and Clare McKindley2
(1)
Integrative Health, Cancer Prevention Center, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
(2)
Department of Clinical Nutrition, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
Chapter Overview
This chapter is designed to provide direction for health care providers looking for more education and training on the role nutrition plays in cancer risk reduction, specifically for cancer survivors. Nutrition guidelines from the most comprehensive research review are presented. Questions commonly asked by cancer survivors in a clinical setting are addressed. Because behavior change requires more than knowledge of guidelines, the chapter concludes with behavior change counseling tips and ideas on how to get survivors to apply the guidelines to their own plates. Finally, the chapter ends with a possible direction for nutrition guidelines in the future.
Introduction
Many cancer survivors proactively search for ways to reduce their risk of recurrence or metastasis. Lifestyle factors and behaviors, including nutrition, can play a role in reducing the risk of developing recurrent disease or a new primary cancer, as well as reducing comorbidities resulting from cancer treatment or preexisting health conditions. This chapter will focus on addressing the most common nutrition concerns expressed by survivors, from a clinical practice perspective.
Building the Recommendations
The most comprehensive research to date on the role of nutrition, food, and physical activity for cancer risk reduction is provided by the American Institute of Cancer Research/World Cancer Research Fund (AICR/WCRF 2006). AICR/WCRF provides a matrix that maps the associations between certain dietary and lifestyle components and the development of cancer at specific sites. AICR developed specific guidelines for cancer prevention and survivorship after analyzing more than 7,000 research articles. These guidelines use the terms convincing increased/decreased risk, probable increased/decreased risk, and limited–suggestive increased/decreased risk to define the strength of evidence that a dietary or lifestyle component is associated with cancer. The guidelines include eight quantifiable recommendations specific to cancer risk reduction and two special recommendations. One of these special recommendations specifically targets cancer survivors. Although limited research data are available from cancer survivor populations, AICR/WCRF recommends that survivors follow these guidelines to reduce the risk of developing recurrent disease or a new primary cancer.
The American Cancer Society (ACS) has published specific guidelines to help clarify the role of nutrition and physical activity after a cancer diagnosis. Revisions and updates to these guidelines occur approximately every 5 years, and the most recent update was published in 2012 (Rock et al. 2012). The guidelines contain four categories:
Best practices from diagnosis to recovery and living with advanced cancer
Guidelines for weight management, alcohol, and food safety
Information on specific cancer sites
Commonly asked questions and answers for cancer survivors
With these evidenced-based guidelines, health care providers can direct patients toward nutritional and lifestyle behaviors that can help reduce the risk of cancer.
Survivorship Challenges
According to the National Cancer Institute (2013), stress, depression, and anxiety are common during and after cancer therapy and can directly affect lifestyle behaviors, including nutritional intake. Directing survivors to support groups or physical activity groups, or using other appropriate methods, including encouraging survivors to work with mental health care professionals to aid in coping with symptoms and managing stress, may minimize negative behaviors or intake patterns that increase cancer risk.
According to the American Society of Clinical Oncology (2013), other latent side effects of cancer treatment may include the following:
Lymphedema as a result of surgical excision of lymph nodes or radiation to the lymph nodes
Heart disease or congestive heart failure as a result of the effects of radiation, the use of drugs such as doxorubicin (Adriamycin) or cyclophosphamide (Cytoxan, Clafen, or Neosar), or other cancer therapy
Difficulty breathing or change in lung function after treatment with chemotherapy, radiation to the chest, or specific drugs such as bleomycin (Blenoxane), carmustine (BiCNU, Becenum, or Carmubris), prednisone, dexamethasone, or methotrexate
Hormone alterations resulting from thyroidectomy, hysterectomy, steroid-induced hyperglycemia, or other changes to the endocrine or reproductive system
Osteoporosis secondary to chemotherapy, steroid medications, hormone therapy, or a sedentary lifestyle (high-risk population: survivors of breast cancer, prostate cancer, or childhood leukemia)
Cancer survivors are not immune to comorbidities such as obesity, hypercholesterolemia, cardiovascular disease, diabetes, and other disease conditions. Clinicians working with recipients of stem cell transplantation have observed increasing rates of cardiovascular disease, dyslipidemia, steroid-induced hyperglycemia, and obesity. Gynecologic and breast cancer clinicians have observed similarly increasing trends.
Weight Management
AICR and ACS emphasize weight management as a priority because overweight and obesity increase the risk of cancer and overall mortality. Total body and abdominal fatness have been shown to increase the risk of developing cancer at a number of sites. According to ACS, a 5–10% weight reduction is likely to produce significant health benefits when achieved through physical activity and healthy eating behaviors. Additional research is needed among survivor populations to identify the ideal frequency, type, duration, and intensity of physical activity needed for the minimum and maximum possible reduction in cancer risk. Additionally, further evidenced-based research is needed to determine which dietary behaviors lead to the minimum and maximum health benefits in survivor populations.
For assessing cancer risk related to weight and fat distribution, the following cost-effective and noninvasive tools are available: body mass index (BMI) and waist circumference. BMI is a number determined by a person’s weight and height that indicates total body fatness, calculated as weight (kg)/height (m)2. Many online BMI calculators are available, including one from the US Centers for Disease Control and Prevention (2011). An increased BMI (indicating overweight or obese; see Table 17.1) is associated with an increased risk for cancer at the following sites: colorectum, breast (in postmenopausal women), endometrium, esophagus, pancreas, gallbladder, kidney, and liver. However, BMI does have limitations. Overestimation of BMI is possible in highly muscular and lean individuals and underestimation of BMI is possible in elderly individuals or in those with muscular atrophy.
Table 17.1
Body mass index (BMI) weight status categories for adults older than 20 years
BMI | Weight status |
|---|---|
<18.5 | Underweight |
18.5–24.9 | Normal |
25–29.9 | Overweight |
≥30 | Obese |
Waist circumference is used to estimate abdominal fat. People with either a high waist circumference (>40 inches in men or >35 inches in women; Table 17.2) or an increase in waist circumference over time are at increased risk for pancreatic, colorectal, breast (in postmenopausal women), and endometrial cancers. Waist circumference is measured by placing a tape measure around the waist, just above hip bone, without pressing the tape into the skin.
Table 17.2
Health risk associated with waist circumference, for adults older than 20 years
Waist circumference, inches | ||
|---|---|---|
Health risk | Men | Women |
Low | ≤40 | ≤35 |
High | >40 | >35 |
In the past, waist-to-hip ratio was used to estimate excess abdominal fat. However, recent research indicates that waist circumference is a more accurate tool (AICR/WCRF 2006; see chapter 6.1.1.2: http://www.dietandcancerreport.org/cancer_resource_center/downloads/chapters/chapter_06.pdf).
Guidelines for the Role of Nutrition and Food in Cancer Risk Reduction
Plant-Based Diet
A cancer-fighting diet consists of plant-based foods but does not exclude food from animal sources (meats, eggs, and dairy). Vegetables, fruits, whole grains, and legumes contain fiber, nutrients, and phytochemicals that may reduce the risk of cancer at a number of sites, including the mouth, pharynx, larynx, esophagus, stomach, lung, pancreas, and prostate. An easy visual measurement to design a meal is to fill two-thirds of a plate with these plant-based foods. The remaining third of the plate is for lean protein from animal sources, such as fish, poultry, and red meats. Often, the recommended portion size for meats is equivalent to the size of a deck of cards. Non–animal-based protein sources include soy products, beans, peas, nuts, and seeds in combination with other plant foods such as whole grains.
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