By ASTRO Journals Team
A recent Advances in Radiation Oncology article, Nutrition in Cancer: Evidence and Equality, examines the role of nutrition in cancer through the lens of social equity. Focusing on how diet affects cancer outcomes, particularly patients living in food priority areas (FPAs), the researchers sought to collect data at the human cellular level to advance understanding of the link between poor nutrition and cancer. Their research concentrated on four areas: nutritional intervention, synergy with definitive treatments, diet and long-term effects and how a lack of nutrient-dense foods contributes to outcomes. To learn more about this research, we reached out to the corresponding author Melissa A.L. Vyfhuis, MD, PhD, to answer a few questions.
Please summarize your study.
Our article attempts to answer the question: How does diet affect cancer outcomes? We tried to answer the question with as much data as possible, including human population level epidemiology down to cellular signaling. All in all, we found over 100 years of evidence that dietary intake can affect tumor development, may enhance treatment effects and may prevent symptoms associated with muscle wasting. Despite this, there are few clinical trials to demonstrate evidence-based recommendations. The highest-risk populations — those at high risk of nutritional deficits at baseline — may have the most to gain from such dietary interventions, but there are no studies to date.
What initially prompted you to pursue this study?
Historically, the primary focus of dietary intervention in oncology was caloric density. Understandably, oncologists are focused on the prevention of weight loss. Indeed, most clinical studies in humans aim to minimize treatment interruptions from manifestations of cachexia. However, if obesity, insulin resistance and metabolic syndrome account for major risk factors in tumorigenesis — and are major causes of death following completion of curative oncologic therapies — then perhaps the individual baseline should be taken into consideration. Our research demonstrates that nuance in dietary recommendations may be beneficial.
Looking at the bigger picture, how could your findings impact patient care? What do you see as the key practice-changing implications of the research?
Approximately one third of patients ask what they should eat prior to embarking on definitive cancer therapies. We see four separate and important questions that need further research to provide patients with the best answer. First, can nutritional intervention (micronutrient or macronutrient supplementation) mitigate or prevent cachexia and therefore help patients complete definitive therapies? Second, is there a possible treatment related effect whereby nutrition can synergize with definitive treatments to increase control or survival? Third, can a healthy diet mitigate the long-term side effects of definitive cancer therapies? Finally, to what extent are patients with the highest nutritional deficiencies at baseline adversely affected from their lack of access to nutrient dense foods?
Did anything about your findings surprise you?
We were surprised to find just how far back in time the original nutritional intervention studies go. Despite 100 years of animal data suggesting a treatment effect, we are still in need of large randomized trials across many disease sites and patient populations.
You point out that many studies have been published on the effects of living within an FPA and having higher incidences of various health issues like diabetes, hypertension, etc., but few studies have focused on cancer treatment and outcomes for patients living in FPAs. You then conclude that further research is needed to characterize the nutritional needs of cancer patients residing in FPAs and strategize how best to include them in future clinical trials. Why do you think this subject has not been studied as much as others regarding equity in health care, and what can cancer researchers do to include this population in future clinical trials?
I believe that this subject has not been studied as much because the prospective characterization of nutrition and its effect on cancer care is such a complicated, difficult task to begin unraveling, especially since other confounding factors can cloud the pictures such as access to care, social support and other psychosocial factors.
The recent addition of deregulated cellular energetics as an emerging hallmark of cancer highlights that the acceptance of the role in nutrition in cancer is also recent. We now hope to see this area of research grow rapidly.
What is the link between FPA and food deserts? Food deserts and poverty cannot be solved by health care practitioners alone, but what do you see as their role in decreasing the effects of living in these areas has on patients?
Patients living in FPAs (previously called food deserts) are at high risk of nutritional deficiencies because of lack of access; however, these zip codes can be very heterogenous. While community access to food cannot be solved by a health care professional, we hope to start a dialogue between oncology practitioners and patients. The end goal would be a discussion regarding the patient’s current diet, the recommended diet during and after a definitive cancer treatment and resources that can be used to bridge the gap. Hopefully, with these specific nutritional interventions, citizens at risk for poor eating habits can live longer, healthier lives after cancer care.
What steps can health care practitioners treating underserved populations living in FPAs take to improve nutrition, and therefore potentially improve outcomes, for patients?
We believe that asking patients about their current diet and access to nutritious foods is the best start.While future studies are needed, encouraging nutrient dense foods as opposed to calorically dense foods that are within each patient’s budget will likely be prudent. Also, having information on hand about resources available in the area (i.e. virtual pantry programs, church donations) to provide to patients can be helpful.
What are your next steps? Will you be pursuing further study?
Our next step is to better characterize our own patient population’s access to nutritious foods. In a prospective manner, we will gather data about our patient’s diets and economic means to determine how to best identify patients at the highest risk of nutritional deficits. We hope to begin to bridge the gap with those in the greatest need.
Read the full article, Nutrition in Cancer: Evidence and Equality in Advances in Radiation Oncology, ASTRO’s open-access journal.