus on biobehavioral outcomes--health behaviors, compliance, biologic responses, and disease outcomes--consistent with the Biobehavioral Model of cancer stress and disease course. The author reviewed this expanded focus in quasiexperimental and experimental studies of psychological interventions, provided methodologic detail, summarized findings, and highlighted novel contributions. A final section discussed methodologic issues, research directions, and challenges for the coming decade.

Weight loss in breast cancer patient management

PURPOSE

To systematically review and summarize evidence relevant to obesity and breast cancer clinical outcome, potential hormonal mediating mechanisms, and the current status of weight loss interventions for chronic disease management.

METHODS

A comprehensive, formal literature review was conducted to identify 5,687 citations with key information from 159 references summarized in text and tables. This process included a search for all breast cancer studies exploring associations among survival or recurrence and obesity at diagnosis or weight gain after diagnosis using prospective criteria.

RESULTS

On the basis of observational studies, women with breast cancer who are overweight or gain weight after diagnosis are found to be at greater risk for breast cancer recurrence and death compared with lighter women. Obesity is also associated with hormonal profiles likely to stimulate breast cancer growth. Recently, use of weight loss algorithms proven successful in other clinical settings that incorporate dietary therapy, physical activity, and ongoing behavior therapy have been endorsed by the National Institutes of Health and other health agencies.

CONCLUSION

Although definitive weight loss intervention trials in breast cancer patients remain to be conducted, the current evidence relating increased body weight to adverse breast cancer outcome and the documented favorable effects of weight loss on clinical outcome in other comorbid conditions support consideration of programs for weight loss in breast cancer patients. Recommendations for the clinical care of overweight or obese breast cancer patients are offered.

Self-reported dietary habits, overall dietary quality and symptomatology of breast cancer survivors: a cross-sectional examination

Little information is available about the relationship between quality of life of women who have survived breast cancer (specifically, symptoms including those of menopause and depression) and the quality of their diet. In this cross-sectional study, 117 women with known primary breast cancer completed a self-administered food frequency questionnaire (FFQ) reflecting usual diet during the past year, a Survey of Feelings and Attitudes using the Center for Epidemiologic Studies Depression scale (CES-D) and a survey that includes menopausal symptoms among others common to women with a history of breast cancer. When women's responses to the FFQ were scored using the Healthy Eating Index (HEI), most often diets were evaluated as those that 'need improvement' with a mean total HEI score of 67.2. With regard to the CES-D scores, study women averaged 9.5, with 19 women being classified as clinically depressed. HEI and CES-D scores were inversely related (p = -0.22, p = 0.02). A negative correlation was also observed between energy-adjusted calcium intakes and CES-D scores (p = -0.19, p = 0.04). Clinical depressed women had not only lower HEI scores and calcium intakes, but also lower grain and variety scores. Comparisons to national data for disease-free women and that available for those with breast cancer suggest that our study women consumed diets low in energy and dietary variety. Diet quality may be an important factor influencing the manifestation of depressive symptoms in breast cancer survivors or conversely, poorer diet quality may be an outcome of depression.

Fasting insulin and outcome in early-stage breast cancer: results of a prospective cohort study

PURPOSE

Insulin, a member of a family of growth factors that includes insulin-like growth factor (IGF)-I and IGF-II, exerts mitogenic effects on normal and malignant breast epithelial cells, acting via insulin and IGF-I receptors. Because of this and because of its recognized association with obesity, an adverse prognostic factor in breast cancer, we examined the prognostic associations of insulin in early-stage breast cancer.

PATIENTS AND METHODS

A cohort of 512 women without known diabetes, who had early-stage (T1 to T3, N0 to N1, and M0) breast cancer, was assembled and observed prospectively. Information on traditional prognostic factors and body size was collected, and fasting blood was obtained.

RESULTS

Fasting insulin was associated with distant recurrence and death; the hazard ratios and 95% confidence intervals (CI) for those in the highest (> 51.9 pmol/L) versus the lowest (< 27.0 pmol/L) insulin quartile were 2.0 (95% CI, 1.2 to 3.3) and 3.1 (95% CI, 1.7 to 5.7), respectively. There was some evidence to suggest that the association of insulin with breast cancer outcomes may be nonlinear. Insulin was correlated with body mass index (Spearman r = 0.59, P <.001), which, in turn, was associated with distant recurrence and death (P <.001). In multivariate analyses that included fasting insulin and available tumor- and treatment-related variables, adjusted hazard ratios for the upper versus lower insulin quartile were 2.1 (95% CI, 1.2 to 3.6) and 3.3 (95% CI, 1.5 to 7.0) for distant recurrence and death, respectively.

