High-folate diets and breast cancer survival in a prospective cohort study

Phytotherapy and Nutritional Supplements on Breast Cancer

Breast cancer is the most frequent type of nonskin malignancy among women worldwide. In general, conventional cancer treatment options (i.e., surgery, radiotherapy, chemotherapy, biological therapy, and hormone therapy) are not completely effective. Recurrence and other pathologic situations are still an issue in breast cancer patients due to side effects, toxicity of drugs in normal cells, and aggressive behaviour of the tumours. From this point of view, breast cancer therapy and adjuvant methods represent a promising and challenging field for researchers. In the last few years, the use of some types of complementary medicines by women with a history of breast cancer has significantly increased such as phytotherapeutic products and nutritional supplements. Despite this, the use of such approaches in oncologic processes may be problematic and patient's health risks can arise such as interference with the efficacy of standard cancer treatment. The present review gives an overview of the most usual phytotherapeutic products and nutritional supplements with application in breast cancer patients as adjuvant approach. Regardless of the contradictory results of scientific evidence, we demonstrated the need to perform additional investigation, mainly well-designed clinical trials in order to establish correlations and allow for further validated outcomes concerning the efficacy, safety, and clinical evidence-based recommendation of these products.

Association between the dietary inflammatory index and breast cancer in a large Italian case-control study

INTRODUCTION

The putative relationship between diet, including its inflammatory potential, and breast cancer has been studied extensively, but results remain inconsistent. Using data from a large Italian case-control study conducted between 1991 and 1994, we examined the association between the dietary inflammatory index (DII) and odds of breast cancer.

METHODS

DII scores were computed using a validated 78-item food frequency questionnaire. Subjects were 2569 women with incident, histologically confirmed breast cancer and 2588 controls admitted to hospital for acute, non-hormone-related diseases. Odds ratios (ORs) and 95% confidence intervals (CIs) based on continuous and quintiles of DII were estimated by multiple logistic regression adjusting for age, study center, education, BMI, parity, menopausal status, family history of hormone-related cancers, and total energy intake.

RESULTS

Women in quintiles 2, 3, 4 and 5 had ORs of breast cancer of 1.33 (95% CI: 1.11, 1.59), 1.37 (95% CI: 1.13, 1.66), 1.41 (95% CI: 1.15, 1.73), and 1.75 (95% CI: 1.39, 2.21), respectively, compared to women in quintile 1. One-unit increase in DII increased the odds of having breast cancer by 9% (95% CI: 1.05, 1.14).

CONCLUSIONS

A pro-inflammatory diet is associated to increased risk of breast cancer.

Haplotypes of the MTHFR gene are associated with an increased risk of breast cancer in a Han Chinese population in Gansu province

Elevated homocysteine levels are a risk factor for breast cancer, although the mechanism underlying this effect is unknown. Genome-wide association studies were used to systematically identify genetic variants which were significantly associated with the circulating homocysteine concentration. To examine the role of homocysteine-related variants in the occurrence of breast cancer, we investigated the association between these variants and breast cancer in a Han Chinese population. Five variants of genome-wide significant homocysteine-related genes were selected for the analysis in a case-control study, with a total of 487 patients with breast cancer and 605 controls. We found that none of the studied polymorphisms were related to the altered breast cancer risk. In the haplotypic analysis, the 5,10-methylenetetrahydrofolate reductase (MTHFR) haplotypes rs12085006A/rs1999594G/rs1801133C (OR = 3.44, 95% CI = 1.58-7.50, P = 0.0019) and rs12085006A/rs1999594G/rs1801133T (OR = 16.21, 95% CI = 2.19- 120.32, P = 0.0065) were significantly associated with an increased breast cancer risk when compared with the wild-type haplotype. Both of the risky MTHFR haplotypes were correlated with decreased MTHFR gene expression and elevated homocysteine concentrations, indicating a genetic component for hyperhomocysteinemia. The MTHFR haplotypes reconstructed with homocysteine-related variants were associated with the occurrence of breast cancer. This finding further emphasizes the importance of homocysteine metabolism genes in breast carcinogenesis and highlights the interplay of diet, genetics, and human cancers. © 2016 IUBMB Life, 68(7):526-534, 2016.

