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An Integrative Preventive Medicine Approach to Primary Cancer Prevention 

An Integrative Preventive Medicine Approach to Primary Cancer Prevention
Chapter:
An Integrative Preventive Medicine Approach to Primary Cancer Prevention
Author(s):

Heather Greenlee

, Kathleen Sanders

, and Zelda Moran

DOI:
10.1093/med/9780190241254.003.0015
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date: 30 November 2020

Introduction

There is a growing burden of cancer in the United States and globally, with the majority of new cases and deaths occurring in developing countries. As reported by the American Cancer Society, over the past 20 years, survival rates in the United States for most cancer types have improved and cancer mortality has decreased (Figures 15.1 and 15.2) but the number of new cancer cases worldwide is expected to double from 12.7 million new cases in 2008 to 21.4 million new cases in 2030. The increase in cancer incidence is due not only to aging populations and increased life expectancies but also to unhealthy lifestyle practices, environmental influences, and a lack of effective and accessible prevention strategies. It is estimated that approximately 20% of cancer diagnoses in the United States could be prevented by maintaining a healthy, whole food–based diet, engaging in regular physical activity, and committing to long-term weight management.1 Further, a large percentage of cancer cases could be prevented by avoiding vaccine-preventable infections, alcohol use, and tobacco use.1 The proportion of cancers caused by major risk factors differs by level of economic development (Figure 15.3). Overall, knowledge of current cancer prevention strategies is crucial for healthcare providers and patients worldwide. Given the increasing use of integrative medicine both nationally and internationally, it is important to understand the role of an integrative preventive medicine approach and which specific strategies may contribute to cancer prevention.

Figure 15.1 Trends in Age-Adjusted Cancer Death Rates* by Site, Males, US, 1930–2012

Figure 15.1 Trends in Age-Adjusted Cancer Death Rates* by Site, Males, US, 1930–2012

Reference 1.

Figure 15.2 Trends in Age-Adjusted Cancer Death Rates* by Site, Females, US, 1930–2012

Figure 15.2 Trends in Age-Adjusted Cancer Death Rates* by Site, Females, US, 1930–2012

Reference 1.

Figure 15.3 Proportion of Cancer Causes by Major Risk Factors and Level of Economic Development

Figure 15.3 Proportion of Cancer Causes by Major Risk Factors and Level of Economic Development

Reference 81.

Primary, Secondary and Tertiary Cancer Prevention

There are three levels of cancer prevention, each of which addresses a different stage of disease. Primary prevention seeks to prevent cancer occurrence by reducing an individual’s exposure to cancer risk factors. Proven primary cancer prevention strategies include vaccination to prevent viral infections that are known to be carcinogenic, prophylactic removal of at-risk organs among high-risk individuals, reducing environmental and workplace exposures, and promoting healthy lifestyle behaviors. Secondary cancer prevention aims to diagnose and treat precancerous and cancerous tissue as early as possible in order to either prevent the progression to cancer or to treat tumors at early stages when they are the most responsive to treatment. The primary form of secondary cancer prevention is screening for disease at regular intervals, such as mammography, colonoscopy, and pap smears. In order to be effective, cancer screening programs need to address geographic, cultural, health literacy and financial barriers to access, along with programs to increase public awareness and use of screening programs as the majority of patients with early-stage tumors are asymptomatic.2Tertiary cancer prevention, also known as cancer control, emphasizes reducing the risk of recurrence, metastases, and new primary cancers. Tertiary cancer prevention also includes reducing tumor-related complications, managing treatment-related side effects, and improving quality of life.2

