The Role of Diet in Prognosis among Cancer Survivors: A Systematic Review and Meta-Analysis of Dietary Patterns and Diet Interventions

Cancer survival continues to improve in high-income countries, partly explained by advances in screening and treatment. Previous studies have mainly examined the relationship between individual dietary components and cancer prognosis in tumours with good therapeutic response (breast, colon and prostate cancers). The aim of this review is to assess qualitatively (and quantitatively where appropriate) the associations of dietary patterns and cancer prognosis from published prospective cohort studies, as well as the effect of diet interventions by means of randomised controlled trials (RCT). A systematic search was conducted in PubMed, and a total of 35 prospective cohort studies and 14 RCT published between 2011 and 2021 were selected. Better overall diet quality was associated with improved survival among breast and colorectal cancer survivors; adherence to the Mediterranean diet was associated to lower risk of mortality in colorectal and prostate cancer survivors. A meta-analysis using a random-effects model showed that higher versus lower diet quality was associated with a 23% reduction in overall mortality in breast cancer survivors. There was evidence that dietary interventions, generally combined with physical activity, improved overall quality of life, though most studies were in breast cancer survivors. Further cohort and intervention studies in other cancers are needed to make more specific recommendations.     

Is soy consumption good or bad for the breast?

Genistein in soy activates estrogen receptor (ER)-α and ERβ and acts as an estradiol in multiple target tissues. Because estrogens increase breast cancer risk and genistein promotes the growth of ER-positive human breast cancer cells, it has remained unclear whether this isoflavone or soy is safe. Results reviewed here suggest that women consuming moderate amounts of soy throughout their life have lower breast cancer risk than women who do not consume soy; however, this protective effect may originate from soy intake early in life. We also review the literature regarding potential risks genistein poses for breast cancer survivors. Findings obtained in 2 recent human studies show that a moderate consumption of diet containing this isoflavone does not increase the risk of breast cancer recurrence in Western women, and Asian breast cancer survivors exhibit better prognosis if they continue consuming a soy diet. The mechanisms explaining the breast cancer risk-reducing effect of early soy intake or the protective effect in Asian breast cancer survivors remain to be established. We propose that the reduction in risk involves epigenetic changes that result in alterations in the expression of genes that regulate mammary epithelial cell fate, i.e. cell proliferation and differentiation. Lifetime soy consumption at a moderate level may prevent breast cancer recurrence through mechanisms that change the biology of tumors; e.g. women who consumed soy during childhood develop breast cancers that express significantly reduced Human epidermal growth factor receptor 2 levels. More research is needed to understand why soy intake during early life may both reduce breast cancer risk and risk of recurrence.     

Feasibility of a randomized trial of a high‐vegetable diet to prevent breast cancer recurrence

Epidemiologic evidence supports the concept that diet influences risk for breast cancer and suggests that prognosis after the diagnosis of breast cancer may also be related to modifiable nutritional factors. The purpose of this study was to investigate the feasibility of a randomized trial of a high‐vegetable, reduced‐fat, and increased‐fiber diet intervention to reduce risk for recurrence among breast cancer survivors. This major change in dietary pattern was promoted through intensive telephone counseling. Participants were 93 women who had been diagnosed with breast cancer (stages I, II, and IIIA) within the previous four years and who had completed their initial treatment. We assessed adherence to the study diet using repeated 24‐hour dietary recalls at 6 and 12 months and measurement of circulating carotenoid concentrations. Six months after randomization, the intervention group had significantly increased their mean intake of vegetables (+4.6 servings/day), fruit (+0.7 servings/day), and fiber (+6.4 g/1,000 kcal) and significantly reduced their intake of dietary fat (‐9.9% of energy) compared with the control group. Circulating concentrations of carotenoids also increased in the intervention group. These changes persisted at the 12‐month visit. Results of this study demonstrate that telephone counseling can be a useful approach in diet intervention and that breast cancer survivors can adopt and maintain a high‐vegetable, reduced‐fat dietary pattern.     

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.     