Breast cancer survival among young women: a review of the role of modifiable lifestyle factors

Almost 7 % of breast cancers are diagnosed among women age 40 years and younger in Western populations. Clinical outcomes among young women are worse. Early age-of-onset increases the risk of contralateral breast cancer, local and distant recurrence, and subsequent mortality. Breast cancers in young women (BCYW) are more likely to present with triple-negative (TNBC), TP53-positive, and HER-2 over-expressing tumors than among older women. However, despite these known differences in breast cancer outcomes and tumor subtypes, there is limited understanding of the basic biology, epidemiology, and optimal therapeutic strategies for BCYW. Several modifiable lifestyle factors associated with reduced risk of developing breast cancer have also been implicated in improved prognosis among breast cancer survivors of all ages. Given the treatment-related toxicities and the extended window for late effects, long-term lifestyle modifications potentially offer significant benefits to BCYW. In this review, we propose a model identifying three main areas of lifestyle factors (energy imbalance, inflammation, and dietary nutrient adequacy) that may influence survival in BCYW. In addition, we provide a summary of mechanisms of action and a synthesis of previous research on each of these topics.

Healthy Eating Index/Alternative Healthy Eating Index and Breast Cancer Mortality and Survival: A Systematic Review and Meta-analysis

OBJECTIVE

Breast cancer is the most common cancer in women worldwide. The effects of overall diet quality instead of single nutrients after breast cancer diagnosis on mortality have been a growing area of research interest. The aim of this systematic review was to investigate the relationship between the Healthy Eating Index (HEI)/the Alternative Healthy Eating Index (AHEI) and risk of breast cancer mortality or survival rates as a primary outcome, and some related inflammatory factors, as secondary outcomes among postdiagnosed women.

METHODS

This study methodology was performed based on the Preferred Reporting Item for Systematic Review and Meta-analysis statement recommendation and had been registered at PROSPERO (registration number: CRD42015015605). The systematic search was conducted in the electronic databases including PubMed, ISI, Scopus, Cochrane, and Google before July 2016. Researches that had not reported risk of breast cancer mortality or survival rates separately were excluded from the study. Similarly, this review excluded studies which only had examined the HEI or AHEI without reporting their association with the risk of mortality or survival rates.

RESULTS

After primary search, of 643 studies identified, 4 studies including eligible criteria were selected for the final assessment. All selected studies had been conducted in the USA and used self-report food-frequency questionnaire for diet quality assessment. In two studies HEI-2005, in one study AHEI, and in another study AHEI-2010 were applied. Meta-analysis result showed no significant association between these indexes and risk of breast cancer mortality/survival among women with this malignancy [relative risk: (RR) 1.04; 95% confidence interval (CI): 0.69-1.56; P = 0.87].

CONCLUSIONS

Regarding the adherence HEI/AHEI, we found no association between mentioned indexes and risk of mortality or survival from breast cancer in women with breast cancer. However, evidence in this field is limited and inconsistence and further studies are needed.

The association between circulating total folate and folate vitamers with overall survival after postmenopausal breast cancer diagnosis

