Earlier this year, ASCO published the results of its new study on oncologists’ perceptions and practice behaviors regarding obesity, weight management, and related lifestyle factors in their patients both during and after cancer treatment.¹ The findings from the online survey of 971 oncology providers show how complex these issues are to address with patients and the barriers preventing oncologists from helping their patients implement behavioral changes to improve patients’ outcome and reduce their risk for cancer recurrence.

According to the survey results, although the vast majority of respondents (93%) agreed there is strong evidence showing that being overweight or obese affects cancer treatment outcomes and that addressing patients’ weight problems should be a standard part of cancer treatment (89%), 46% reported they rarely or never refer overweight patients or patients with obesity for weight management during active therapy. In addition, just 42% reported that they always or usually refer a patient to a dietitian to discuss healthy eating options.

When asked to identify the barriers to incorporating weight management and physical activity programs in the treatment of patients with cancer, most respondents (66%) cited a lack of time for counseling or to set up a referral; perceived patient resistance to behavioral interventions (73%); and a lack of available resources for referrals to interventions (63%). Respondents also overwhelmingly said that clinicians needed more training to adequately address these issues with patients (83%) and that interventions to implement changes in weight, diet, or activity should be conducted by other clinical staff with relevant expertise (84%).

Link Between Obesity and Cancer

In 2016, the International Agency for Research on Cancer published findings of its study showing sufficient evidence of a causal relationship between obesity and 13 types of cancer, including breast, colorectal, and multiple myeloma.² According to the National Institute of Diabetes and Digestive and Kidney Diseases, about two in three Americans are considered overweight or have obesity.³ If these trends continue, it is estimated that, by 2030, obesity will lead to more than 500,000 additional cases of cancer each year in the United States.⁴

The ASCO Post talked with Catherine M. Alfano, PhD, Vice President of Survivorship at the American Cancer Society (ACS) and coauthor of the ASCO study, about the challenges of treating patients with obesity; how barriers to reducing modifiable risk factors can be overcome; and the need to raise provider and public awareness of the benefits of weight management to prevent cancer and improve survival outcomes once cancer is diagnosed.

“Unfortunately, we live in an obesogenic environment, and everyone grapples with having enough time to be physically active and to eat well.”

— Catherine M. Alfano, PhD

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Making Weight Management Part of Clinical Care

Few respondents of the ASCO survey referred patients for weight management interventions or made referrals to support lifestyle changes, citing lack of time and available resources and perceived patient resistance to behavioral interventions. How can these barriers be overcome?

Many physicians struggle with these lifestyle behaviors themselves. Unfortunately, we live in an obesogenic environment, and everyone grapples with having enough time to be physically active and to eat well. An important result of the ASCO survey is that oncologists understand the important role weight management, physical activity, and a healthy diet play in cancer care and that addressing a patient’s weight should be a standard part of cancer treatment. That’s a huge change from 10 years ago, but there are barriers that make it difficult for oncologists to incorporate weight management and exercise programs into patients’ treatment plan. One major barrier is physicians’ perception that patients are resistant to wanting to hear about eating better and being active. The way to get around that resistance is to normalize the incorporation of weight management, diet, and exercise into the treatment discussion at the time of diagnosis.

For example, oncologists can say to patients, “We’re going to treat your cancer, and it’s important you adhere to the therapy we prescribe. It’s also important to take care of yourself by eating well and getting enough physical activity.” If you make lifestyle factors a standard part of oncology care, it will overcome patients’ resistance to making these lifestyle changes, because patients want to hear what they can do to help themselves have the best health and quality of life possible.

That is one critical barrier to overcome. The other major barrier to overcome is helping oncologists make patient referrals, so they can implement these lifestyle changes. Physicians can’t deliver those interventions, because many of them lack the time, education, and training in these areas, so we need to have other providers or programs in place to facilitate these patient referrals. For example, the hospital’s staff registered dietician or a psychologist who is trained in helping patients make behavioral changes can play a role.

“If you make lifestyle factors a standard part of oncology care, it will overcome patients’ resistance to making these lifestyle changes.”

— Catherine M. Alfano, PhD

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Improving Patients’ Quality of Life

Please talk about the impact obesity and being overweight have on cancer survivorship, including how they affect recovery from cancer treatment, increase the risk of cancer recurrence, and reduce quality of life.

Being overweight, sedentary, and having a poor diet make recovery from cancer more difficult and predispose patients to chronic and late effects from cancer treatment, such as fatigue and depression. Patients are more likely to have those problems and have them long term if they are unhealthy. Patients are also more likely to have comorbidities as a result of their weight, poor diet, and inactivity, including diabetes, heart disease, or arthritis, which compounds the problems caused by cancer.