Changes in Dietary Intake of Methionine,Folate/Folic Acid and Vitamin B12 and Survival in Postmenopausal Women with Breast Cancer: A Prospective Cohort Study

Background: Previous experimental studies showed that limiting methionine in the diet of animals or in cell culture media suppresses mammary cancer cell proliferation or metastasis. However, no previous study has investigated the associations of changes in methionine intake with survival among breast cancer survivors. We aimed to examine the association between changes in dietary intake of methionine, folate/folic acid, and vitamin B12 from before to after diagnosis of breast cancer, and mortality among breast cancer survivors. Methods: We included 1553 postmenopausal women from the Women’s Health Initiative who were diagnosed with invasive breast cancer and completed a food frequency questionnaire both before and after breast cancer diagnosis. Multivariable Cox proportional hazards regression models were used to estimate adjusted hazard ratios (HRs) and 95% confidence (CIs) of all-cause and breast cancer mortality associated with changes in methionine intake and changes in folate/folic acid and vitamin B12 intake. Results: Relative to pre-diagnosis, 28% of women decreased methionine intake by ≥20%, 30% of women increased methionine intake by ≥20%, and 42% of women had a relatively stable methionine intake (±19.9%) following breast cancer diagnosis. During a mean 16.1 years of follow up, there were 772 deaths in total, including 195 deaths from breast cancer. Compared to women with relatively stable methionine intake, women with decreased methionine intake had lower risks of all-cause (HR 0.78, 95% CI 0.62–0.97) and breast cancer mortality (HR 0.58, 95% CI 0.37–0.91) in fully adjusted models. In contrast, increased methionine intake or changes in folate/folic acid or vitamin B12 intake were not associated with all-cause or breast cancer mortality. Conclusions: Among breast cancer survivors, decreased methionine intake after breast cancer diagnosis was associated with lower risk of all-cause and breast cancer mortality.     

Adherence to the Mediterranean Diet and Mortality after Breast Cancer

Adherence to Mediterranean diet has been consistently associated with a reduced mortality in the general population, but evidence for women with breast cancer is scanty. Methods: A cohort of 1453 women with breast cancer diagnosed between 1991 and 1994 in northern Italy was followed-up for vital status for 15 years after diagnosis. The pre-diagnostic habitual diet was assessed through a structured questionnaire and adherence to the Mediterranean diet was evaluated through the Mediterranean Diet Score. Hazard ratios (HR) of death with confidence intervals (CI) were estimated using Cox model, adjusting for potential confounders. Results: Compared to women who scarcely adhere to the Mediterranean diet (n = 332, 22.8%), those highly adherent (n = 500, 34.4%) reported higher intakes of carbohydrates, mono-unsaturated and poly-unsaturated fatty acids, vitamins, folate, and carotenoids, and lower intakes of cholesterol and animal proteins. Adherence to the Mediterranean diet was associated with a better prognosis: 15-year overall survival of 63.1% for high and 53.6% for low adherence, respectively (p = 0.013). HR for all-cause mortality was 0.72 (95% CI: 0.57−0.92) and HR for breast cancer mortality was 0.65 (95% CI: 0.43−0.98) for women 55 years and older. No significant association emerged for breast cancer mortality in the total cohort. Conclusions: Although dietary habits may have changed after breast cancer diagnosis, these findings indicate that women who ate according to the Mediterranean dietary pattern prior to their diagnosis may have greater chance of a favorable prognosis after breast cancer diagnosis compared to those who did not.     

Plant-Based Dietary Patterns and Breast Cancer Recurrence and Survival in the Pathways Study

Plant-based diets are recommended for cancer survivors, but their relationship with breast cancer outcomes has not been examined. We evaluated whether long-term concordance with plant-based diets reduced the risk of recurrence and mortality among a prospective cohort of 3646 women diagnosed with breast cancer from 2005 to 2013. Participants completed food frequency questionnaires at diagnosis and 6-, 25-, and 72-month follow-up, from which we derived plant-based diet indices, including overall (PDI), healthful (hPDI), and unhealthful (uPDI). We observed 461 recurrences and 653 deaths over a median follow-up of 9.51 years. Using multivariable-adjusted Cox proportional hazards models, we estimated hazard ratios (HR) and 95% confidence intervals for breast cancer recurrence and all-cause, breast-cancer-specific, and non-breast-cancer mortality. Increased concordance with hPDI was associated with a reduced hazard of all-cause (HR 0.93, 95% CI: 0.83–1.05) and non-breast-cancer mortality (HR 0.83, 95% CI: 0.71–0.98), whereas increased concordance with uPDI was associated with increased hazards (HR 1.07, 95% CI: 0.96–1.2 and HR 1.20, 95% CI: 1.02–1.41, respectively). No associations with recurrence or breast-cancer-specific mortality were observed. In conclusion, healthful vs. unhealthful plant-based dietary patterns had differing associations with mortality. To enhance overall survival, dietary recommendations for breast cancer patients should emphasize healthful plant foods.     