CONCLUSION

Fasting insulin level is associated with outcome in women with early breast cancer. High levels of fasting insulin identify women with poor outcomes in whom more effective treatment strategies should be explored.

Breast cancer incidence in ex-smokers in relation to body mass index, weight gain and blood lipid levels

According to several studies breast cancer is more common among former smokers. This study explores whether this association has any relationship with anthropometric measurements or blood lipid levels. The 2082 ex-smokers (mean age 49.9 years) in the Malmö Preventive Cohort were followed for an average of 13.3 years using official cancer registries. This yielded 93 incident breast cancer cases. Oestrogen receptor (ER) status was assessed by an immunological method. Incidence of breast cancer covaried with height, body mass index, weight gain and cholesterol levels. None of these associations reached statistical significance. Incidence of breast cancer increased over quartiles of serum triglycerides, Ptrend: 0.02, relative risk (RR) for triglycerides as a continuous variable: 1.46 (1.21-1.77). Nineteen tumours were ER negative; this subgroup was similarly related to high triglycerides, 1.76 (1.40-2.21). All results were similar when BMI and cholesterol levels were entered into the model. It is concluded that breast cancer incidence covaries with triglyceride levels in ex-smokers.

Change in women's diet and body mass following intensive intervention for early-stage breast cancer

OBJECTIVE

To determine the effectiveness of an intensive dietary intervention on diet and body mass in women with breast cancer.

DESIGN

Randomized clinical trial.

SUBJECTS

172 women aged 20 to 65 years with stage I or II breast cancer.

INTERVENTION

A 15-session, mainly group-based and dietitian-led nutrition education program (NEP) was compared to a mindfulness-based stress reduction clinic program (SRC); or usual supportive care (UC).

MAIN OUTCOME MEASURES

Dietary fat, complex carbohydrates, fiber, and body mass were measured.

STATISTICAL ANALYSIS

In addition to descriptive statistics, analysis of variance was conducted to test for differences according to intervention group.

RESULTS

Of the 157 women with complete dietary data at baseline, 149 had complete data immediately postintervention (at 4 months) and 146 had complete data at 1 year. Women randomized to NEP (n = 50) experienced a large reduction in fat consumption (5.8% of energy as fat) at 4 months and much of this reduction was preserved at 1 year (4.1% of energy) (both P < .0002) vs no change in either SRC (n = 51) or UC (n = 56). A 1.3-kg reduction in body mass was evident at 4 months in the NEP group (P = .003) vs no change in the SRC and UC groups. Women who had higher-than-average expectations of a beneficial effect of the intervention experienced larger changes.

APPLICATIONS

Dietitians' use of group nutrition interventions appear to be warranted. Increasing their effectiveness and maintaining high levels of adherence may require additional support, including the involvement of significant others, periodic individual meetings, or group booster sessions.

The impact of marital status on cancer survival

Marital differentials in survival from 12 common types of cancer are assessed by estimating a mixed additive multiplicative hazard regression model on the basis of individual register and census data for the whole Norwegian population. These data cover the period 1960-91 and include more than 100,000 cancer deaths. The data and method make it possible to take into account the marital mortality differentialsin the absence of cancer. The excess all-cause mortality among cancer patients compared with similar persons without a cancer diagnosis is, on the whole, more than 15% higher for never-married men, never-married women and divorced men, than for the married of the same sex. Other previously married have an excess mortality elevated by about 7%. This protective effect of marriage is not due to stage, which is controlled for. The possible importance of treatment and host factors is discussed.