Cancer Risk Factors

Increasing age is the largest risk factor for developing cancer,3 and other important risk factors include environmental exposures, health behaviors, genetics, and infectious agents. Risk factors can increase the risk for specific types of cancer and/or for cancer overall. Examples of environmental risk factors include exposure to radiation, sunlight, infectious agents, and dietary contaminants, such as mycotoxins. Common behavioral risk factors associated with increased risk of many types of cancer include tobacco use; being overweight or obese with a body mass index (BMI) over 25 kg/m2; a diet high in unhealthy fats and low in fruits, vegetables, and fiber; alcohol consumption over 1 drink per day for men and ½ a drink per day for women; and being sedentary with low levels of physical activity. Genetic risk factors specific to certain cancers include genetic mutations such as BRCA 1 and BRCA 2, which dramatically increase a woman’s chance of developing breast cancer; other hereditary cancer syndromes, such as Lynch syndrome, also known as hereditary nonpolyposis colorectal cancer, which increases risk of colon cancer as well as endometrial, ovarian, and other cancer in women; and Li Fraumeni syndrome, which can cause a range of cancers during childhood.4 There is also now a clear causal link established between specific infectious agents and specific cancers. Human papillomavirus (HPV) is strongly associated with cervical cancer, chronic infection with hepatitis B virus (HBV) or hepatitis C virus (HCV) is the strongest known risk factor for liver cancer, and a growing body of evidence suggests a link between human immunodeficiency virus (HIV) and a number of cancers, particularly cervical cancer, Kaposi sarcoma, and non-Hodgkin’s lymphoma.5,6

Role of Integrative Preventive Medicine Approaches to Cancer Prevention

A conventional cancer prevention approach begins with assessing cancer risk factors, which often includes age, gender, genetics, personal and family medical history, and occupational and lifestyle exposures. Clinical recommendations for interventions are based on the level of individual risk. In general, the majority of individuals can benefit from a healthful diet, physical activity, and vaccination to prevent infectious disease. Individuals at higher than average risk may receive recommendations for pharmacological chemoprevention and/or surgery to remove the susceptible organ. There is a growing interest by segments of both patients and clinicians to incorporate integrative medicine into cancer prevention strategies. The overarching goal of integrative medicine is to incorporate evidence-based and effective complementary therapies into effective conventional medical therapies in order to provide a more holistic and more effective approach to clinical care.7 As integrative medicine is an emerging field, especially within cancer prevention and cancer care, it is important to understand what is and is not known about the effectiveness of integrative medicine approaches to cancer prevention. Integrative therapies include biologic therapies and behavioral modifications such as dietary modifications, botanicals (herbs), vitamins and minerals, other dietary supplements, mind/body therapies, acupuncture, energy medicine, and non-Western systems of healing, most of which are not typically used as part of conventional medical practice. Integrative medicine refers to complementary, nonpharmacologic practices that are performed in conjunction with conventional treatments, while alternative medicine refers to practices used in lieu of standard treatments. This chapter focuses on the use of integrative medicine for primary cancer prevention.

Until fairly recently, the concept of primary cancer prevention was not widely accepted because there was limited evidence supporting the concept that carcinogenesis8 could be reversed or halted by any means. However, over the past few decades, clinical trials have shown that cancers can be prevented or postponed via vaccination, prophylactic surgery, chemoprevention, and behavioral modification such as smoking cessation and dietary change. For example, a trial showed that tamoxifen reduces the risk of developing breast cancer among women at higher than average risk,9 and that a low-fat diet reduces the likelihood of breast cancer recurrence among women with estrogen receptor-negative breast cancer.10 We currently have very limited clinical trial data on the effect of integrative approaches to primary cancer prevention, but this is a growing area of interest in basic science and clinical research. In order to understand the role of integrative therapies in cancer prevention, one must first understand the role and strength of evidence of conventional medical approaches to cancer prevention.

Effective Conventional Therapies for Cancer Prevention

We know that even in the absence of known risk factors, cancer is a common occurrence, and better means of primary prevention are needed. The current science also supports prophylactic surgery in some cases. There is an ongoing need for improved methods of early detection and intervention in cancer care.

Chemoprevention

For some cancers, conventional therapies used for cancer treatment are prescribed to high-risk individuals for cancer risk reduction. The most compelling evidence for this approach is in breast cancer. Among both pre- and postmenopausal women at high risk of breast cancer, 5 years of tamoxifen treatment reduces the risk of breast cancer11 as does 5 years of raloxifene for postmenopausal women at high risk of breast cancer.12

Prophylactic Organ Removal

Prophylactic organ removal has also been shown to be successful at reducing cancer risk, especially for breast and ovarian cancer. For women with a BRCA1 or BRCA2 genetic mutation, mastectomy substantially reduces the risk of breast cancer.13 Similarly, for women at high risk of ovarian cancer, a salpingo-oophorectomy substantially reduces the risk of both ovarian and breast cancer.14,15

