At First-Ever Conference on Nutrition for Cancer Survivors, Researchers Vow to Find Needed Answers

American Institute for Cancer Research
Tuesday, 8 May 2001

For the very first time, cancer survivors today met with the nation's top cancer experts to discuss the need for useful dietary advice geared to the more than 8.5 million Americans who have undergone successful cancer treatment.

Marilyn Gentry, President of the American Institute for Cancer Research (AICR), announced that the Institute, known for its work in the area of diet and cancer prevention, will champion efforts to increase national awareness - and research funding - for nutritional strategies that may help prevent cancer recurrence and secondary cancers.

Speaking before the more than 300 cancer researchers, cancer survivors, policy makers, and members of the media gathered at the New York Academy of Medicine for AICR's "Nutrition After Cancer" conference, Gentry decried the current lack of reliable research on survivor issues in general and the area of diet in particular.

"Research has revealed convincing evidence that diet, exercise and weight management can influence the risk of first cancers," she said. "But little research has focused on how these same factors may help survivors keep healthy and free of disease. That's more than regrettable. That's downright frustrating. In fact, we have come here today to begin a process that will change all that."

Over the course of the daylong conference, survivors in attendance learned what science does -- and does not -- know about diet's ability to influence recurrence and secondary cancers. In return, scientists listened attentively to the many questions raised by survivors, and vowed to design new and better research efforts to find the answers.

Presentations and panels focused on all aspects of the diet-survivor connection. Much discussion revolved around ongoing efforts to identify the specific dietary and lifestyle choices that may influence risk of cancer recurrence, risk of secondary cancers, late effects of cancer treatment and overall quality of life.

Survivors Call for Answers to Questions and End to Confusion

Diana Dyer, a registered dietitian and three-time cancer survivor who has written widely on survivor issues, voiced many of the persistent questions that survivors have about diet after cancer. These questions, she said, have gone unanswered for too long and need to be studied more extensively.

"Cancer treatment brings about profound physical and emotional changes," she said. "Most survivors come out of this very difficult experience determined to do whatever it takes to stay healthy.

"What survivors want to know about diet and lifestyle is simple: What should I do? What, based on what we know right now, will give me the most cancer-protective bang for my buck?" Although survivors are "uniquely ready" to adopt advice about diet and exercise, she said, they are as yet hearing no coherent or consistent dietary message from the health community.

More specifically, Dyer identified two looming issues about which she is asked most often: Are soy foods safe? Are anti-oxidants potentially harmful during chemotherapy and radiation treatments?

"We want to see this research done," she said. "More than that, we want to see this research done well." The long-standing lack of peer-reviewed research on survivor issues, along with confusing and conflicting information in the popular press, means that many in the survivor community have come to rely on word of mouth, Dyer said.

"But these are life-and-death questions, and we can no longer afford to trust the promises of some neighbor's friend who's a furniture salesman and selling god knows what kind of supplement through a pyramid marketing scheme. We can't afford to, and we shouldn't have to."

More than anything else, Dyer said that she wanted to come away from the conference with "the sense that the questions raised here today are real questions, and they are being asked in a serious, sustained, and committed way. I would like us all to recognize that these issues deserve more national attention and more money, and acknowledge that they can no longer be minimized by physicians."

This last issue, Dyer admitted, is something of sore point. "In the short term, questions about diet and survivorship must be taken more seriously by medical practitioners," she said. "Because right now there are physicians telling their survivor patients to eat whatever they want, that it doesn't matter. When it comes to promoting healthy behaviors, it's the doctors who are on the front lines. They can, with just a few words of advice, do the most good, most immediately, for the most people."

Researchers Present "State of the Science," Urge More Investigation

One of the many cancer researchers who spoke at the AICR Nutrition After Cancer conference was Dr. Steven K. Clinton, an Associate Professor in the Department of Internal Medicine at Ohio State University. Dr. Clinton began his remarks by charting the tremendous progress that has been made in the prevention, early diagnosis and treatment of cancer in recent decades.

It was this very progress, Dr. Clinton said, that has led to the emergence of the entirely new area of medicine, research and social policy called cancer survivorship.

"The number of American cancer survivors now exceeds the annual number of new cancer cases and deaths," he said. "And as more and more people survive cancer, more and more practical questions arise."

Dr. Clinton described the unique set of obstacles faced by those researching diet's influence on cancer recurrence and other survivorship issues. Chief among these obstacles is a prevailing lack of national attention and, consequently, funding sources.

Without more established programs and sustained, comprehensive economic support, Clinton said, getting good research done on diet and survivorship remains a struggle. This is particularly unfortunate, he said, "because those undergoing cancer therapy and surviving cancer are demanding dietary advice they can use to help enhance their therapy and promote a healthy future."