Dietary Intake,Supplement Use,and Survival Among Women Diagnosed With Early-Stage Breast Cancer

Previous studies examining the relationship between micronutrient intakes and survival following diagnosis of breast cancer have reported mixed results. This may be partly due to considerable variance in amounts of micronutrients consumed from diet and supplements across studies. Early-stage breast cancer survivors (N = 3081) completed four 24-h dietary and supplement recalls at the baseline assessment (1995 to 2000) and were followed for a median of 9.0 yr. Mean micronutrient intakes were compared to dietary reference intakes (DRI) to assess micronutrient adequacy for both users and nonusers of supplements. Cox regressions were performed to assess whether intakes of selected micronutrients were associated with all-cause mortality. Four hundred and twelve deaths occurred between baseline and August 2009. Among these women, more supplement users had adequate micronutrient intakes than nonusers for 15 out of 17 micronutrients. Less than 10% of supplement users (<2% of nonsupplement users) reported levels that exceeded the tolerable upper limit for each micronutrient except magnesium. After adjusting for age, tumor characteristics, and health status variables, micronutrient intakes were not significantly associated with all-cause mortality. Dietary supplements may improve overall micronutrient intakes of breast cancer survivors. However, vitamin and mineral intakes were not associated with all-cause mortality.     

The Role of Dietary Fat throughout the Prostate Cancer Trajectory

Prostate cancer is the second most common cancer diagnosed world-wide; however, patients demonstrate exceptionally high survival rates. Many lifestyle factors, including obesity and diet, are considered risk factors for advanced prostate cancer. Dietary fat is a fundamental contributor to obesity and may be specifically important for prostate cancer patients. Prostate cancer treatment can result in changes in body composition, affecting quality of life for survivors by increasing the risk of co-morbidities, like cardiovascular disease and diabetes. We aim to examine dietary fat throughout the prostate cancer treatment trajectory, including risk, cancer development and survivorship. Focusing on one specific nutrient throughout the prostate cancer trajectory provides a unique perspective of dietary fat in prostate cancer and the mechanisms that may exacerbate prostate cancer risk, progression and recurrence. Through this approach, we noted that high intake of dietary fat, especially, high intake of animal and saturated fats, may be associated with increased prostate cancer risk. In contrast, a low-fat diet, specifically low in saturated fat, may be beneficial for prostate cancer survivors by reducing tumor angiogenesis and cancer recurrence. The insulin-like growth factor (IGF)/Akt signaling pathway appears to be the key pathway moderating dietary fat intake and prostate cancer development and progression.     

The Role of Diet,Alcohol, BMI,and Physical Activity in Cancer Mortality: Summary Findings of the EPIC Study

Evidence on the impact of diet, alcohol, body-mass index (BMI), and physical activity on mortality due to cancer and other cancer-related outcomes is still scarce. Herein, we reviewed the contribution of the European Prospective Investigation into Cancer and Nutrition (EPIC) study to the current state of the art on the role of these factors in cancer mortality. We identified 45 studies using a rapid systematic review methodology. Dietary factors associated with reduced cancer mortality included raw vegetable intake; dietary fiber intake; the Mediterranean diet; other dietary scores; other diet patterns including low meat eaters, vegetarians/vegans, or fish eaters; dietary intake (or biomarkers) of some vitamins (e.g., vitamin D, vitamin K2, or Vitamin C); and intake of lignans. Physical activity and following healthy lifestyle recommendations also reduced cancer mortality risk. In contrast, dietary factors associated with higher cancer mortality risk included poor diet quality, consumption of alcohol and soft drinks including juice, and, to a lesser extent, intake of some fatty acids. Excess weight and obesity also increased the risk of cancer mortality. The EPIC study holds valuable information on diet and lifestyle factors and offers a unique opportunity to identify key diet-related factors for cancer mortality prevention.     