We studied the relationship between plasma total folate and folate vitamer concentrations [5-methyltetrahydrofolic acid, pteroylglutamic acid (folic acid) and tetrahydrofolic acid] with overall survival after breast cancer diagnosis. A secondary aim was to assess the relationship between folic acid supplement use with circulating total folate and folate vitamer concentrations. Participants were postmenopausal women diagnosed with breast cancer (n = 498) with an average follow-up of 6.7 yr. Plasma total folate and folate vitamers were measured by isotope-dilution LC-MS/MS in samples collected at or postdiagnosis. Cox proportional multivariate hazards models (controlled for stage, age at diagnosis, body mass index, parity, hormone replacement therapy use, treatment, alcohol use, folic acid use, and energy intake), were used to assess overall survival after breast cancer diagnosis. We found that the relative risk of dying for women with plasma total folate concentrations in the highest quartile was 59% lower (hazard ratio: 0.41, 95% confidence interval: 0.19-0.90) compared with the lowest quartile. Data on supplement use showed that women taking folic acid supplements had significantly higher circulating total folate and folate vitamer concentrations (P < 0.0001), suggesting that increased folate consumption through diet and/or supplementation may improve prognosis after breast cancer diagnosis.

Are diet quality scores after breast cancer diagnosis associated with improved breast cancer survival?

Previous studies have found that diets rich in fruits and vegetables are associated with reduced breast cancer mortality. However, these eating patterns do not necessarily reflect overall diet quality. The association of breast cancer mortality with a priori defined dietary scores, which are based on recommended dietary guidelines and reflect diet quality, has not been evaluated. We hypothesized that diet quality indices based on recommended guidelines are associated with decreased risk of breast cancer and nonbreast cancer mortality in breast cancer survivors. We examined the association between the Dietary Approaches to Stop Hypertension (DASH) score, and the Alternative Healthy Eating Index (AHEI)-2010, and the risk of breast cancer mortality and total mortality among women from the Nurses' Health Study diagnosed with breast cancer. Adherence to DASH-style and AHEI-2010 diets were associated with reduced risk of nonbreast cancer mortality (comparing the fifth quintile with the first quintile, relative risk (RR) = 0.72, 95% confidence interval (CI): 0.53-0.99, P trend = 0.03 for DASH, and RR = 0.57, 95% CI: 0.42-0.77, P trend <0.0001 for AHEI-2010). Diet scores were not significantly associated with breast cancer mortality. Our findings suggest that adherence to a higher quality diet after breast cancer diagnosis does not considerably change the risk of breast cancer death and recurrence. However, healthy dietary choices after breast cancer were associated with reduced risk of nonbreast cancer mortality in women with breast cancer.

Postdiagnosis supplement use and breast cancer prognosis in the After Breast Cancer Pooling Project

Vitamin supplement use after breast cancer diagnosis is common, but little is known about long-term effects on recurrence and survival. We examined postdiagnosis supplement use and risk of death or recurrence in the After Breast Cancer Pooling Project, a consortium of four cohorts of 12,019 breast cancer survivors from the United States and China. Post-treatment supplement use (vitamins A, B, C, D, E, and multivitamins) was assessed 1-5 years postdiagnosis. Associations with risk of recurrence, breast cancer-specific mortality, or total mortality were analyzed in Cox proportional hazards models separately by cohort. Individual cohort results were combined using random effects meta-analysis. Interactions with smoking, treatment, and hormonal status were examined. In multivariate models, vitamin E was associated with a decreased risk of recurrence (RR: 0.88; 95 % CI 0.79-0.99), and vitamin C with decreased risk of death (RR: 0.81; 95 % CI 0.72-0.92). However, when supplements were mutually adjusted, all associations were attenuated. There were no statistically significant associations with breast cancer mortality. The use of antioxidant supplements (multivitamins, vitamin C, or E) was not associated with recurrence, but was associated with a 16 % decreased risk of death (95 % CI 0.72-0.99). In addition, vitamin D was associated with decreased risk of recurrence among ER positive, but not ER negative tumors (p-interaction = 0.01). In this large consortium of breast cancer survivors, post-treatment use of vitamin supplements was not associated with increased risk of recurrence or death. Post-treatment use of antioxidant supplements was associated with improved survival, but the associations with individual supplement were difficult to determine. Stratification by ER status and considering antioxidants as a group may be more clinically relevant when evaluating associations with cancer risk and mortality.

