OBESITY IS associated with poor survival in patients with cancer, but when research is translated into survivorship care, obese and overweight patients can experience better outcomes, according to Karen Basen-Engquist, PhD, MPH, Professor of Behavioral Science and Director of the Center for Energy Balance in Cancer Prevention and Survivorship at The University of Texas MD Anderson Cancer Center in Houston. 

Karen Basen-Engquist, PhD, MPH

“Screening guidelines, testing guidelines, and survivorship care plans are all important, but we want to move toward making sure our survivors are living a healthy life, and lifestyle changes are critical to that,” she said at the 2018 Cancer Survivorship Symposium in Orlando.¹ 

Obesity and Cancer Outcomes 

THE BULK OF the evidence linking obesity and survivor outcomes lies in breast cancer. A meta-analysis of 82 studies, including over 200,000 women with breast cancer showed about a 41% decreased overall survival in obese patients compared to patients of normal weight.² Some reviews have demonstrated similar results in estrogen receptor–positive and estrogen receptor–negative breast cancers,³ and other research has shown an increased risk of cardiotoxicity in obese breast cancer survivors who receive anthracyclines.⁴ 

Data are limited in other cancer sites, but obesity is associated with poorer survival in endometrial, prostate, pancreatic, colorectal, ovarian, and some hematologic malignancies. Conversely, obesity is associated with better outcomes in certain disease sites, particularly those associated with more cachexia and wasting, ie, lung and esophageal cancers, but it is prudent to consider other factors potentially associated with survival—such as muscle mass and adiposity—in addition to body mass index (BMI), she noted. 

Effects of Weight Loss on Biomarkers, Quality of Life 

THE ENERGY TRIAL delivered a 2-year weight loss intervention to about 700 posttreatment breast cancer survivors.⁵ The intensive intervention offered weekly, dietitian-led, face-to-face counseling for 4 months, gradually tapering off to biweekly and finally monthly, with additional telephone and e-mail communication between sessions. 

“Screening guidelines, testing guidelines, and survivorship care plans are all important, but we want to move toward making sure our survivors are living a healthy life, and lifestyle changes are critical to that.”

— Karen Basen-Engquist, PhD, MPH

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“As expected with this kind of intensive intervention, they were successful at inducing weight loss in the intervention group,” Dr. Basen-Engquist said. Other promising outcomes of the trial included a significant difference in physical functioning between the intervention and control groups at 6 months (the control group experienced a decrease in functioning, whereas the intervention group did not) and fewer new medical conditions in the intervention group at 12 months. “So weight loss may be offsetting some other chronic disease problems,” she noted. 

The LEAN trial also focused on weight loss in breast cancer survivors.⁶ This 6-month intervention compared in-person counseling, telephone counseling, and usual care and found similar weight loss results in both the telephone and in-person arms. In the combined weight loss/counseling arms, there was a 30% decrease in C-reactive protein levels, and women who lost at least 5% of their baseline weight saw decreases in metabolic and inflammatory markers. 

The RENEW trial examined the effects of a strictly home-based diet and exercise program for overweight and obese breast, prostate, and colorectal cancer survivors over the age of 65.⁷ The year-long intervention offered tailored print information, 15 telephone coaching sessions, and materials and supplies that empowered patients to exercise at home (ie, pedometer, food and exercise journal, portion guide). In addition to resulting in modest weight loss, this intervention prevented a decline in physical functioning—as well as in all other quality-of-life measurements. 

In spite of the data we now have from these trials, there is still a gap in the literature regarding the relationship between weight loss and survival outcomes, according to Dr. Basen-Engquist. However, a number of large, ongoing randomized trials with disease endpoints (ie, BWEL, DIANA 5, SUCCESS C, LIVES, CHALLENGE, GAP 4) will hopefully answer the question of whether lifestyle changes can impact survival-related outcomes. 

“The term ‘obesity’ might seem neutral and clinical to us, but it’s not so neutral to our patients.”

— Karen Basen-Engquist, PhD, MPH

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Talking to Patients 

“IN TERMS OF what works for weight loss, I’m afraid the news is very boring. You have to eat less and exercise more,” Dr. Basen-Engquist said. 

A calorie-restricted diet (independent of macronutrient composition) should be recommended to overweight and obese patients. A higher protein diet may be beneficial to older individuals, as this helps prevent the loss of lean mass. Providing calorie targets can be helpful in keeping patients on track to lose 1 to 2 pounds per week, and weight-loss apps and activity trackers can offer tailored guidance based on weight and age. 

