LIFESTYLE MANAGEMENT AND BREAST CANCER
In 2014, the American Institute for Cancer Research reported in their latest review of global research that diet, physical activity, and weight management play a major role in survival among patients with breast cancer.454 Research indicates that a lower BMI and eating a whole-food, plant-based diet (WFPBD), high in fiber and low in fats, improves survival in breast cancer. Maintaining health after a diagnosis of breast cancer requires a lifestyle transformation that helps fight cancer and prevents the development of other diseases that may lower survival. Thus, all patients should consider developing a lifestyle that includes a focus on the vital signs of health called the Wellness Index (WI).455 (The WI is shown in the Sidebar: The Breast Cancer Wellness Index.)
The goal of the WI is to determine the current state of health and then use the index to identify areas of opportunity to achieve total health during and after treatment. Achieving total health includes a focus on healthy eating, active living, and emotional resilience (HEALER). (See Sidebar: Healthy Eating, Active Living, and Emotional Resilience Goals.) Surviving breast cancer moves one into the HEALER zone, where patients maximize their abilities to prevent cancer recurrence while simultaneously optimizing their ability to treat and prevent chronic diseases such as obesity, DM, hypertension, hyperlipidemia, tobacco and/or alcohol abuse, and coronary artery disease. The WI appears in two parts. The first part is an objective measure of biometrics. This includes a report on BMI, blood pressure, blood glucose and hemoglobin A1c, and any current history of tobacco use or alcohol abuse. Biometrics is an objective measure of current health status. The second part, HEALER, subjectively assesses what lifestyle changes the patient is making to improve survival.
Surviving breast cancer involves a total-health care strategy. Women with breast cancer who are otherwise healthy have a better chance of survival than do unhealthy women. Biometrics and HEALER are considered total-health balance factors (Figure 2) because they describe the relationship of our current wellness state and our future lifestyle approaches. Healthy eating, active living, and BMI describe an energy balance that is the relationship between energy consumed (healthy eating), energy expended (physical activity), and energy stored (fat). BMI is defined as weight in kilograms divided by height in meters squared. In general, underweight is a BMI below 20 kg/m2, normal weight is a BMI of 21 to 25 kg/m2, overweight is a BMI of 25 to 29.9 kg/m2, and obesity refers to a BMI above 30 kg/m2.456
A positive energy balance results when energy intake exceeds energy expended (BMI increased); negative energy balance results when energy intake is less than energy expended (BMI decreased). Obesity, inactivity, and unhealthy eating are linked to decreased overall and cancer-specific survival in patients with breast cancer. Studies have demonstrated that interventions to maximize healthy eating and active living can improve quality of life and survival in patients with breast cancer.
Obesity is associated with an increased risk of postmenopausal breast cancer in population-based studies.457 Obesity at the time of diagnosis may limit the reduction in breast cancer mortality attainable through the detection and treatment of early-stage disease.458 In addition, obesity at diagnosis is associated with inferior outcomes in ER+ operable breast cancers.459 Obesity is a risk factor for breast cancer recurrence and mortality and an important outcome measure for overall health. Maintaining a healthy weight through programs such as HEALER is one of the most important interventions a patient with breast cancer can make to reduce the risk of breast cancer recurrence, mortality, and development of other chronic diseases.