Usual Dietary Intake among Female Breast Cancer Survivors Is Not Significantly Different from Women with No Cancer History: Results of the National Health and Nutrition Examination Survey, 2003-2006

Dietary intake is a modifiable behavior that may reduce the risk of recurrence and death among breast cancer survivors. Cancer survivors are encouraged to consume a diet rich in fruit, vegetables, and whole grains and limit red meat, processed meat, and alcohol intake. Using data from the National Health and Nutrition Examination Survey (2003-2006), this study examined whether breast cancer survivors and women with no history of cancer differed in the distribution of usual intake of foods included in the dietary recommendations for preventing cancer and recurrences. Participants completed one or two 24-hour dietary recalls. The food groups included in this analysis were whole fruit; total vegetables; dark green and orange vegetables; whole grains; red meat; processed meat; alcohol; and calories from solid fat, alcohol, and added sugar. The National Cancer Institute Method was used to estimate the distribution of usual intake and to compare breast cancer survivors (n=102) to noncancer respondents (n=2,684). Using age and cancer survivor as covariates, subgroup estimates of usual intake were constructed. No significant group differences were found, except that survivors reported a greater intake of whole grains. More than 90% of both groups did not meet recommendations for fruits, vegetables, and whole grains; 75.4% and 70.2%, respectively, consumed less than the red meat recommendation; and <10% of either group met the recommendation for percent energy from solid fat, alcohol, and added sugar. The diet of breast cancer survivors was not significantly different from women with no history of cancer.     

Peer Reviewed: A Weight Loss Intervention for African American Breast Cancer Survivors, 2006

Introduction

Breast cancer survival rates are lower for African American women than for white women. Obesity, high-fat diets, and lack of regular physical activity increase risk for breast cancer recurrence, comorbid conditions, and premature death. Eighty-two percent of African American women are overweight or obese, partly because of unhealthy eating and exercise patterns. Although successful weight loss and lifestyle interventions for breast cancer survivors are documented, none has considered the needs of African American breast cancer survivors. This study assessed the feasibility and impact of Moving Forward, a culturally tailored weight loss program for African American breast cancer survivors.

Methods

The study used a pre-post design with a convenience sample of 23 African American breast cancer survivors. The 6-month intervention was theory-based and incorporated qualitative data from focus groups with the targeted community, urban African American breast cancer survivors. Data on weight, body mass index (BMI), diet, physical activity, social support, and quality of life were collected at baseline and at 6 months.

Results

After the intervention, we noted significant differences in weight, BMI, dietary fat intake, vegetable consumption, vigorous physical activity, and social support.

Conclusion

This is the first published report of Moving Forward, a weight loss intervention designed for African American breast cancer survivors. Although a randomized trial is needed to establish efficacy, the positive results of this intervention suggest that this weight loss intervention may be feasible for African American breast cancer survivors. Lifestyle interventions may reduce the disparities in breast cancer mortality rates.     

Dietary intake, supplement use, and survival among women diagnosed with early-stage breast cancer

Previous studies examining the relationship between micronutrient intakes and survival following diagnosis of breast cancer have reported mixed results. This may be partly due to considerable variance in amounts of micronutrients consumed from diet and supplements across studies. Early-stage breast cancer survivors (N = 3081) completed four 24-h dietary and supplement recalls at the baseline assessment (1995 to 2000) and were followed for a median of 9.0 yr. Mean micronutrient intakes were compared to dietary reference intakes (DRI) to assess micronutrient adequacy for both users and nonusers of supplements. Cox regressions were performed to assess whether intakes of selected micronutrients were associated with all-cause mortality. Four hundred and twelve deaths occurred between baseline and August 2009. Among these women, more supplement users had adequate micronutrient intakes than nonusers for 15 out of 17 micronutrients. Less than 10% of supplement users (<2% of nonsupplement users) reported levels that exceeded the tolerable upper limit for each micronutrient except magnesium. After adjusting for age, tumor characteristics, and health status variables, micronutrient intakes were not significantly associated with all-cause mortality. Dietary supplements may improve overall micronutrient intakes of breast cancer survivors. However, vitamin and mineral intakes were not associated with all-cause mortality.     