Obesity is associated with poorer cancer outcomes and an increased risk of recurrence, as well as an increased risk of subsequent cancers. With the spiraling number of medications patients have to take for all of these comorbid conditions, in addition to the ones they take for their cancer, achieving a high quality of life becomes much more difficult and expensive. If we can help patients become healthier, we can prevent a reduction in their quality of life.

Educating Primary Care Physicians

Are the ACS and ASCO working together to raise awareness among primary care physicians about the connection between obesity and cancer occurrence/outcomes?

Several years ago, the ACS and ASCO jointly developed breast cancer survivorship care guidelines, specifically to help primary care clinicians and other health-care professionals provide comprehensive follow-up care for breast cancer survivors after treatment (www.cancer.org/health-care-professionals/american-cancer-society-survivorship-guidelines/breast-cancer-survivorship-care-guidelines.html).⁵ In addition to recommending regular surveillance for breast cancer recurrence and screening for new primary breast cancers, the guideline also recommends that survivorship clinicians counsel survivors on the importance of maintaining a healthy lifestyle, including consuming healthy foods, exercising, and maintaining a healthy weight.

GUEST EDITOR

Prevention in Oncology is guest edited by ­Jennifer A. Ligibel, MD, Chair of ASCO’s Energy Balance Working Group and a member of ASCO’s Cancer Survivorship and Cancer Prevention Committees. Dr. Ligibel is Director of the Leonard P. Zakim Center for Integrative Therapies at Dana-Farber Cancer Institute.

Each Prevention in Oncology column will address one of five areas in cancer prevention—alcohol use, obesity, tobacco use, vaccines to prevent cancer-causing infections, and germline genetics—with the goal of providing strategies to reduce the risk of cancer, as well as preventing cancer recurrence and second malignancy during cancer survivorship.

Now we need to help survivorship clinicians understand the importance of making timely and appropriate referrals for nutrition, exercise, and weight-management interventions. The problem is weight reduction programs are not usually reimbursable by health insurance companies. In the context of diabetes, the National Diabetes Prevention Program provides evidence-based solutions, including diet, exercise, and weight management, to reduce a person’s risk of developing type 2 diabetes, and it is usually covered by insurance.

We know that if we can prevent people with prediabetes from developing diabetes, we will not only improve their quality of life, we will drive down health-care costs as well. That model paves the way for what we have to do with cancer.

Raising Public Awareness

In ASCO’s 2017 National Cancer Opinion Survey, just 31% of respondents said that obesity is a risk factor for cancer.⁶ How can ASCO and the ACS raise public awareness about the importance of maintaining a healthy weight to reduce the risk of developing cancer?

We have to use both top-down and bottom-up approaches. We have to educate our providers about the importance of talking with their patients about their diet and exercise habits and making the appropriate referrals to support lifestyle changes. Moreover, we have to educate health-care consumers about why these interventions are important. (See the sidebar above on resources for both oncologists and cancer survivors about healthy lifestyle choices and the link between obesity and cancer.)

These conversations are difficult to have with patients because we don’t want to shame patients into thinking they developed cancer because of something they did to themselves. However, if we do not get the word out about the modifiable risk factors that could prevent cancer development, that would be a tragedy. 

DISCLOSURE: Dr. Alfano reported no conflicts of interest.

REFERENCES

1. Ligibel JA, Jones LW, Brewster AM, et al: Oncologists’ attitudes and practice of addressing diet, physical activity, and weight management with patients with cancer: Findings of an ASCO Survey of the Oncology Workforce. J Oncol Pract 15:e520-e528, 2019.

2. Lauby-Secretan B, Scoccinti C, Loomis D, et al: Body fatness and cancer—Viewpoint of the IARC Working Group. N Engl J Med 375:794-798, 2016.

3. National Institute of Diabetes and Digestive and Kidney Diseases: Overweight & Obesity Statistics. Available at www.niddk.nih.gov/health-information/health-statistics/overweight-obesity. Accessed November 4, 2019.

4. Wang YC, McPherson K, Marsh T, et al: Health and economic burden of the projected obesity trends in the USA and UK. Lancet 378:815-825, 2011.

5. Runowicz CD, Leach CR, Henry NL, et al: American Cancer Society/American Society of Clinical Oncology Breast Cancer Survivorship Care Guideline. CA Cancer J Clin 66:43-73, 2016.

6. National Cancer Opinion Survey: Prepared for American Society of Clinical Oncology, October 2017. Available at www.asco.org/sites/new-www.asco.org/files/content-files/research-and-progress/documents/ASCO-National-Cancer-Opinion-Survey-Results.pdf. Accessed November 4, 2019.