Prognosis of breast cancer is associated with one-carbon metabolism related nutrients among Korean women

Background

The 5-year survival rate for breast cancer among Korean women has increased steadily; however, breast cancer remains the leading cause of cancer mortality among women. One-carbon metabolism, which requires an adequate supply of methyl group donors and B vitamins, may affect the prognosis of breast cancer. This aim of this study was to investigate the associations of dietary intake of vitamin B₂, vitamin B₆ and folate before diagnosis on the prognosis of breast cancer.

Methods

We assessed the dietary intake using a food frequency questionnaire with 980 women who were newly diagnosed and histopathologically confirmed to have primary breast cancer from hospitals in Korea, and 141 disease progression events occurred. Cox’s proportional hazard regression models were used to estimate the hazard ratio (HR) and 95% confidence interval (95% CI) adjusting for age, education, recruitment sites, TNM stage, hormone status, nuclear grade and total calorie.

Results

There was no significant association between any one-carbon metabolism related nutrients (vitamin B₂, B₆ and folate) and the progression of breast cancer overall. However, one-carbon metabolism related nutrients were associated with disease progression in breast cancer patients stratified by subtypes. In ER + and/or PR + breast cancers, no association was observed; however, in ER–/PR– breast cancers, a high intake of vitamin B₂ and folate statistically elevated the HR of breast cancer progression (HR = 2.28; 95% CI, 1.20-4.35, HR = 1.84; 95% CI, 1.02-3.32, respectively) compared to a low intake. This positive association between the ER/PR status and progression of the disease was profound when the nutrient intakes were categorized in a combined score (P_interaction = 0.018). In ER–/PR– breast cancers, high combined scores were associated with a significantly poor DFS compared to those belonging to the low score group (HR = 3.84; 95% CI, 1.70-8.71).

Conclusions

In conclusion, our results suggest that one-carbon related nutrients have a role in the prognosis of breast cancer depending on the ER/PR status.

Folate intake and breast cancer mortality in a cohort of Swedish women

Folate may influence breast cancer development and progression through its role in one-carbon metabolism. However, epidemiologic data on the relation between folate and breast cancer survival are limited. We investigated whether dietary folate intake was associated with survival in 3,116 women diagnosed with breast cancer in the population-based Swedish Mammography Cohort. Participants completed a 67-item food frequency questionnaire in 1987. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (95% CIs) for death from breast cancer and death from any cause. During 25,716 person-years of follow-up from 1987 to 2008, there were 852 deaths with 381 breast cancer deaths. Dietary folate intake was inversely associated with breast cancer and overall mortality. Women in the highest quartile of folate intake had a multivariable HR (95% CI) of death from breast cancer of 0.78 (0.58-1.03) compared to those in the lowest quartile (P (trend) = 0.03). The corresponding HR (95% CI) for death from any cause was 0.79 (0.66-0.96; P (trend) = 0.004). The protective association between dietary folate intake and breast cancer death was strongest among those with ER-negative tumors (HR = 0.42; 95% = CI 0.22-0.79; P (trend) = 0.01) comparing the highest to lowest quartile. Our findings suggest that folate intake before breast cancer diagnosis may improve breast cancer and overall survival. While these findings need to be confirmed in future studies, they do offer assurance that dietary folate intake at the levels observed in our population does not unfavorably affect survival after breast cancer.

Diet quality indices and postmenopausal breast cancer survival

Research on diet in breast cancer survival has been focused on single nutrients or foods, particularly dietary fat, fruits, vegetables, fiber, and alcohol. We hypothesized that diet quality indices decrease the risk of total and non-breast-cancer-related deaths in women diagnosed with breast cancer. We evaluated 4 dietary quality scores: Alternate Healthy Eating Index (AHEI), Diet Quality Index-Revised (DQIR), Recommended Food Score (RFS), and the alternate Mediterranean Diet Score (aMED), among 2,729 women from the Nurses' Health Study with invasive Stage 1-3 breast cancer diagnosed between 1978 and 1998 with follow-up through 2004. In multivariate adjusted analyses, no association was found between diet quality indices and either total or non-breast-cancer-related deaths. However, a higher aMED score was associated with a lower risk of non-breast-cancer death in women with low physical activity; the RR comparing the highest to lowest tertile was 0.39 (95% CI, 0.20-0.75, P trend = 0.0004). Our results suggest that a higher-quality diet after breast cancer diagnosis does not considerably change the risk of death from breast cancer. However, healthy dietary choices may be important because women are at risk of death from non-breast-cancer-related causes affected by diet.