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.     

Dietary fat, fiber, vegetable, and micronutrients are associated with overall survival in postmenopausal women diagnosed with breast cancer

Relatively few studies have assessed the relationship between dietary intakes and survival after breast cancer diagnosis. We investigated the influence of diet, including dietary fat (percentage energy), fiber, vegetable, and fruit intakes, and micronutrients (folate, carotenoids, and vitamin C) on overall survival in women diagnosed with breast cancer. Subjects were postmenopausal women diagnosed with breast cancer (N = 516) between 1994 and 1995 with a mean survival time of 80 mo (SD: 18). Subjects completed a food frequency questionnaire for the year prior to diagnosis. Cox proportional hazards models were used to measure the relationship between dietary intakes and death due to any cause after breast cancer diagnosis. In the multivariate analysis, we found that the hazard ratio [HR and 95% confidence interval (CI)] of dying in the highest tertile compared to the lowest tertile of total fat, fiber, vegetable, and fruit was 3.12 (95% CI = 1.79-5.44), 0.48 (95% CI = 0.27-0.86), 0.57 (95% CI = 0.35-0.94), and 0.63 (95% CI = 0.38-1.05), respectively (P 相似文献   

Diet and prognosis of breast cancer.

The relationship between the occurrence of breast cancer and dietary intake, in particular a high-fat diet, has attracted much attention in recent years. In addition, the prognosis of breast cancer patients on the basis of dietary intake is also an interesting subject. The present study utilized breast cancer patients whose dietary intake was carefully assessed about one decade previously in a case-control study to determine whether dietary intake was indeed related to the patients' prognosis. The study included 212 patients who underwent a surgical operation between 1975 and 1978. They were followed-up until 1987, and a total of 47 breast cancer deaths were certified. The 5- and 10-year relative survival rates were 78.5% and 75.3%, respectively. The older patients tended to ingest smaller amounts of all nutrients, except animal fat from fish. Height was significantly correlated with total animal protein intake, whereas there was no significant correlation between body mass index and intake of any nutrient. Although the age-adjusted mean values of the nutrient intakes, other than vegetable fat, decreased with advancing stage, the differences were statistically insignificant. The results of multivariate analyses, in which some confounding factors (e.g., clinical stage) were adjusted using a proportional hazards model, showed that all hazards ratios in each nutrient were close to unity, and no dose-response relationship was seen. The present investigation did not provide any support for the hypothesis that a high-fat diet is a survival determinant for breast cancer patients.(ABSTRACT TRUNCATED AT 250 WORDS)     

Dietary Patterns in Puerto Rican and Mexican-American Breast Cancer Survivors: A Pilot Study

Breast cancer is the leading cause of cancer death among Hispanic women. Certain dietary factors have been associated with the risk of breast cancer recurrence, but data in Hispanic survivors is scarce. Objective: to examine dietary patterns and diet quality in two groups of Hispanic breast cancer survivors. Methods: 23 Mexican-American (MA) and 22 Puerto Rican (PR) female breast cancer survivors completed a culturally adapted validated food frequency questionnaire. Intake was standardized per 1000 kcal and compared to US Dietary Guidelines and the DASH-style diet adherence score was calculated. Results: Overweight/obese was 70 % in MA and 91 % in PR. PR consumed diets rich in fruit/100 % fruit juices and beans, while MA diets were high in vegetables, beans, and total grains. Both groups consumed high amounts of starchy vegetables, refined grains, animal protein and calories from solid fats and added sugars but low intakes of whole grains, dairy products and nuts and seeds. DASH scores were relatively low. Conclusion: MA and PR female breast cancer survivors have different dietary patterns but both groups had relatively low diet quality. These groups could benefit from culturally tailored interventions to improve diet quality, which could potentially reduce cancer recurrence. ClinicalTrials.gov Identifier NCT01504789.     