Vaccinations and Infection Control

Viral infections are estimated to be responsible for 15% of cancers globally,16 including, but not limited to, liver, stomach, and cervical cancers.17 There are now effective vaccines to prevent some of these viral infections, with the implication that effective vaccination programs can prevent large numbers of cancer cases worldwide, especially in areas where these infections are common. Hepatitis B and C have been shown to be responsible for the majority of cirrhosis and liver cancer cases globally. While there is no vaccine for HCV, the HBV vaccine has been shown to be effective in preventing chronic hepatitis, which often progresses to liver cancer.18,19 The HPV vaccine was recently shown to preventing HPV infection with the HPV types that most commonly cause precancerous lesions and cervical, anal, and oropharyngeal cancer. The vaccine prevents infection with HPV 16 and 18, which have been shown to be responsible for 70% of cervical cancer cases worldwide.20 The HPV vaccine has now been proven as a safe method of risk reduction, and unprecedented in that it may be given to all sexually active females and males, regardless of their risk of transmitting or developing cervical cancer.21 While the HPV vaccine represents enormous potential for cancer prevention, there are significant public health challenges in implementing large-scale vaccination on a population level, especially for children.22

Infection with Helicobacter pylori, a bacteria that colonizes the stomach lining, has been identified as a major cause of gastric cancer. It is present in 30%–50% of the population, who are often asymptomatic. Common gastritis is often the first sign of gastric cancer, and cancer risk depends on the specific bacterial strain as well as specific host/microbe interactions, all of which make cost-efficient and effective screening for gastric cancer a major challenge. Gastric cancer is most common in areas with poor sanitation and low socioeconomic resources.23 Treatment using antibiotics to eradicate H. pylori may greatly reduce the risk of gastric cancer, but risk of cancer development depends on bacterial strains as well as certain host pathogen interactions, making effective screening and treatment of H. pylori difficult and complex on a large scale.23,24

Screening

The evidence for efficacy of cancer screening programs to prevent cancer deaths, particularly for breast and prostate, has shown mixed results. Meta-analysis of randomized-controlled trials of mammography screening, for example, has been shown to reduce mortality from breast cancer by 15%–20%.25 However, the degree of benefit from routine mammography screening is disputed, and there is not agreement among major guideline groups about the age at which routine mammography should begin. For example, the US Preventive Services Task Force (USPSTF) recommends biennial screening mammography for women aged 50 to 74 years,26 whereas the American Cancer Society recommends annual mammograms beginning at age 45 and biennial mammograms starting at age 55.27 Both groups state that women outside of these age ranges should be screened based on their individual personal and family history.

Lung cancer is the leading cause of cancer death among both men and women in the United States.28 Among adults aged 55 to 80 years with a 30-pack-year smoking history who currently smoke or have quit within the past 15 years, the USPSTF recommends annual screening for lung cancer with low-dose computed tomography.29 The USPSTF recommends that screening be discontinued once a person has not smoked for 15 years, or if the person develops a health problem that substantially limits life expectancy or the ability/willingness to have curative lung surgery.

The advantages and disadvantages of cancer screening programs continue to be researched, monitored, and hotly debated. It is crucial that healthcare providers and clinicians stay current on research findings and recommendations.30 The USPSTF guidelines are regularly updated and can be located at www.uspreventiveservicestaskforce.org.

Diet

There is a substantial literature based on observational data suggesting that people with healthier diets have a decreased risk of developing cancer.31 Specific protective dietary behaviors include high intake of fruits, vegetables, and other fiber sources, and low intake of alcohol, red meat, and processed meats. However, there are limited experimental data showing what dose and duration of these behaviors are needed to definitively reduce cancer risk. Thus far, the most compelling research on the use of diet for cancer prevention comes from two separate trials testing dietary change to prevent breast cancer recurrence.10,32 The trials had conflicting results. The Women’s Healthy Eating and Living (WHEL) trial tested a diet high in fruits and vegetables among breast cancer survivors and found no effect of the diet on breast cancer recurrence or survival. However, the Women’s Intervention Nutrition Study (WINS) study showed that a low-fat diet was associated with decreased risk of breast cancer recurrence among the subset of breast cancer survivors who had been diagnosed with estrogen receptor-negative tumors. The reason for the different findings in unclear; some researchers have suggested that the reason that the WINS study observed a difference was that the women who effectively lowered their fat intake also lost weight and that perhaps the improvement in survival was actually due to weight loss.