Alcohol and risk of breast cancer in Mexican women

BACKGROUND

Little is known about the relationship between alcohol intake and breast cancer risk among Mexican women. This association may be modified by folate and Vitamin B12.

METHODS

A population-based case-control study conducted in Mexico recruited 1,000 incident breast cancer cases aged 35-69 and 1,074 controls matched on age, region, and health care system. In-person interviews were conducted to assess breast cancer risk factors and recent diet using a food frequency questionnaire. Conditional logistic regression models estimated adjusted odds ratios and 95% confidence intervals.

RESULTS

Over one-half (57%) of cases and less than one-half of controls (45%) reported any lifetime alcohol consumption. Compared with never drinkers, women reporting ever drinking (Adjusted OR = 1.25, 95% CI = 0.99-1.58) had a greater odds of breast cancer. There was evidence for interaction in the association between ever consuming any alcohol and breast cancer by folate (p for interaction = 0.04) suggesting women with lower folate intake had a higher odds of breast cancer (Adjusted OR = 1.99, 95% CI = 1.26-3.16) compared to women with higher folate intake (OR = 1.12, 95% CI = 0.69-1.83).

CONCLUSIONS

Our findings support evidence that any alcohol intake increases risk of breast cancer. Insufficient intake of folate may further elevate risk for developing breast cancer among women who consume alcohol.

Dietary linoleic and oleic fatty acids in relation to severe depressed mood: 10 years follow-up of a national cohort

The influence of dietary fatty acids (FAs) other than omega-3 FAs on mood has been largely overlooked. The authors prospectively assessed the association between dietary linoleic and oleic FAs and the risk of severe depressed mood (SDM) among 4856 adults aged 25-74 years who were examined in 1971-1975 as a part of a national survey. Intakes of FAs were obtained at baseline from a 24-hour recall and categorized into thirds. SDM was defined as Center for Epidemiologic Studies Depression Scale scores at follow-up survey >or=22 or taking anti-depression medication. After an average of 10.6 years of follow-up, the proportion of individuals with SDM were 11.45 (SE=0.96) % and 17.45(1.05) % respectively among 1947 men and 2909 women. The odds ratios (ORs) were 1 (reference), 1.64(95% CI=1.06, 2.54) and 2.34 (1.41, 3.87) respectively for men with lowest, middle and highest third of linoleic FA intake (p for trend=0.001); the ORs were 1 (reference), 0.88 (0.56, 1.38) and 0.48 (0.25, 0.95) respectively for women with lowest, middle and highest third of oleic FA intake (p for trend=0.0347). No association was observed from saturated FA. These estimates were adjusted for fish consumption at baseline and major physical diseases at follow-up. The authors concluded that increased intake of oleic FA was associated with reduced risk among women while increased intake of linoleic FA was associated with increased risk of SDM among men.

Dietary folate and vitamin B12 intake before diagnosis decreases gastric cancer mortality risk among susceptible MTHFR 677TT carriers

OBJECTIVE

To assess gastric cancer survival in relation to dietary intake of methyl donors and the methylenetetrahydrofolate reductase 677C>T (MTHFR 677C>T) polymorphism.