Inflammatory breast cancer survival: the role of obesity and menopausal status at diagnosis

No previous studies have evaluated the effect of body size and menopausal status at diagnosis on survival from inflammatory breast cancer (IBC). We evaluated whether obesity and menopausal status had an impact on IBC survival in a cohort of 177 female IBC patients seen from 1974 to 1993 at The University of Texas MD Anderson Cancer Center. Survival time was defined as time from diagnosis until death or censorship at last date of contact. We categorized women by body size by using the National Institutes of Health/National Heart, Lung, and Blood Institute's definitions of obesity as body mass index ((BMI) = weight in kg/(height in m)2) > or = 30, overweight as 25 < or = BMI < 30kg/m2, and normal/lean as BMI < 25 kg/m2. Cox proportional hazards analysis, adjusting for axillary lymph node involvement and chemotherapy protocol, revealed a modifying effect of menopausal status at diagnosis on the association between obesity and IBC survival (P = 0.02). Relative to postmenopausal women, premenopausal women had significantly worse survival (hazard ratio (HR) = 1.51, 95% confidence interval (CI) = 1.03-2.22). After stratifying by menopausal status, premenopausal obese women had non-significantly better survival than their leaner premenopausal counterparts (HR = 0.63, 95% CI = 0.34-1.15) while postmenopausal obese women had significantly worse survival than their leaner counterparts (HR = 1.86, 95% CI = 1.02-3.40). These findings suggest that factors associated with larger body size at diagnosis may contribute to shorter IBC survival among postmenopausal women but not premenopausal women, who were found to have poorer survival regardless of body size.

Android obesity at diagnosis and breast carcinoma survival: Evaluation of the effects of anthropometric variables at diagnosis, including body composition and body fat distribution and weight gain during life span,and survival from breast carcinoma

BACKGROUND

Although a large body of research exists concerning pathologic prognostic indicators of the rate of incidence and survival from breast carcinoma, to the authors' knowledge very few studies have examined the effects of anthropometric variables such as height, obesity, weight gain in adulthood, timing of weight gain, and body composition to survival, although these variables are related to the incidence rate.

METHODS

The survival status of 166 patients diagnosed with primary breast carcinoma and followed for at least 10 years was obtained from the Cancer Center's registry, and significant anthropometric and other known prognostic indicators regarding survival after diagnosis were determined by Cox proportional hazards analysis.

RESULTS

Eighty-three of 166 breast carcinoma patients (50%) with up to 10 years of follow-up died of disease. Android body fat distribution, as indicated by a higher suprailiac:thigh ratio, was a statistically significant (P < 0.0001) prognostic indicator for survival after controlling for stage of disease, with a hazards ratio of 2.6 (95% confidence interval [95% CI], 1.63-4.17). Adult weight gain, as indicated specifically by weight at age 30 years, was a statistically significant (P < 0.05) prognostic indicator for survival with a hazards ratio of 1.15 (95% CI, 1.0-1.28). In addition, the authors observed the Quatelet Index, a negatively significant (P < 0.01) prognostic indicator for survival with a hazards ratio of 0.92 (95% CI, 0.87-0.98). Other markers of general obesity such as weight at diagnosis, percent body fat, and body surface area were not significant markers influencing survival. Similarly, height; triceps, biceps; subscapular, suprailiac, abdominal, and thigh skinfolds; waist and hip circumferences; family history; and reproductive and hormonal variables at the time of diagnosis showed no apparent significant relation to survival.

CONCLUSIONS

The results of the current study provide some evidence that android body fat distribution at diagnosis and increased weight at age 30 years increases a woman's risk of dying of breast carcinoma.

Intra-urban differences in breast cancer mortality: a study from the city of Malmö in Sweden

STUDY OBJECTIVE

To assess whether in an urban population stage at breast cancer diagnosis is related to area of living and to what extent intra-urban differences in breast cancer mortality are related to incidence respectively stage at diagnosis.

DESIGN

National registries were used to identify cases. Mortality in 17 residential areas was studied in relation to incidence and stage distribution using linear regression analysis. Areas with high and low breast cancer mortality, incidence and proportion of stage II+ tumours at diagnosis were also compared in terms of their sociodemographic profile.

SETTING

City of Malmö in southern Sweden.

PATIENTS

The 1675 incident breast cancer cases and 448 deaths that occurred in women above 45 years of age in Malmö 1986-96.

MAIN RESULTS

Average annual age standardised breast cancer mortality ranged between residential areas, from 35/10(5) to 107/10(5), p = 0.04. Mortality of breast cancer was not correlated to incidence, r = 0.22, p = 0.39. The ratio of stage II+/0-I cancer incidence varied between areas from 0.45 to 1.99 and was significantly correlated to breast cancer mortality, r = 0.53, p = 0.03. Areas with high proportion of stage II+ cancers and high mortality/incidence ratio were characterised by a high proportion of residentials receiving income support, being foreigners and current smokers.