There is considerable research interest in specific bioactive phytochemical components in plant-based foods. Simply speaking, using color as an indicator of specific cancer-fighting phytochemicals has led to the idea of eating “a rainbow” of vegetables and fruits regularly to obtain the anticancer effect. There are a variety of cellular and molecular pathways that phytochemicals have been shown to affect, including immune modulation, growth factors, cancer cell viability, antioxidation, and the inflammatory process.33,34 Diet may further influence these pathways by altering DNA methylation, histone modification, and noncoding microRNA.35 For example, several human cohort studies have found association between cruciferous vegetables and decreased cancer risk. Cruciferous vegetables, including cauliflower, kale, cabbage, and broccoli sprouts, contain indole-3-carbinol (I3C), which has been shown to affect uncontrolled cellular growth and the viability of various types of cancer cells.36,37 In addition, cruciferous vegetables contain isothiocyanates, which have been shown to inhibit cancer development in animal models. Studies are investigating whether it is a specific dietary component that is needed to obtain a cancer prevention effect, or if it is the whole plant that is more effective. For example, in a rat study, neither indole-3 carbinol (I3C) alone nor isothiocyanates alone reduced tumor precursors.36 However, when rats were fed whole cruciferous vegetables, there was a reduction in colon cancer precursor cells. It is possible that the mix of bioactive compounds in whole cruciferous vegetables is needed to achieve the cancer prevention effects.

Lycopene and resveratrol are two other bioactive food components that have shown strong chemopreventive potential. Tomatoes contain carotenoids and polyphenols, with lycopene being a primary component of interest. Both clinical trials and observational studies have shown that lycopene may be an important active chemopreventive agent, especially for prostate cancer. Similar to the studies on cruciferous vegetables, studies suggest that intake of whole tomatoes may be more effective for cancer prevention compared to isolated lycopene or other bioactive components, and consumption of tomatoes cooked and combined with other foods has been shown to increase the body’s absorption of lycopene.38 Resveratrol is a polyphenol contained in berries, grapes, red wine, and peanuts. A phase I pilot study focused on colon cancer prevention demonstrated that resveratrol in combination with other bioactive components can inhibit the Wnt cellular pathway in vivo.39

The impact of dietary fiber on colon and small bowel cancer prevention has long been recognized and demonstrated in many epidemiologic and experimental studies, though there are also conflicting studies. Fiber seems to act both by decreasing the time that a carcinogen rests in the intestines and also by promoting a healthy gut flora. The interactions between dietary fiber, gut health, microbiota, body weight, and fat and protein intake is a very active area of cancer prevention research. Fiber as part of a whole-food approach to cancer prevention continues to be recommended by the American Cancer Society.40,41

Dietary fat has been associated with an increased risk of breast, colorectal, ovarian, prostate, and gallbladder cancers. While dietary fat is essential for energy production as well as cell and nervous system function, dietary fat also contributes to inflammation, which promotes carcinogenesis. There is evidence that healthy fats may be an important part of a cancer-preventive diet, distinct from trans fats and saturated animal fats. The balance between omega 6 and omega 3 fatty acids has been shown to be the most important distinction between healthy and unhealthy fats, with a low ratio (close to 1-1) of omega 6 to omega 3 fatty acids being considered ideal, and high ratios contributing to inflammatory and chronic diseases.42 This is an active area of research, and crucial to understanding both the potential health benefits of certain fatty foods, and in counseling patients on making long-term dietary changes. Examples of healthy fats include olives and olive oils, which contain lignans and peroxidation-resistant lipid oleic acid. It is suggested that high intake of healthy fats could explain why rates of major chronic diseases, such as cancer, are lower in people who follow a Mediterranean diet, which is high in olives and olive oil.43 Other healthy fat food sources include nuts, avocado, coconut oil, and sunflower oil. Studying the effect of fats on cancer risk has yielded mixed results, but remains an important area of research with many active ongoing cohort studies. The Women’s Health Initiative studied the effect of a low-fat diet on cancer risk and did not demonstrate an overall significant change in cancer rates, but women who entered the study with a very high fat diet and then substantially reduced their fat intake did have a reduced rate of subsequent breast cancer.44