METHODS

A prospective cohort of 257 incidental, histologically confirmed gastric cancer cases was assembled in January 2004 and followed until June 2006. Patients were recruited from the main oncology and/or gastroenterology units in Mexico City and were queried regarding their sociodemographic information, clinical history, and dietary habits 3 y before the onset of their symptoms. The intake of methyl donors was estimated with a food-frequency questionnaire and the MTHFR 677C>T polymorphisms were determined by polymerase chain reaction/restriction fragment length polymorphism analysis. Cox's multivariate regression models were used to estimate the mortality risk of gastric cancer.

RESULTS

MTHFR 677TT carriers with low folate and vitamin B12 intakes had the lowest survival rate in cases of gastric cancer. High intakes of folate and vitamin B12 before diagnosis was associated with decreased gastric cancer mortality risk in susceptible MTHFR 677TT carriers (mortality risk for folate 0.14, 95% confidence interval 0.04-0.46, P for trend=0.001; mortality risk for vitamin B12 0.23, 95% confidence interval 0.08-0.66, P for trend=0.008).

CONCLUSION

Folate and related B vitamins may be used as an intervention strategy to improve the survival outcome of gastric cancer.

One-carbon metabolism and breast cancer: an epidemiological perspective

One-carbon metabolism is a network of biological reactions that plays critical role in DNA methylation and DNA synthesis, and in turn, facilitates the cross-talk between genetic and epigenetic processes. Genetic polymorphisms and supplies of cofactors (e.g. folate, vitamins B) involved in this pathway have been shown to influence cancer risk and even survival. In this review, we summarized the epidemiological evidence for one-carbon metabolism, from both genetics and lifestyle aspects, in relation to breast cancer risk. We also discussed this pathway in relation to breast cancer survival and the modulation of one-carbon polymorphism in chemotherapy. Emerging evidence on modulation of DNA methylation by one-carbon metabolism suggests that disruption of epigenome might have been the underlying mechanism. More results are expected and will be translated to guidance to the general population for disease prevention as well as to clinicians for treatment and management of the disease.

Energy balance, physical activity, and cancer risk

This chapter posits that cancer is a complex and multifactorial process as demonstrated by the expression and production of key endocrine and steroid hormones that intermesh with lifestyle factors (physical activity, body size, and diet) in combination to heighten cancer risk. Excess weight has been associated with increased mortality from all cancers combined and for cancers of several specific sites. The prevalence of obesity has reached epidemic levels in many parts of the world; more than 1 billion adults are overweight with a body mass index (BMI) exceeding 25. Overweight and obesity are clinically defined indicators of a disease process characterized by the accumulation of body fat due to an excess of energy intake (nutritional intake) relative to energy expenditure (physical activity). When energy intake exceeds energy expenditure over a prolonged period of time, the result is a positive energy balance (PEB), which leads to the development of obesity. This physical state is ideal for intervention and can be modulated by changes in energy intake, expenditure, or both. Nutritional intake is a modifiable factor in the energy balance-cancer linkage primarily tested by caloric restriction studies in animals and the effect of energy availability. Restriction of calories by 10 to 40% has been shown to decrease cell proliferation, increasing apoptosis through anti-angiogenic processes. The potent anticancer effect of caloric restriction is clear, but caloric restriction alone is not generally considered to be a feasible strategy for cancer prevention in humans. Identification and development of preventive strategies that "mimic" the anticancer effects of low energy intake are desirable. The independent effect of energy intake on cancer risk has been difficult to estimate because body size and physical activity are strong determinants of total energy expenditure. The mechanisms that account for the inhibitory effects of physical activity on the carcinogenic process are reduction in fat stores, activity related changes in sex-hormone levels, altered immune function, effects in insulin and insulin-like growth factors, reduced free radical generation, and direct effect on the tumor. Epidemiologic evidence posits that the cascade of actions linking overweight and obesity to carcinogenesis are triggered by the endocrine and metabolic system. Perturbations to these systems result in the alterations in the levels of bioavailable growth factors, steroid hormones, and inflammatory markers. Elevated serum concentrations of insulin lead to a state of hyperinsulinemia. This physiological state causes a reduction in insulin-like growth factor-binding proteins and promotes the synthesis and biological activity of insulin-like growth factor (IGF)-I, which regulates cellular growth in response to available energy and nutrients from diet and body reserves. In vitro studies have clearly established that both insulin and IGF-I act as growth factors that promote cell proliferation and inhibit apoptosis. Insulin also affects on the synthesis and biological availability of the male and female sex steroids, including androgens, progesterone, and estrogens. Experimental and clinical evidence also indicates a central role of estrogens and progesterone in regulating cellular differentiation, proliferation, and apoptosis induction. Hyperinsulinemia is also associated with alterations in molecular systems such as endogenous hormones and adipokines that regulate inflammatory responses. Obesity-related dysregulation of adipokines has the ability to contribute to tumorigenesis and tumor invasion via metastatic potential. Given the substantial level of weight gain in industrialized countries in the last two decades, there is great interest in understanding all of the mechanisms by which obesity contributes to the carcinogenic process. Continued focus must be directed to understanding the various relationships between specific nutrients and dietary components and cancer cause and prevention. A reductionist approach is not sufficient for the basic biological mechanisms underlying the effect of diet and physical activity on cancer. The joint association between energy balance and cancer risk are hypothesized to share the same underlying mechanisms, the amplification of chemical mediators that modulate cancer risk depending on the responsiveness to those hormones to the target tissue of interest. Disentangling the connection between obesity, the insulin-IGF axis, endogenous hormones, inflammatory markers, and their molecular interaction is vital.