CONCLUSIONS

Within this urban population there were marked differences in breast cancer mortality between residential areas. Stage at diagnosis, but not incidence, contributed to the pattern of mortality. Areas with high proportion of stage II+ tumours differed unfavourably in several sociodemographic aspects from the city average.

Organochlorine exposure and breast cancer survival

Recent research suggests that exposure to organochlorines, such as dieldrin that possess estrogenic properties, may increase the risk of breast cancer by promoting growth of malignant cells. Whether this potential also affects malignant cells not eradicated by treatment, and thereby survival, is unknown. To evaluate this blood samples from female participants in the Copenhagen City Heart Study, Denmark, were analyzed for organochlorines. A total of 195 breast cancer cases, who each provided two blood samples that were taken in 1976-78 and 1981-83, respectively, were included in the survival analysis. Dieldrin had a significant adverse effect on overall survival and breast cancer specific survival (RR, 2.78, 95% CI, 1. 38-5.59, P trend < 0.01; RR, 2.61, 95% CI, 0.97-7.01, P trend < 0. 01). This association was strengthened when exposure was assessed as the average serum concentration of the two measurements. These findings suggest that past exposure to estrogenic organochlorines such as dieldrin may not only affect the risk of developing breast cancer but also the survival.

Factors associated with weight gain in women after diagnosis of breast cancer. Women's Healthy Eating and Living Study Group

OBJECTIVE

To identify the factors associated with weight gain after diagnosis of breast cancer in a heterogeneous population of women.

DESIGN

Descriptive cross-sectional study.

SUBJECTS

1,116 patients who had been diagnosed with stage I, stage II, or stage IIIA primary, operable breast cancer within the previous 4 years. Patients were recruited during enrollment into a diet intervention trial to reduce risk for breast cancer recurrence. Analysis Demographic data, weight history, and physical activity information obtained by questionnaire and medical information obtained by chart review; dietary assessment based on four 24-hour dietary recalls collected by telephone. Associations between weight change after the diagnosis of breast cancer and prediction variables were examined using univariate and multiple linear regression analyses.

RESULTS

Overall, 60% of the subjects reported weight gain, 26% reported weight loss, and 14% reported no change in weight after the diagnosis of breast cancer. The overall mean weight change was a gain of 2.7 kg (6 lb). Factors positively and independently associated with weight gain were time since diagnosis of breast cancer, adjuvant chemotherapy, African-American ethnicity, current energy intake, and postmenopausal status at time of study entry. Factors inversely and independently associated with weight gain were prediagnosis body mass index, age at diagnosis, education level, and exercise index score.

APPLICATIONS

Higher energy intake and lower level of physical activity are independently associated with increased risk for weight gain after the diagnosis of breast cancer. Strategies to modify these behaviors are likely to influence the long-term pattern of weight change.

Nutritional determinants of survival among patients with breast cancer

Recent data leave little doubt that nutritional factors modulate the growth of breast cancer cells. Nonetheless, the question of what type of diet is best for patients with a history of early-stage breast cancer or for patients with metastatic breast cancer continues to loom despite a growing number of studies on nutrition and cancer. Recommendations for the general population from the American Cancer Society and the Dietary Guidelines for Americans outline 25% of calories from fat, multiple servings of fruits and vegetables, and an emphasis on eating a variety of different foods. Although these recommendations likely constitute prudent advice for patients with breast cancer who have completed treatment for early-stage disease, they remain unproved. Specific, beneficial recommendations for patients currently receiving adjuvant chemotherapy or for patients with metastatic disease may well differ from those for the general population. Future clinical trials will play an important role in clarifying such issues.

Dietary factors and the survival of women with breast carcinoma

BACKGROUND

Little is known regarding how specific dietary factors affect the survival of women with breast carcinoma.

METHODS

Female registered nurses were followed with biennial questionnaires in a prospective cohort with 18 years of follow-up. Participants were women with breast carcinoma (n = 1982) diagnosed between 1976-1990 who completed a food frequency questionnaire after diagnosis. The main outcome measure was time to death from any cause. Analysis was made by multivariate Cox proportional hazards models.

RESULTS

In multivariate analyses of diet after diagnosis, no apparent association was found between fat intake and mortality. The relative risk (and 95% confidence interval) of mortality comparing the highest with the lowest quintile of protein intake was 0.65 (0.47-0.88). There was no association between red meat and mortality. These associations were similar in analyses with breast carcinoma death as the outcome.