There is a provocative and growing body of evidence suggesting that a Mediterranean dietary pattern has cancer prevention potential.45 The traditional Mediterranean diet meets the characteristics of an anticancer diet defined by the World Cancer Research Fund/American Institute for Cancer Research (WCRF/AICR). It is a diet rich in fruits, vegetables, whole grain bread and other cereals, beans, nuts, and seeds; high in olive oil as a key source of monounsaturated fat; low to moderate consumption of dairy, fish, poultry, and eggs; and low alcohol consumption, mainly in the form of wine. Observational study results suggest that high adherence to the Mediterranean diet is significantly associated with a reduced risk of cancer incidence and/or mortality.46 Provocatively, a recent randomized, clinical trial reported that the Mediterranean diet was effective in decreasing the incidence of primary breast cancer.47 The number of incident cancer events was small, and study results were planned secondary analyses of a trial testing the effect of the Mediterranean diet on cardiovascular outcome. Nevertheless, the results are provocative enough to warrant follow-up with a future larger trial of a Mediterranean diet examining incident breast cancer as the primary outcome of interest.

Observational studies have shown that vegetarian, vegan, or other diets low in meat or animal products are also associated with lower risk of a variety of cancers, but there are many confounding lifestyle factors among people who follow these diets making it difficult to interpret the observational study results. For example, people who follow these diets often have lower intake of alcohol and saturated fat, are more physically active, and are less likely to smoke. Therefore, given these important confounders, it is difficult to determine which specific factor or combination of factors is the most responsible for decreased cancer risk among vegans and vegetarians.

Food production processes are also considered in cancer prevention strategies. Interest in organically grown foods and animal feeds has increased in recent decades for many reasons, including a belief that these foods may lower the risk of cancer due to the absence of pesticides, herbicides, and other potentially carcinogenic compounds. While it is true that food can be a vehicle for contaminants and possibly harmful substances, whether conventionally grown foods are truly associated with increased cancer risk is unproven.48 On the other hand, it is well established that foods containing aflatoxins (e.g., grains and peanuts) contribute to the risk of liver cancer, and are most common in tropical countries with poor storage practices where grains are more susceptible to fungal contamination.49

Physical Activity

Physical activity has become a cancer prevention strategy of particular interest. Observational studies have also shown exercise to be protective against lung, kidney, endometrial, colon, breast, and possibly prostate cancer.50,51,52 To obtain optimal health benefits from physical activity, the 2008 Physical Activity Guidelines for Americans put forth by the US Surgeon General recommends that adults engage in at least 150 minutes of moderate-intensity aerobic physical activity or 75 minutes of vigorous-intensity physical activity, or an equivalent combination, each week and that children and adolescents be active for at least 60 minutes every day.5 People who are inactive and those who do not yet meet the guidelines are strongly encouraged to work toward this goal. Adults with disabilities who are unable to meet the guidelines should avoid inactivity and try to engage in regular physical activity according to their abilities.53

Possible mechanisms of action of physical activity and cancer risk include improved weight management, lower levels of hormones associated with increased risk of specific cancer (e.g., estrogen, insulin, and insulin-like growth factor), increased immune response, increased metabolism, and reduced gastrointestinal transit time, thereby decreasing the time of exposure to carcinogens in the digestive system. Regardless of the cancer prevention potential, physical activity has been shown to be important in improving quality of life for the general population and improve the prognosis of individuals diagnosed with cancer.54 Factors leading to sedentary behavior, how to decrease sedentary behavior, and the mechanisms by which sedentary behavior affects cancer risk are all active areas of research. For example, in two trials among colon cancer and prostate cancer survivors, a reduction in sedentary behavior was associated with a change in hormone levels as well in reducing fatigue and improving quality of life.55,56,57