A systematic literature review and meta-analysis of 82 follow-up studies on the relationship between BMI and breast cancer survival was reported in 2014.456 The report included 213,075 survivors of breast cancer and 41,477 deaths (23,182 deaths were attributed to breast cancer). For each 5 kg/m2 increment of BMI before breast cancer diagnosis, less than 12 months after diagnosis, and 12 or more months after diagnosis, increased risks were observed, respectively, of 17%, 11%, and 8% for overall mortality and 18%, 14%, and 29% for breast cancer-specific mortality. The authors concluded that obesity is associated with poorer OS and breast cancer survival regardless of when BMI is ascertained.456
Despite abundant data linking obesity to a poor prognosis in early-stage breast cancer, there have been relatively few studies evaluating the efficacy and potential benefits of weight loss interventions in survivors of breast cancer. In 2002, researchers performed a systematic review of 5687 literature citations to explore associations among survival and/or recurrence and obesity at diagnosis or weight gain after diagnosis of breast cancer. Results of this observational study showed that women with breast cancer who are overweight or gain weight after diagnosis are found to be at higher risk of breast cancer recurrence and death. The authors concluded that weight loss interventions should be considered in the total-health management of patients with breast cancer.460
Data from the Health, Eating, Activity, & Lifestyle Study suggest that increasing physical activity and decreasing body fat may be a reasonable intervention to decrease insulin and leptin levels, thereby potentially influencing breast cancer prognosis.461 Preventing weight gain by regular aerobic exercise in these women may be important in preventing recurrent disease.462 The strongest evidence that physical activity leading to weight loss and weight maintenance is associated with better outcomes of breast cancer comes from the Nurses’ Health Study.463 Weight management with diet and lifestyle changes should be an integral part of the follow-up of women with breast cancer.
Besides BMI, other biometrics are important for health. Women treated for cancer are also at risk of chronic diseases later in life. Controlling blood pressure, cholesterol, and fasting blood glucose/hemoglobin A1c and avoidance of tobacco and excessive alcohol consumption will help decrease the risk of death caused by chronic disease. For these reasons, women with a breast cancer diagnosis should also monitor and control the other biometrics listed to maintain good health. The HEALER interventions will help maintain a healthy BMI and reduce risks factors associated with the other chronic conditions mentioned.
Epidemiologic evidence shows that the risk of premature death due to coronary artery disease is increased in women who have uncontrolled hypertension, hyperlipidemia, and an elevated hemoglobin A1c level, and in those who smoke tobacco. The strong association observed between mortality and major cardiovascular risk factors makes the undertaking of multifactorial prevention strategies important. Lifestyle strongly influences the development of high blood pressure, high cholesterol, and DM in women. Therefore, women with uncontrolled risk factors for CVD should be seen by their primary care physician and treatment should be initiated to reduce the risk of CVD.464 Because some studies suggest that all types of alcohol may increase the risk of cancer, women with breast cancer should also limit alcohol intake.465
Women who smoke should stop. The relationship between breast cancer risk and active cigarette smoking remains controversial because of unresolved issues of confounding (alcohol intake) and dose response. To investigate these issues further, researchers analyzed data from 73,388 women in the American Cancer Society’s Cancer Prevention Study II Nutrition Cohort.466 Analyses were based on 3721 patients with invasive breast cancer identified during a median follow-up of 13.8 years. The results showed that breast cancer rates were higher in current and former smokers than in never smokers. In addition, the data showed that the risk of invasive breast cancer was highest in women who began smoking at an earlier age.466
Because a large portion of the life of a patient with breast cancer may be spent in survivorship, lifestyle interventions could have time to make a difference and should be included in the overall treatment plan of all patients who receive a breast cancer diagnosis. Assessing biometrics will help us understand opportunities for improvement that can be made as described in the next intervention, which includes healthy eating, active living, and developing emotional resilience as it relates to survivorship.
Healthy Eating, Active Living, and Emotional Resilience
Each year breast cancer is diagnosed in more than 240,000 women in the US. A high proportion of these patients are both obese and sedentary.467 Therefore, lifestyle interventions may be needed to improve health outcomes and prognosis. Recent studies demonstrate that weight loss interventions in breast cancer result in significant weight loss at 6, 12, and 18 months after diagnosis.468 A single-variable analysis in 2007 looked at the association between healthy eating, active living, and obesity with breast cancer survival in a prospective study that included 1490 women who underwent treatment of breast cancer.381 The results showed an association between reduced mortality and higher vegetable-fruit consumption, increased physical activity, and a BMI that was neither underweight nor obese.
