Lorenzo Cohen, PhD
Alison Jefferies, BA, MEd
The ASCO Post’s Integrative Oncology series is intended to facilitate the availability of evidence-based information on integrative and complementary therapies sometimes used by patients with cancer. In this installment, Lorenzo Cohen, PhD, and Alison Jefferies, BA, MEd, summarize research findings and emphasize the importance of counseling patients to play an active role in improving their quality of life and well-being through lifestyle modifications for health.
Confronted with a cancer diagnosis and treatment, patients often ask doctors what they can do to alleviate symptom burden and prevent recurrence. With increasing evidence to support lifestyle modifications for health, there is a clear need to communicate with cancer patients about adopting such measures.
During and after treatment for cancer, patients often ask what they can do to improve their outcomes—to decrease the side effects of treatment, reduce the chance of disease recurrence, and increase long-term survival. Well-intentioned physicians and clinical staff may reassure patients there is nothing they need to do; through the best practices of treatment and follow-up care, cancer progression or recurrence will be caught early and new treatment approaches considered. A typical comment is: “You don’t need to worry. You can go back to leading your life as you did before cancer, and we’ll see you in 6 months.”
Unfortunately, this message removes an important aspect of control patients have over their cancer and the possibility of a second primary. It is also a lost opportunity for a teachable moment for patients and their loved ones, who typically accompany patients, to emphasize the importance of the link between lifestyle factors and cancer prevention and control and how to modify their risks. These same recommendations may also decrease other comorbidities patients often have, such as diabetes, hypertension, and cardiovascular disease.
Lifestyle Factors and Cancer
Although the evidence linking lifestyle factors to cancer is stronger in some areas than others, there is no debate that at least 50% of the most common cancers are attributable to lifestyle factors.1 These same factors also influence outcomes once someone has cancer.
These lifestyle factors can be categorized into physical and psychosocial categories: physical refers to diet, exercise/sedentary behavior, and exposure to environmental carcinogens and endocrine disruptors, as well as smoking, risky sexual behavior, and sun exposure; psychological refers to erosion of tight social support networks and chronic stress. These lifestyle factors have all independently been linked with cancer incidence and/or outcomes after a cancer diagnosis.1-3
With increasing evidence to support lifestyle modifications for health, there is a clear need to communicate with cancer patients about adopting such measures.— LORENZO COHEN, PhD, AND ALISON JEFFERIES, BA, MEd
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All these factors—diet, physical activity, environmental toxins, social support, and chronic stress—are linked with one or more key biologic hallmarks of cancer4 necessary for cancers to form, grow, and survive, such as tumor-promoting inflammation, avoiding immune destruction, inducing angiogenesis, and resisting cell death, to name a few.3,5-13 Furthermore, these lifestyle factors also interact with each other.
For example, we know that lack of social support makes it difficult to engage in healthy behaviors and manage chronic stress. Stress itself makes it difficult to engage in healthy behaviors and may lead to relapses in tobacco use,14 modified food choices,15 decreased beneficial effects of healthy foods,16 diminished interest in exercising,17 and disrupted sleep.18 (Sleep deprivation has also been linked with an increased cancer risk and cancer-specific and overall mortality.19,20) Sleep deprivation can modify food preferences21 as well as nutritional metabolic pathways,22 reduce energy for exercise, and may be linked with being overweight and obesity.20 Finally, exercise can influence stress,23 sleep,24 and metabolic processes.25
A More Comprehensive Approach
As the risk factors for developing cancer and those associated with better outcomes for people with cancer are multiple, modifying as many risk factors as possible simultaneously may result in greater risk reduction than modifying one or two risk factors alone. In fact, extensive epidemiologic research suggests the more guidelines followed for cancer prevention and control,26 the lower the risk of disease and cancer mortality.27 Clinical trials of individual lifestyle factors such as diet,28 exercise,29,30 and stress management31 have been found to improve clinical cancer outcomes. However, this research remains equivocal, as other studies have found limited benefit for recurrence of disease or survival outcomes when targeting modification of single lifestyle factors.32-34 Yet emerging data suggest there may be synergy between different lifestyle factors.35 For example, engaging in a healthy diet and being physically active together leads to a greater reduction in inflammatory markers relative to engaging in just one of the behaviors alone.36
Existing initial research of clinical trials focused on changing multiple lifestyle factors and behaviors shows evidence that this approach may, in fact, strengthen natural defenses, modify multiple cancer-specific biologic pathways, and have an impact on long-term outcomes.37-41 However, most previous lifestyle research modifies only one (eg, diet) or at the most two (eg, diet and exercise) behaviors, often resulting in limited effects.
Although thedata to date from randomized clinical trials of comprehensive lifestyle change are limited, it is important to weigh the risks of doing nothing, when it is known that people may be engaging in unhealthy habits that could lead to ill health and disease. Patients can still be counseled about some of the accepted and safe parameters to support healthy living. We need to guide patients in a direction we know is safe and would likely improve multiple other health indices and quality of life.
Modifying as many risk factors as possible simultaneously may result in greater risk reduction than modifying one or two risk factors alone.— LORENZO COHEN, PhD, AND ALISON JEFFERIES, BA, MEd
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The World Cancer Research Fund,42 the American Cancer Society,43 and the American Institute of Cancer Research (AICR)26 all have similar guidelines for cancer prevention, and they recommend cancer survivors follow these same guidelines. Here are the AICR guidelines: maintain a healthy weight; eat a primarily plant-based diet with a variety of vegetables, fruits, whole grains, and legumes such as beans; limit red meats and avoid processed meat; avoid sugary drinks and limit consumption of energy-dense foods; if consumed at all, limit alcohol to 1 drink a day for women and 2 for men; and be physically active for at least 30 minutes a day and limit sedentary behavior.26
When it comes to mind-body practices, there are many options, including the movement-based practices such as yoga, tai chi, or qigong and the hundreds to thousands of different meditation practices. Ultimately, the ideal program is one people are willing to do each day to reduce sympathetic nervous system activation and to create calm in their lives.
Finally, in the area of environmental factors, in the absence of clear evidence, it is ideal to follow the precautionary principle and to try to decrease exposure to endocrine disruptors and carcinogenic substances. There are a number of valuable resources to achieve this goal, including from the Environmental Working Group44 and the Breast Cancer Prevention Partners.45
If we truly want to win the “war” on cancer, we need to increase our focus on cancer prevention and start to implement lifestyle strategies we believe will reduce cancer risk and improve outcomes for those with cancer. It is time to modify the parting words cancer patients hear at the end of treatment—“See you in 6 months”—and use the encounter as a teachable moment to counsel them on the important role they can play in their future health and well-being.
DISCLOSURE: Dr. Cohen has received honoraria for certified continuing education from Teva and is an uncompensated consultant/advisor for Cancer Treatment Centers of America. Dr. Cohen and Ms. Jefferies are coauthors of Anticancer Living: Transform Your Life and Health With the Mix of Six.
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