It is important to recognize the need to individualize exercise prescriptions based on an individual’s physical ability, access to programs, financial constraints, and access to other resources. Motivational interviewing can be a useful tool for healthcare providers to assist and encourage people to make healthy behavioral changes.58 However, making simple behavioral changes is only the first step in life-long habit change.50 The surgeon general’s report strongly recognizes the need for community programs that support the ability to achieve and maintain lifelong change in exercise patterns. Public space dedicated for exercise and recreation in local parks or commonly used buildings such as schools, churches, and community centers is crucial to creating an environment where physical activity is feasible and accessible.59 An increasing amount of research is being conducted on the demand and design of behavioral support for increasing physical activity and other lifestyle behaviors. The use of smartphone apps and wearable devices may be useful for long-term habit change, but research needs to be conducted to identify whether or not these are effective at achieving and maintaining long-term behavior changes.60 A recent study among young adults with a BMI between 25 and 40 kg/m2 did not show an improvement in weight loss when the participants used a wearable device that monitors and provides feedback on physical activity.61 There is a need for larger and more rigorous studies on the potential of using wearable devices to motivate and monitor physical activity.

Weight Management

Obesity has been clearly shown to be a major risk factor for a number of cancers, specifically esophageal, pancreatic, colorectal, breast, endometrial, kidney, thyroid, and gallbladder cancers. There are several biological pathways linking obesity to carcinogenesis.54 First, fat tissue and fat cells produce excess amounts of hormones, such as estrogens, and adipokines, such as leptin, which stimulate cell proliferation. Both insulin and insulin-like-growth factor (IGF) are readily produced by fat cells, and both have been shown to promote tumor development. In addition, obesity is associated with chronic low levels of inflammation, which is known to promote carcinogenesis.59 Though genetics and epigenetics may play a role in the development of overweight and obesity, it is well established that a healthy diet and being physical active are both crucial to achieving and maintaining a healthy weight. National cancer prevention organizations have put forth similar recommendations for achieving and maintaining a healthy weight for cancer prevention. The American Cancer Society and the American Institute for Cancer Research both recommend that individuals achieve and maintain a healthy weight throughout life, and be as lean as possible throughout life without being underweight.62,63

Individuals often need structural support to effectively manage weight. Behavioral change programs such as Weight Watchers offer healthy diet information along with group support and a sense of community, and are a very effective way for many people to make and reach weight loss goals.64,65 When designing and recommending weight loss and weight maintenance programs, perceived benefit, gender, cultural factors, and access to resources need to be considered. Governmental policy on access to weight loss programs and related health insurance coverage affect a patient’s ability to make long-term behavioral changes. Recent policy changes related to the Affordable Care Act (ACA) have led to policies that consider obesity as a medically recognized disease and therefore provide coverage for both bariatric surgery and nutritional counseling. As of 2014, the ACA also prohibits the use of surcharges for obese patients as well as any consumer cost-sharing for obesity treatments including obesity screening and counseling.66

Dietary Supplements

The use of dietary supplements is very high in the United States, and is especially high among some populations at high risk of cancer.67 While dietary supplements are used for a wide variety of reasons, it is important to note that in most cases, there is insufficient evidence to conclude that they are protective against cancer, and some have even shown to increase the risk of some cancers.49,67 For example, large-scale clinical trials have been conducted to determine the effect of beta-carotene dietary supplements to prevent lung cancer in high-risk populations (i.e., smokers and asbestos workers) in the Alpha-Tocopherol, Beta Carotene Prevention Study (ATBC) and the Beta Carotene and Retinol Efficacy Trial (CARET).68,69 In contrast to the study hypotheses, both the ATBC and CARET trials69,70 found increased lung cancer risk among the populations that were expected to be protected. In the SELECT trial, vitamin E and selenium were tested for prostate cancer prevention; there was an increased risk of prostate cancer in participants taking selenium.71 It is important to note that effects may differ between dietary intake and supplemental intake of vitamins and minerals. Therefore, even if a vitamin in food is shown to be protective against cancer, research must be conducted to confirm that using supplements will also be effective.