On a personal level, he added, "making healthful, positive changes to one's diet provides a sense of self-empowerment that many survivors value highly."

Clinton characterized as "trivial" the amount of resources that have been invested thus far in research on nutritional strategies to make hormonal therapy, chemotherapy, radiation therapy and surgery more effective. This same lack of commitment is also the reason dietary guidelines tailored to survivors of specific cancer types are not yet available.

He then spoke to some of the specific questions raised by Dyer and other survivors in attendance, elucidating some of the complexities that must be considered when designing research studies that will attempt to find answers.

Questions have recently arisen around soy foods and antioxidants, for example, because cancer - and cancer treatment - can change some of the ways the body reacts to substances in these foods. Clinton reminded his audience that important questions remain. For example, foods that have been shown to be cancer-protective for individuals who have never had cancer may prove to offer greater or lesser protection for survivors.

In fact, some subjects in recent short-term trials with soy supplements experienced one kind of cellular behavior that may be associated with increased risk for breast cancer. In the case of antioxidants, research has shown that the same process for which these substances are prized (the so-called "scavenging" of potentially hazardous metabolic by-products, which has been linked to lower cancer risk) may actually increase the damage done by certain therapeutic agents.

Information on these and other issues, Clinton said, is still coming in, and will have to be weighed carefully before the science can speak more specifically. In the meantime, he referred survivors to the advice contained in AICR's Diet and Health Guidelines for Cancer Prevention (see below). Dr. Clinton concluded his remarks by lauding AICR for its "research programs that are committed to providing evidence-based knowledge to enhance survivorship," but stressed that more organizations, more researchers, and greater funding are desperately needed.

Best, Science-Based Dietary Advice for Survivors

Dr. David Heber, Chair and co-founder of the Center for Human Nutrition at UCLA, spoke later in the day about the practical, everyday steps that survivors can take that may help to reduce their risk of cancer. Variety and moderation are key, he said.

"The weight of evidence is convincing that a diet rich in a variety of vegetables, fruits, whole grains and beans helps reduce cancer risk among individuals who have never had cancer," he said. "There are no guarantees, of course. But these foods do contain potent vitamins, minerals and phytochemicals that seem to come to the body's aid to fight against and even halt the cancer process."

Although only a limited amount of research has specifically explored the role of diet among survivors, Dr. Heber and his colleagues at the conference believe it reasonable to assume that healthy dietary choices can significantly reduce the risk of recurrence and secondary cancers also.

"Eating a predominantly plant-based diet, drinking alcohol only in moderation or not at all, and avoiding tobacco completely - these are some of the simple, everyday steps that fortify the body's defenses. Such steps assume an even greater importance in the lives of survivors, whose systems may need a bit of extra help."

Dr. Heber then moved on to discuss questions about some of the "special cases" raised by Dr. Clinton and others, such as soy and antioxidants. If, he said, the changes brought about by cancer and cancer treatment can change how the body deals with those substances, is it possible that other foods that have been shown to be cancer-protective may offer no protection, or indeed be harmful, to the cancer survivor?

The answer, he said, lies in bearing in mind the two key dietary concepts cited most frequently by researchers over the course of the daylong conference: variety and moderation.

"Many different plant foods provide health benefits, and the best way to take advantage of that fact is to eat a large variety. Loading up on any one food, or food substance, is never advisable," said Dr. Heber. "But it's also important to keep in mind that the initial breast cancer trials that caused so much concern about soy were studying soy supplements, not soy foods."

Until further research can pin down the benefits and possible risks of soy consumption for survivors more clearly, Heber and his colleagues believe a balanced diet that includes a few servings of soy a week falls well inside the safe range. For soy pills and powders, however, the researchers advised caution. "These products can contain amounts of soy isoflavones far in excess of the amounts it is possible to get through the diet." He added that very little research has been done on the effects of such "mega-doses."

The latest advice on antioxidants during therapy also preaches moderation. Heber acknowledged that some cancer patients experience vitamin or mineral deficiencies which may be due to biological changes or to side effects of treatment that preclude a person from eating as much or as widely as they could.

Taking a multi-vitamin/mineral supplement can help such patients reach the Recommended Dietary Allowance (RDA) of important nutrients, he said. But Heber recommended patients avoid supplements that deliver doses of nutrients far in excess of the RDA, because such amounts may interfere with the beneficial effects of certain chemotherapies and/or radiation treatments.

"There remains much - too much -- we don't know about diet, nutrition and cancer recurrence," said Dr. Heber. "While we're waiting for more information, however, we do have some reliable, hard-won advice that will help to point our way."

For more information, or to contact American Institute for Cancer Research, see their website at: www.aicr.org