An analysis of 85 studies that included more than 164,000 women worldwide demonstrated that the survival of patients with breast cancer may be associated with healthy eating, active living, and a healthy weight.469 These findings support the recommendation that all survivors of breast cancer eat a WFPBD, maintain a healthy weight, and get regular exercise.470 Research suggests that women who have a healthy weight and are physically active have a better chance of surviving breast cancer.
Healthy Eating: On the basis of the aforementioned evidence, women with a breast cancer diagnosis should enroll in a course on lifestyle management. This course should include advice from a WFPBD-trained lifestyle specialist. Consultation should include a discussion on a variety of issues outlined in the Sidebar: The Breast Cancer Wellness Index, including a focus on total health471and a WFPBD with a substantial reduction, and possibly complete elimination, of all animal-based foods. The dietary focus should emphasize the importance of fruits, vegetables, whole grains, and legumes as the basis for a healthy diet.472,473 Also included in a WFPBD is the elimination of energy-dense foods such as sugary drinks and processed foods high in added sugar, salt, and fat. These types of foods contain more calories per ounce and increase the risk of weight gain. Low-energy-dense foods, like those found in a WFPBD, allow patients to actually eat more food but consume fewer calories. A WFPBD results in decreased intake of foods that increase the risk of coronary artery disease474 and increased intake of foods that may prevent angiogenesis, or the growth of new blood vessels, to cancer cells.475
A large, multiple-database review (MEDLINE, Embase, and The Cochrane Library) to examine and to quantify the potential dose-response relation between fruit and vegetable consumption and the risk of all-cause, cardiovascular, and cancer mortality was reported in 2014.476 The researchers looked at prospective cohort studies that reported mortality risk estimates by levels of fruit and vegetable consumption. Sixteen prospective cohort studies were eligible in this meta-analysis, with follow-up periods ranging from 4.6 to 26 years in which there were 56,423 deaths (including 11,512 deaths caused by CVD and 16,817 due to cancer) among 833,234 participants. Higher consumption of fruits and vegetables was significantly associated with a lower risk of all-cause mortality. The researchers found that there was a threshold at 5 servings of fruits and vegetables per day, after which the risk of all-cause mortality was not further reduced. The results support current recommendations to increase consumption of fruits and vegetables to promote health and overall longevity. Other studies have shown that a diet rich in fruits and vegetables and low in fat lowers blood pressure and reduces the risk of stroke and type 2 DM.477-480 One meta-analysis of prospective cohort studies demonstrated that increased consumption of fruits and vegetables from fewer than 3 servings per day to more than 5 servings per day is related to a 17% reduction in CVD risk.479
In laboratory studies, many individual minerals, vitamins, and phytochemicals demonstrate anticancer effects, yet evidence suggests it is the synergy of compounds working together in the overall diet that offers the strongest cancer protection. No single food or food component can protect against cancer by itself, but strong evidence shows that a diet filled with a variety of plant foods (vegetables, fruits, whole grains, and beans) helps lower the risk of many cancers. A recent meta-analysis of prospective studies reported that a high intake of fruits and vegetables was associated with a reduction in the risk of breast cancer.481 Further data show that there may be an inverse association between dietary fiber intake and breast cancer risk.482 Finally, reducing dietary fat intake, with a modest influence on body weight, may improve relapse-free survival rates of patients with breast cancer receiving conventional cancer treatment.483
Fruits and vegetables contain large amounts of polyphenols. These nutrients have been shown in epidemiologic studies and meta-analyses to offer some protection against the development of cancers, CVD, and DM.484,485 Polyphenols may fight cancer by inhibiting carcinogenesis.486 For example, resveratrol, found in grapes, has been shown to inhibit the growth of a variety of cancer cells. Studies have shown that resveratrol has the potential to modulate all three stages of carcinogenesis (initiation, promotion, and progression), in both chemically and ultraviolet B-induced skin carcinogenesis in mice, as well as in various murine models of human cancers.487