Dietary patterns differ between urban and rural older, long-term survivors of breast, prostate, and colorectal cancer and are associated with body mass index

BackgroundOlder adult cancer survivors are at greater risk of cancer recurrence and other comorbidities that can be prevented through improved diet and weight management. The tertiary prevention needs of rural-dwelling survivors can be even greater, yet little is known about rural and urban differences in lifestyle factors among this high-risk population.ObjectivesTo compare dietary patterns of urban and rural cancer survivors and to examine associations of dietary patterns with body mass index (BMI).DesignA secondary analysis was performed of baseline data from the Reach Out to Enhance Wellness (RENEW) trial, a diet and exercise intervention among overweight, long-term (≥5 years), older survivors of colorectal, breast, and prostate cancer. Survivors in the present analysis (n=729) underwent two 45- to 60-minute telephone surveys, which included two 24-hour dietary recalls. Principal components analysis and multivariable general linear models were used to derive dietary patterns and to evaluate associations between dietary patterns and BMI, respectively.ResultsPrincipal components analysis identified three primary dietary patterns among rural dwellers (high sweets and starches, high reduced-fat dairy, cereal, nuts, and fruits, and mixed) and three among urban dwellers (high fruits and vegetables, high meat and refined grains, and high sugar-sweetened beverages). Among rural survivors, greater adherence to the high reduced-fat dairy, cereal, nuts, and fruits pattern was positively associated with lower BMI (P trend <0.05), whereas higher scores on the mixed pattern was associated with greater BMI (P trend <0.05). Greater adherence to the high fruits and vegetables pattern among urban survivors was inversely associated with BMI (P trend <0.05).ConclusionsUrban and rural differences in dietary intake behavior should be considered in designing public health interventions among the increasing population of older cancer survivors. In addition, targeting overall dietary patterns might be one approach to help reduce the burden of obesity among this population.     

Marine fatty acid intake is associated with breast cancer prognosis

EPA and DHA, long-chain (n-3) PUFA largely obtained from fish, inhibit the proliferation of breast cancer cells in vitro and reduce the initiation and progression of breast tumors in laboratory animals. Our purpose in this analysis was to examine whether intake of these marine fatty acids (EPA and DHA) were associated with prognosis in a cohort of women who had been diagnosed and treated for early stage breast cancer (n = 3,081). Median follow-up was 7.3 y. Dietary intake was assessed using 24-h recalls (~4 recalls per dietary assessment obtained at 7 time points over 6 y). Survival models with time-dependent covariates were used to examine the association of repeated measures of dietary intake of EPA and DHA from food (i.e., marine sources) and supplements with disease-free survival and overall survival. Women with higher intakes of EPA and DHA from food had an approximate 25% reduced risk of additional breast cancer events [tertile 2: HR = 0.74 (95% CI = 0.58-0.94); tertile 3: HR = 0.72 (95% CI = 0.57-0.90)] compared with the lowest tertile of intake. Women with higher intakes of EPA and DHA from food had a dose-dependent reduced risk of all-cause mortality [tertile 2: HR = 0.75 (95% CI = 0.55-1.04); tertile 3: HR = 0.59 (95% CI = 0.43-0.82)]. EPA and DHA intake from fish oil supplements was not associated with breast cancer outcomes. The investigation indicates that marine fatty acids from food are associated with reduced risk of additional breast cancer events and all-cause mortality.     

Zinc and Breast Cancer Survival: A Prospective Cohort Study of Dietary Intake and Serum Levels

Zinc has been suggested to play a role in breast cancer progression; however, no previous study on zinc levels and the potential effect on breast cancer survival has been conducted. This study investigates recurrence-free survival (RFS), breast cancer-specific survival (BCSS) and overall survival (OS) in relation to zinc levels, in serum and diet, overall and stratified for phosphorus and selenium levels. The Malmö Diet and Cancer Study, a prospective population-based cohort in Sweden including 17,035 women, was used to identify breast cancer patients diagnosed in the period 1991–2013. Diet was assessed by a validated modified diet history method. A Cox regression analysis yielded hazard ratios (HRs) with 95% confidence intervals adjusted for potential confounders. Out of 1062 patients with invasive breast cancer, 268 recurrences, 205 breast cancer deaths and 228 deaths from other causes were recorded. No overall associations were seen between zinc and RFS, BCSS or OS. However, in women with a high phosphorus intake, a higher BCSS and OS were seen in zinc intake Q2 to Q4 versus Q1; the adjusted HR was 0.41 (0.23–0.73) and 0.64 (0.41–1.00), respectively. The results indicate that the combination of intermediate/high zinc intake and high phosphorus intake may lead to a better breast cancer survival.