May 1, 2012 — New guidelines aimed specifically at the 1 in 25 Americans who are cancer survivors have been issued by the American Cancer Society.
Maintaining a healthy weight, getting adequate physical activity, and eating a healthy diet can reduce the chance of recurrence and increase the likelihood of disease-free survival after a diagnosis, say the authors.
The guidelines were published online April 26 in CA: A Cancer Journal for Clinicians.
"While we've published previous reports outlining the evidence on the impact of nutrition and physical activity on cancer recurrence and survival, this is the first time the evidence has been strong enough to release formal guidelines for survivorship, as we've done for cancer prevention," coauthor Colleen Doyle, MS, RD, director of nutrition and physical activity at the American Cancer Society, said in a statement.
The most recent update of these previous reports was in 2006.
For the guidelines, a dozen experts in nutrition, physical activity, and cancer survivorship evaluated the scientific evidence and best clinical practices related to optimal nutrition and physical activity after the diagnosis of cancer.
The guidelines summarize "the findings of this expert panel, and is intended to present healthcare providers with the best possible information with which to help cancer survivors and their families make informed choices," Doyle said.
The power of physician advice...has been consistently demonstrated.
"Physicians and other healthcare providers have a unique opportunity to guide cancer patients toward optimal lifestyle choices, and thus can favorably influence the survivorship trajectory," the authors write.
"The power of physician advice in facilitating preventive health behavior has been consistently demonstrated," they note. As evidence, they cite a study of 450 breast cancer survivors in which "a simple recommendation" from an oncologist to exercise resulted in a significant increase in physical activity (Ann Behav Med. 2004;328:105-113).
One of the chief recommendations in the guidelines is to engage in regular physical activity. The aim should be at least 150 minutes per week of moderate-intensity activity and strength training twice a week.
Since the 2006 update, there has been a marked increase in the number of studies showing the benefit of exercise in patients who have completed the initial phase of therapy for their cancer, the authors note. Studies have shown a reduction in the risk for cancer recurrence and an improved overall survival in various cancers, including breast, colorectal, prostate, and ovarian, they add. Exercise has also been shown to increase quality of life, fatigue, psychosocial distress, depression, and self-esteem among cancers survivors.
There are a few particular issues that affect the ability of patients who are recovering from cancer treatment to exercise, the authors explain. For instance, they recommend that people with compromised immune function avoid public gyms and pools until their white blood cells return to safe levels. Patients who have had a bone marrow transplant are advised to avoid such exposures for a year after transplantation. In addition, patients who are undergoing radiotherapy can avoid irritation to irradiated skin by not swimming in chlorinated pools.
Another example is peripheral neuropathy, a common adverse effect from chemotherapy, and/or ataxia, which can affect the use of some limbs and/or balance. In these cases, a stationary bicycle is probably a better option than walking on a treadmill, the authors explain.
"The key point for cancer care professionals is that cancer survivors have unique motives, barriers, and preferences for physical activity," the authors write.
One of the other main recommendations focuses on achieving and maintaining a healthy weight, defined as a body mass index from 18 to 25 kg/m².
Many patients are overweight or obese when they are diagnosed with cancer, the authors note. There is "increasing evidence" that obesity is associated with an increased risk for cancer recurrence, and that it reduces the likelihood of disease-free and overall survival. After recovery from cancer treatment, intentional weight loss might be associated with health-related benefits, they explain. It is not proven that this will improve cancer-related outcomes, they note, but it is "likely probable."
At the other end of the spectrum, many cancer patients lose weight during their treatment; for example, patients with head and neck or lung cancer who have difficulty eating might be underweight or even malnourished. Fortified beverages and foods can be useful; in more extreme cases, tube feeding or intravenous parenteral nutrition might be needed.
The third main recommendation is to follow a diet that is rich is fruit, vegetables, and whole grains. Current public health recommendations in the United States are for adults to eat at least 2.0 to 3.0 cups of vegetables and 1.5 to 2.0 cups of fruit each day.
The authors cite a number of observational studies as evidence. Breast cancer survivors with a high intake of vegetables and whole grains showed a 43% reduction on overall mortality (J Clin Oncol. 2009;27:919-926). Another study of more than 1000 colorectal cancer survivors showed that a higher intake of red meat, processed meat, refined grains, and sugary desserts was a associated with a statistically significant increase in cancer recurrence and poorer overall survival (JAMA. 2007;298:754-764).
Some studies suggest that omega 3 fatty acids have specific benefits for cancer survivors, such as ameliorating cachexia, improving quality of life, and enhancing some forms of treatment, but the findings are not entirely consistent. Nevertheless, foods that are rich in omega 3 fatty acids (including fish and walnuts) should be encouraged, the authors note, because they have been associated with reductions in cardiovascular risk and overall mortality.
Recommendations regarding dietary supplements have changed. In the past, the use of standard vitamin and mineral supplements was recommended during and after treatment to ensure adequate nutrient intake. This practice has now "come under scrutiny," the authors note. "More recent data suggest that multivitamin supplements may actually increase the risk of mortality among healthy individuals, or at the very least, may not be helpful."
Many cancer survivors take supplements; recent studies estimate that 64% to 81% of cancer survivors take them, and that 14% to 32% started taking them after being diagnosed with cancer.
However, evidence from both observation studies and clinical trials suggests that dietary supplements are unlikely to improve prognosis or overall survival after the diagnosis of cancer, and they might actually increase mortality, the authors note.
The guidelines also discuss evidence that relates to specific cancer types, including breast, colorectal, endometrial, ovarian, lung, prostate, upper gastrointestinal, and head and neck cancers, and hematologic malignancies.
CA Cancer J Clin. Published online April 26, 2012. Abstract
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Cite this: First Formal Guidelines for Cancer Survivorship - Medscape - May 01, 2012.