CONCLUSIONS

No survival advantage was found for a low fat diet after a diagnosis of breast carcinoma. However, increased survival was observed among women eating more protein, but not red meat. The findings suggest that differences in diet may affect survival after a diagnosis of breast carcinoma and should be examined in greater detail.

The influence of maternal diet on breast cancer risk among female offspring

The induction of breast cancer is a long process, containing a series of biological events that drive a normal mammary cell towards malignant growth. However, it is not known when the initiation of breast cancer occurs. One hypothesis is that a high estrogenic environment during the perinatal period increases subsequent breast cancer risk. There are many sources of extragonadal estrogens, particularly in the diet. The purpose of this paper is to review the evidence that a high maternal intake of dietary fats increases serum estrogens during pregnancy and increases breast cancer risk in daughters. Our animal studies show that a high maternal consumption of corn oil consisting mainly of linoleic acid (omega-6 polyunsaturated fatty acid, PUFA), increases both circulating estradiol (E2) levels during pregnancy and the risk of developing carcinogen-induced mammary tumors among the female rat offspring. A similar increase in breast cancer risk occurs in female offspring exposed to injections of E2 through their pregnant mother. Our data suggest that the mechanisms by which an early exposure to dietary fat and/or estrogens increases breast cancer risk is related to reduced differentiation of the mammary epithelial tree and increased number of mammary epithelial cell structures that are known to the sites of neoplastic transformation. These findings may reflect our data of the reduced estrogen receptor protein levels and protein kinase C activity in the developing mammary glands of female rats exposed to a high-fat diet in utero. In summary, a high dietary linoleic acid intake can elevate pregnancy estrogen levels and this, possibly by altering mammary gland morphology and expression of fat- and/or estrogen-regulated genes, can increase breast cancer risk in the offspring. If true for women, breast cancer prevention in daughters may include modulating the mother's pregnancy intake of some dietary fats.

Hormones and breast cancer: evidence and implications for consideration of risks and benefits of hormone replacement therapy

The role of estrogen replacement therapy (ERT) in the etiology of breast cancer continues to be debated. The implications for counseling women about a causal relation between hormones and breast cancer with regard to long-term use of postmenopausal hormones remain controversial. The literature on hormones and breast cancer, including articles on cell proliferation, endogenous hormone levels, epidemiologic studies, and the risk of breast cancer, is reviewed. A cause of cancer is defined as a factor that increases the probability that cancer will develop in an individual. A causal relation between female hormones and breast cancer is based on duration of use, dose-response, biologic plausibility, temporality, strength of association, and coherence. The magnitude of the increase in risk of breast cancer caused by using hormone replacement therapy (HRT) is comparable to that seen in delayed menopause. The positive relation between endogenous hormone levels and risk of breast cancer supports a biologic mechanism for this relationship. The increase in risk of breast cancer with increasing duration of use, which does not vary substantially across studies, offers further evidence for a causal relation. The reduction in total mortality with short-term use of hormones, although strongest among women with risk factors for cardiovascular disease, adds complexity to the risk-benefit tradeoff associated with the use of hormones for longer durations. All evidence supports a causal relation between both endogenous estrogens and the use of postmenopausal estrogens and progestins and breast cancer incidence in postmenopausal women. Among postmenopausal women, prior use of oral contraceptives is not related to risk of breast cancer. Strategies for relief of menopausal symptoms and long-term prevention of osteoporosis and heart disease that do not cause breast cancer are urgently needed.

Adjuvant treatment and onset of menopause predict weight gain after breast cancer diagnosis

PURPOSE

Weight gain is common during the first year after breast cancer diagnosis. In this study, we examined clinical factors associated with body size at diagnosis and weight gain during the subsequent year.

PATIENTS AND METHODS

An inception cohort of 535 women with newly diagnosed locoregional breast cancer underwent anthropometric measurements at baseline and 1 year. Information was collected on tumor- and treatment-related variables, as well as diet and physical activity.

RESULTS

Mean age was 50.3 years; 57% of women were premenopausal. Mean baseline body mass index (weight [kg] divided by height [m] squared) was 25.5 kg/m2. Overall, 84.1% of the patients gained weight. Mean weight gain was 1.6 kg (95% confidence interval, 1.2 to 1.9 kg), 2.5 kg (95% confidence interval, 1.8 to 3.2 kg) in those receiving chemotherapy, 1.3 kg (95% confidence interval, 0.7 to 1.8 kg) in those receiving tamoxifen only, and 0.6 kg (95% confidence interval, 0.01 to 1.3 kg) in those receiving no adjuvant treatment. Menopausal status at diagnosis (P = .02), change in menopausal status over the subsequent year (P = .002), axillary nodal status (P = .009), and adjuvant treatment (P = .0002) predicted weight gain in univariate analysis. In multivariate analysis, onset of menopause and administration of chemotherapy were independent predictors of weight gain (all P < or = .05). Caloric intake decreased (P < .01) and physical activity increased (P < .05) during the year after diagnosis; these factors did not explain the observed weight gain.