“It’s important to manage expectations,” she said. Although a patient might want to get back to an unrealistic weight, that is not always necessary to improve health. Sustained weight loss of as little as 3% to 5% can reduce the risk of type 2 diabetes and cardiovascular disease. Regular physical activity, resistance training for older individuals, and reducing sedentary behaviors and “screen time” are also vital, she added. 

When talking to patients about weight loss, providers should remain respectful and nonjudgmental and should start by discussing the health risks of excess weight. “The term ‘obesity’ might seem neutral and clinical to us, but it’s not so neutral to our patients,” she said. Patients tend to prefer terms like “weight” or “BMI” to “obesity” or “excess fat.” Be sensitive to cultural differences about weight, favorite foods, social norms and practices, and related issues, she added. 

Assess readiness, she urged. Not every patient is ready to engage in a weight-loss program, but many could still benefit from a discussion about the health benefits of losing weight. “Maybe they’re willing to make some small changes,” she said. “Small changes can pave the way for bigger changes later on.” 

Engage patients and discuss their typical eating, drinking, and physical activity habits, and if necessary, spread these questions out over the course of several visits. “Sometimes we need to query deeper into what our patients are experiencing and what their preferences and perceptions are,” she said. 

The Oncologist’s Influence 

IN A STUDY of endometrial cancer survivors,⁸ about half of those surveyed said they had received counseling from their primary care provider about weight loss, but only about a third reported receiving any counseling from their gynecologic oncologist. Of those counseled about weight loss from their primary care provider, 56% reported a weight loss attempt, but 100% of patients counseled by their oncologist reported a weight loss attempt. Notably, of those who did not receive counseling by either provider, none attempted weight loss. “This points to a teachable moment,” she said. 

She strongly encourages use of the ASCO Provider Toolkit (www.asco.org/practice-guidelines/cancer-care-initiatives/prevention-survivorship/obesity-cancer), which offers helpful instruments for both patients and providers, including obesity prevention and treatment guidelines as well as guidance on coverage and reimbursement for obesity prevention and treatment. 

With her colleagues, Dr. Basen-Engquist has helped to organize a National Cancer Policy Forum Workshop on translating physical activity and weight management research into practice. To download the workshop proceedings, visit www.nationalacademies.org/NCPF. ■

DISCLOSURE: Dr. Basen-Engquist reported no conflicts of interest. 

REFERENCES 

1. Basen-Engquist K: Obesity in the cancer survivor population. 2018 Cancer Survivorship Symposium. Presented February 16, 2018. 

2. Chan DS, Vieira AR, Aune D, et al: Body mass index and survival in women with breast cancer: Systematic literature review and meta-analysis of 82 follow-up studies. Ann Oncol 25:1901-1914, 2014. 

3. Niraula S, Ocana A, Ennis M, et al: Body size and breast cancer prognosis in relation to hormone receptor and menopausal status: A meta-analysis. Breast Cancer Res Treat 134:769-781, 2012. 

4. Guenancia C, Lefebvre A, Cardinale D, et al: Obesity as a risk factor for anthracyclines and trastuzumab cardiotoxicity in breast cancer: A systematic review and meta-analysis. J Clin Oncol 34:3157-3165, 2016. 

5. Rock CL, Flatt SW, Byers TE, et al: Results of the exercise and nutrition to enhance recovery and good health for you (ENERGY) trial: A behavioral weight loss intervention in overweight or obese breast cancer survivors. J Clin Oncol 33:3169-3176, 2015. 

6. Harrigan M, Cartmel B, Loftfield E, et al: randomized trial comparing telephone versus in-person weight loss counseling on body composition and circulating biomarkers in women treated for breast cancer: The lifestyle, exercise, and nutrition (LEAN) study. J Clin Oncol 34:669-676, 2016. 

7. Demark-Wahnefried W, Morey MC, Sloane R, et al: Reach out to enhance wellness home-based diet-exercise intervention promotes reproducible and sustainable long-term improvements in health behaviors, body weight, and physical functioning in older, overweight/obese cancer survivors. J Clin Oncol 30:2354-2361, 2012. 

8. Clark L, Ko E, Kernodle A, et al: Endometrial cancer survivors’ perceptions of provider obesity counseling and attempted behavior change: Are we seizing the moment? Int J Gynecol Cancer 26:318-324, 2016.