Modulation of response to cancer chemotherapeutic agents by diet constituents – Is the available evidence sufficiently robust for rational advice for patients?

BACKGROUND

Patients who are diagnosed with cancer want advice on how they may alter their diet or which diet supplements they should take to augment chemotherapy.

METHODS

We conducted a review of the literature mostly from the last 15 years on the interaction between dietary constituents and antineoplastic therapy in preclinical rodent models and in clinical trials.

RESULTS

Studies have explored the effect of predominantly antioxidant vitamins and folate on efficacy or toxicity mediated by cisplatin and anthracyclins. Cisplatin toxicity in rodents was ameliorated by vitamin E. The design of clinical studies of dietary agents in combination with cytotoxic agents has been very heterogeneous and results have been inconclusive.

CONCLUSIONS

Whilst preclinical experiments hint at a potential benefit of certain dietary agents, the evidence emanating from clinical studies does not allow firm conclusions to be made. Future studies should explore physiological doses of dietary agent and include pharmacokinetic and pharmacodynamic measurements.

Association of MTHFR gene polymorphisms with breast cancer survival

Background

Two functional single nucleotide polymorphisms (SNPs) in the 5,10-methylenetetrahydrofolate reductase (MTHFR) gene, C677T and A1298C, lead to decreased enzyme activity and affect chemosensitivity of tumor cells. We investigated whether these MTHFR SNPs were associated with breast cancer survival in African-American and Caucasian women.

Methods

African-American (n = 143) and Caucasian (n = 105) women, who had incident breast cancer with surgery, were recruited between 1993 and 2003 from the greater Baltimore area, Maryland, USA. Kaplan-Meier survival and multivariate Cox proportional hazards regression analyses were used to examine the relationship between MTHFR SNPs and disease-specific survival.

Results

We observed opposite effects of the MTHFR polymorphisms A1298C and C677T on breast cancer survival. Carriers of the variant allele at codon 1298 (A/C or C/C) had reduced survival when compared to homozygous carriers of the common A allele [Hazard ratio (HR) = 2.05; 95% confidence interval (CI), 1.05–4.00]. In contrast, breast cancer patients with the variant allele at codon 677 (C/T or T/T) had improved survival, albeit not statistically significant, when compared to individuals with the common C/C genotype (HR = 0.65; 95% CI, 0.31–1.35). The effects were stronger in patients with estrogen receptor-negative tumors (HR = 2.70; 95% CI, 1.17–6.23 for A/C or C/C versus A/A at codon 1298; HR = 0.36; 95% CI, 0.12–1.04 for C/T or T/T versus C/C at codon 677). Interactions between the two MTHFR genotypes and race/ethnicity on breast cancer survival were also observed (A1298C, p_interaction = 0.088; C677T, p_interaction = 0.026).