CONCLUSION

Weight gain is common after breast cancer diagnosis; use of adjuvant chemotherapy and onset of menopause are the strongest clinical predictors of this weight gain.

The influence of sex hormones on obesity across the female life span

Women have a higher prevalence of obesity than men in most developed countries. Obesity affects many aspects of women's health by increasing risk for heart disease, diabetes, breast cancer, and infertility. One reason for the gender difference in obesity may be that fluctuations in reproductive hormone concentrations throughout women's lives uniquely predispose them to excess weight gain. Studies in experimental animals and women have shown that hormonal changes across the menstrual cycle affect calorie and macronutrient intake and alter 24-hour energy expenditure. Pregnancy is a significant factor in the development of obesity for many women. Various factors are associated with excess weight retention following pregnancy, including weight gain during pregnancy, ethnicity, dietary patterns, and interval between pregnancies. There is a need to tailor recommendations for energy intake during pregnancy to individual women, and recent evidence also suggests that the timing of weight gain during pregnancy is a critical factor. Menopause is also a high-risk time for weight gain in women. Although the average woman gains 2-5 pounds during menopausal transition, some women are at risk for greater weight gains. There is also a hormonally driven shift in body fat distribution from peripheral to abdominal at menopause, which may increase health risks in older women. Hormone therapies have varying impacts on body weight and fat distribution. In summary, hormonal fluctuations across the female life span may explain the increased risk for obesity in women. Awareness of these factors allows development of targets for prevention and early intervention.

Obesity as a risk factor for certain types of cancer

In conclusion, obesity has been associated with increased risk for a number of different types of cancer. The evidence has been most consistent for endometrial cancer, breast cancer in postmenopausal women, and renal cell cancer. More variable results have been reported for colorectal, prostate and pancreatic cancer. Possible mechanisms by which obesity may influence cancer risk include alteration in hormonal patterns, including sex hormones and insulin, and factors such as the distribution of body fat and changes in adiposity at different ages. The increasing prevalence of obesity in many parts of the world emphasizes the importance of learning more about the relationship between obesity and cancer and the mechanisms involved in their interaction.

The effect of dietary exposures on recurrence and mortality in early stage breast cancer

We studied the effect of diet and body weight on recurrence and death in 472 women diagnosed with early-stage breast cancer in 1982-1984. From Cox proportional hazards regression models we found that the strongest effects were observed in premenopausal women. For example, after accounting for disease stage and age, reported baseline consumption (times/day) of butter, margarine, and lard (risk ratio (RR)=1.67; 95% confidence interval (CI)=1.17-2.39) and beer (drinks/day) (RR=1.58; 95% CI=1.15-2.17) increased the risk of recurrence. There also appeared to be an increased risk associated with consumption of red meat, liver, and bacon, corresponding to about a doubling of risk for each time per day that foods in this category were consumed (RR=1.93; 95 % CI=0.89-4.15). Relative body weight increased risk at the rate of 9% (RR=1.09; 95% CI=1.02-1.17) for each kg/m2 (equivalent to about 5.8 pounds for a woman 5'4" tall). For death, the results were similar, but relative weight was more strongly associated, increasing risk by 12% per kg/m2 (RR=1.12; 95% CI=1.03-1.22).