At this time, dietary supplements are not recommended for preventing cancer. The US Preventive Services Task Force has stated that supplementation is unlikely to provide clinical benefits and may cause harm to some populations.72 To date, no dietary supplements have been shown to prevent cancer and a handful of supplements have been shown to increase risk. However, clinical trials are underway for several promising agents such as vitamin D, curcumin, and fish oil, and these important areas of research to monitor. The Natural Medicines database (www.naturalmedicines.therapeuticresearch.com) provides a comprehensive online resource for current information on the evidence on dietary supplements and other natural products.

Mind Body Medicine

There are a wide variety of types of approaches that fall under the rubric of mind body medicine, and while there is no evidence that it is directly effective for cancer prevention, it has been shown to be beneficial to quality of life, and may affect some physiologic pathways related to cancer prevention. Cognitive therapies include mindfulness-based stress reduction (MBSR), meditation, guided imagery, clinical hypnosis, and humor therapy. Sensory therapies include aromatherapy, massage, touch therapy, reiki, healing touch, therapeutic touch, music therapy, and creating a calm and/or beautiful space such as a room with a view or a healing garden. Expressive therapies include writing, journaling, art therapy, support groups, individual counseling, and psychotherapy. Physical therapies include dancing, yoga, and tai chi.73

The concept of mindfulness is being actively examined as a tool to promote the development of healthy eating habits, which has shown provocative results in a number of trials.74,75 Mindfulness-based programs for changing eating habits are an offshoot of the mindfulness-based stress management programs and use similar techniques for slowing down the eating process, improving food choices, and decreasing portion sizes. Mindfulness can also improve enjoyment of food, and programs are often offered in a group setting, which offers the extra social support that may facilitate long-term change.

Studies suggest that the regular practice of mind body medicine techniques affects functions of the neuroendocrine and immune systems in ways that may modify tumor development and/or progression, while also contributing to enhanced general well-being. When practiced regularly, mind body practices have been shown on MRI to positively impact areas of the brain associated with depression,76 and one cohort study showed that long-term meditation practice had a strong protective effect against high stress levels.77 For example, breast cancer patients who practiced relaxation and coping methods had lower serum cortisol levels and improved immune function.78,79 Music intervention programs have shown to improve pain, anxiety, fatigue, and general quality of life in cancer patients.80 Thus, while to date there is no evidence supporting mind body practices for cancer prevention, these practices are usually safe, often beneficial for mental health and quality of life, and usually low in cost.

Special Populations

Some integrative medicine therapies may have safety issues for special populations, including individuals with comorbidities and/or who are pediatric and geriatric patients. For very elderly or ill populations, physical activity may present risk of injury. Restorative yoga is an example of an exercise form that has been adapted for people who are very ill or physically challenged to move safely. Medications can interact with some natural products with serious side effects. Each patient should be evaluated individually before changes in physical activity, diet, or use of dietary supplements is recommended, and the healthcare provider should counsel the patient on the most effective and safe approach to cancer prevention and/or management.

Conclusion

Identifying and implementing effective cancer prevention strategies on a large population scale, whether they are conventional or integrative, has proven to be challenging. However, there is a growing body of evidence suggesting that there are effective cancer prevention strategies. Vaccinations for HBV and HPV are highly effective. There is a strong body of evidence supporting the role of major lifestyle factors to prevent a range of cancers, including smoking avoidance and cessation; no or reduced use of alcohol; a diet high in fruits and vegetables and low in fat, red meats, and processed meats; regular physical activity; and achieving and maintaining a healthy weight. A nascent but provocative body of literature suggests that stress management and mind body therapies clearly improve quality of life and may have the potential for cancer prevention. Though there is great interest by the general public on the use of dietary supplements for cancer prevention, no dietary supplements have been shown to effectively prevent cancer, while some have shown substantial harm. Therefore, individuals should be advised and coached on how to abstain from tobacco; meet daily recommendations for physical activity; eat a healthy diet high in whole grains, fruits, vegetables, and other sources of fiber, and healthy fats; consume alcohol only in moderation; and maintain a healthy weight. Individuals interested in the use of dietary supplements should be counseled about their known interactions, harms, and effects. And if applicable, individuals can be encouraged to engage in mind body practices that may improve their mood, sleep, and overall well-being, while they also may assist in sustaining lifestyle changes. An optimal preventive healthcare approach includes cancer prevention programs that integrate all evidence-based conventional and integrative treatment approaches and options.

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