Conclusion

We found that the MTHFR SNPs, C677T and A1298C, were associated with breast cancer survival. The variant alleles had opposite effects on disease outcome in the study population. Race/ethnicity modified the association between the two SNPs and breast cancer survival.

Folate intake, alcohol use, and postmenopausal breast cancer risk in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial

BACKGROUND

Several epidemiologic studies suggest that higher folate intakes are associated with lower breast cancer risk, particularly in women with moderate alcohol consumption.

OBJECTIVE

We investigated the association between dietary folate, alcohol consumption, and postmenopausal breast cancer in women from the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial cohort.

DESIGN

Dietary data were collected at study enrollment between 1993 and 2001. Folate content was assigned on the basis of prefortification (ie, pre-1998) databases. Of the 25 400 women participants with a baseline age of 55-74 y and with complete dietary and multivitamin information, 691 developed breast cancer between September 1993 and May 2003. We used Cox proportional hazard models with age as the underlying time metric to generate hazard ratios (HRs) and 95% CIs.

RESULTS

The adjusted HRs were 1.19 (95% CI: 1.01, 1.41; P for trend = 0.04) for women reporting supplemental folic acid intake >/=400 mug/d compared with subjects reporting no supplemental intake. Comparison of the highest with the lowest quintile gave adjusted HRs of 1.04 (95% CI: 0.83, 1.31; P for trend = 0.56) and 1.32 (95% CI: 1.04, 1.68; P for trend = 0.03) for food and total folate intake, respectively. Alcohol consumption was positively associated with breast cancer risk (highest compared with lowest quintile: HR = 1.37; 95% CI: 1.08, 1.76; P for trend = 0.02); the risk was greatest in women with lower total folate intake.

CONCLUSIONS

Our results do not support the hypothesis that high folate intake reduces breast cancer risk; instead, they suggest that a high intake, generally attributable to supplemental folic acid, may increase the risk in postmenopausal women. However, our results confirm previous studies showing positive associations between moderate alcohol consumption and breast cancer.

Dietary Patterns and Survival After Breast Cancer Diagnosis

Purpose

There is little prior study of major dietary patterns and breast cancer survival.

Methods

Patients included 2,619 Nurses' Health Study participants who were diagnosed with invasive breast cancer between 1982 and 1998 and completed a dietary questionnaire more than 1 year after diagnosis. Participants were followed through 2002 (median = 9 years). During follow-up, 414 patients died of any cause, 242 patients died of breast cancer, and 172 patients died from causes other than breast cancer. Women with in situ or metastatic disease at diagnosis were excluded. We used Cox proportional hazards models to evaluate prospective associations of prudent and Western dietary patterns assessed both before and after diagnosis with time to event after diagnosis.

Results

In multivariate-adjusted analyses assessed after diagnosis, the Western and prudent dietary patterns were unrelated to all-cause or breast cancer mortality. However, compared with women with the lowest intake of the prudent dietary pattern, the relative risks (and 95% CIs) of death from causes other than breast cancer were 0.85 (95% CI, 0.53 to 1.35), 0.74 (95% CI, 0.45 to 1.21), 0.70 (95% CI, 0.42 to 1.17), and 0.54 (95% CI, 0.31 to 0.95; P = .03, from lowest to highest quintile of intake). In contrast, the Western dietary pattern was positively associated with this outcome (P = .04). Results for the assessment of dietary patterns before diagnosis were similar, except the prudent dietary pattern was unrelated to mortality.

Conclusion

A higher intake of the prudent pattern and a lower intake of the Western pattern may protect against mortality from causes unrelated to breast cancer.

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.