Relationship between estrogen levels, use of hormone replacement therapy, and breast cancer

We sought to determine the strength of the evidence suggesting that estrogen and postmenopausal replacement hormones play a role in the development of breast cancer. We reviewed the existing English language literature in MEDLINE on hormones and breast cancer, including reports on cell proliferation and endogenous hormone levels, as well as epidemiologic studies of the relationship between the use of postmenopausal hormones and the risk of breast cancer in women. A factor that increases the probability that cancer will develop in an individual has been defined as a cancer cause. The Hill criteria for demonstrating a link between environmental factors and disease were used to review the evidence for a causal relationship between female hormones and breast cancer. We found evidence of a causal relationship between these hormones and breast cancer, based on the following criteria: consistency, dose-response pattern, biologic plausibility, temporality, strength of association, and coherence. The magnitude of the increase in breast cancer risk per year of hormone use is comparable to that associated with delaying menopause by a year. The positive relationship between endogenous hormone levels in postmenopausal women and risk of breast cancer supports a biologic mechanism for the relationship between use of hormones and increased risk of this disease. The finding that the increase in risk of breast cancer associated with increasing duration of hormone use does not vary substantially across studies offers further evidence for a causal relationship. We conclude that existing evidence supports a causal relationship between use of estrogens and progestins, levels of endogenous estrogens, and breast cancer incidence in postmenopausal women. Hormones may act to promote the late stages of carcinogenesis among postmenopausal women and to facilitate the proliferation of malignant cells. Strategies that do not cause breast cancer are urgently needed for the relief of menopausal symptoms and the long-term prevention of osteoporosis and heart disease.

Multidisciplinary weight management in locoregional breast cancer: results of a phase II study

Sixty-one women with newly diagnosed locoregional breast cancer (T1-3, N0-1, M0) having an initial Body Mass Index (BMI) between 20 and 35 kg/m2 who were receiving standard adjuvant treatment (chemotherapy, tamoxifen, and/or radiation) were asked to avoid weight gain (if initial BMI < or = 25 kg/m2) or to lose up to 10 kg (if initial BMI 25-35 kg/m2) over one year. Women participated in twenty group sessions (10 weekly, 10 monthly) which involved a psychological supportive-expressive group intervention supplemented by individual weight goals, and nutrition and exercise programs. Fifty-five non-censored women (5 developed recurrence, 1 died of a subarachnoid hemorrhage) lost a mean of 0.53 +/- 3.72 kg. Weight loss was greatest in initially overweight women (BMI > or = 25 kg/m2) who lost 1.63 +/- 4.11 kg (p = 0.01 compared to normal weight women) and in those not receiving chemotherapy who lost 2.15 +/- 2.83 kg (p = 0.0004 compared to those receiving chemotherapy). 70.9% met predefined criteria for success. Aerobic exercise increased significantly during the intervention (p = 0.00005) and was the strongest predictor of success (OR 1.73 for each additional 30 minutes of exercise weekly, p = 0.003). Changes in caloric intake were not significant, but fat intake decreased and carbohydrate and fibre intake increased significantly during the intervention. Eating behavior and psychological status improved significantly. Thus, this multidisciplinary weight management intervention successfully prevented weight gain in women with newly diagnosed locoregional breast cancer, and helped overweight women lose weight.

Chronic weight cycling increases oxidative DNA damage levels in mammary gland of female rats fed a high-fat diet

Oxidative DNA damage levels may be a marker of breast cancer risk that is modulated by diet. We examined the effects of a high-fat diet fed in varying feeding regimens on levels of 5-hydroxymethyl-2'-deoxyuridine (5-OHmU), an oxidized thymidine residue, in DNA from mammary gland of aging female rats. A total of 48 rats were randomly divided into four groups: ad libitum fed (AL), weight cycled above baseline (WC-G), weight cycled below baseline (WC-L), or energy restricted (ER) for 28 weeks. WC groups were fed repeated ad libitum/restricted amounts of the diet. At sacrifice, both WC groups had body weights similar to the ER group but higher levels of 5-OHmU (p < 0.01). 5-OHmU levels were higher in the WC groups than in the AL group, even though body weights of the WC groups were significantly lower (p < 0.001). These results indicate that a history of weight cycling, even when body weight is reduced, can have adverse effects on 5-OHmU levels in mammary gland DNA, a potential biomarker of cancer risk. Constant control of calories for the maintenance of body weight, therefore, may be more beneficial.

Mechanisms by which high maternal fat intake during pregnancy increases breast cancer risk in female rodent offspring

Emerging evidence indicates that a high in utero estrogenic environment increases breast cancer risk in women. We have proposed that a maternal intake of a high-fat diet is a source for high pregnancy estrogen levels and increases breast cancer risk among female offspring. In this review, the role of dietary fat in breast cancer, particularly during fetal life, is discussed. In addition, we provide possible mechanisms of action of the effects of a high-fat diet on the breast. These mechanisms include protein kinase C, estrogens and estrogen receptor, and alterations in mammary parenchymal structures.