A number of studies have demonstrated that consumption of polyphenols limits the incidence of coronary artery diseases.488Atherosclerotic lesions may be present and silent for decades before becoming active and causing cardiovascular events.488Polyphenols may be protective against CVDs by improving endothelial cell function, inhibiting oxidation of low-density lipoproteins, inhibiting platelet aggregation, and preventing macrophage activation and subsequent thrombosis.489,490
Although the association between breast cancer risk and dietary factors has long been identified, the complex relationship between obesity and breast cancer is poorly understood. Obesity in women presenting with breast cancer may be a marker of unhealthy eating and inactivity. However, recent data suggest that even more important than obesity status, women who eat at least five servings of fruits and vegetables per day have a survival advantage over women who do not.476
Active Living: A prospective observational study to determine whether physical activity among women with breast cancer decreases the risk of death caused by breast cancer compared with more sedentary women has demonstrated the relationship between breast cancer survival and physical activity.491 The study was based on responses from 2987 female registered nurses in the Nurses’ Health Study who were diagnosed with Stage I, II, or III breast cancer. Results showed that women who were inactive had a higher risk of death than women who were physically active. The greatest benefit occurred in women who performed the equivalent of walking 3 to 5 hours per week. The authors concluded that physical activity after a breast cancer diagnosis may reduce the risk of death; thus, women with breast cancer who follow physical activity recommendations may improve their survival.463
Additional studies have shown that women who increased physical activity after a breast cancer diagnosis reduce their overall risk of death by 45%, whereas women who decreased physical activity after diagnosis had a 4-fold greater risk of death.492,493 Other studies suggest that exercise after breast cancer diagnosis may improve overall quality of life494 and DFS.495 Healthy eating and active living interventions for women with breast cancer will require behavior change.496 Therefore, strategies for behavior change should be part of lifestyle management programs designed to improve survival in this population. Finally, physical activity has been shown to improve quality of life and balance of life after a breast cancer diagnosis.497
Emotional Resilience: Depression is a major public health problem and often is undiagnosed and untreated in women with breast cancer.498-500 Untreated, depression can cause amplification of physical symptoms, poor treatment adherence, and increased functional impairment.501,502 Physicians are now more aware of the importance of screening and treating depression while managing a particular chronic disease such as breast cancer.503,504 Important advances include routine depression screening at the time of breast cancer diagnosis,505 as well as early interventions and counseling specifically designed to treat depression in patients with cancer.506,507 Cognitive therapy appears to be particularly helpful in treating depression in patients with breast cancer.508 In addition, cognitive therapy may be used to help women with breast cancer achieve the biometric outcomes and weight loss goals associated with improved survival.509 Tamoxifen is commonly used in the treatment of women with breast cancer. As previously mentioned, certain antidepressants, including paroxetine, fluoxetine, and bupropion, may interfere with the metabolism of tamoxifen and should be avoided. Venlafaxine, desvenlafaxine, and mirtazapine do not appear to affect the metabolism of tamoxifen and may be considered the safer choice for the treatment of depression in patients with breast cancer who are receiving tamoxifen.116
Summary of Lifestyle Recommendations
Diet, physical activity, and weight play a major role in survival among patients with breast cancer.454 Looking at improving long-term survival in breast cancer encompasses a total-health strategy that includes a focus on healthy eating, active living, healthy weight, and emotional resilience.471
Five-year breast cancer survival rates have increased, and a total-health care plan will reduce a woman’s risk of cancer recurrence, new cancer formation, and CVD.457
HEALER is a total-health approach to wellness that includes treating the mind, body, and spirit of a patient with breast cancer. Our long-term goal is to help patients with breast cancer understand the importance of energy balance.510 By helping patients with breast cancer achieve a healthy weight and healthy biometrics, we can maximize their chances for long-term survival.