NEW ORLEANS--Nutrition is a vital component of cancer management, yet nutritional assessment is still a very inexact science, Abby S. Bloch, PhD, RD, said at the 4th International Symposium on Nutrition and Cancer, sponsored by the Cancer Treatment Research Foundation and the Society for Nutritional Oncology Adjuvant Therapy.
"When I came to Memorial Sloan- Kettering 29 years ago, we were struggling with how to nutritionally assess the cancer patient. Today, there is still no universally acceptable or easily applicable assessment tool," Dr. Bloch said. "There is no accurate predictor of prognosis and no way to forecast the patients response to treatment."
A key question in the nutritional evaluation is: Where is the patient in the process of the disease? Throughout the continuum, the nutritional advice varies, and one must determine the need at any given time, she said.
For example, in a healthy patient who has risk factors for cancer, the nutritional need is a low-fat, high-fiber preventive diet. In the middle of cancer therapy, when patients may be struggling with anorexia and malnutrition, a high-fat intake is needed in order to make every calorie count. "Patients get conflicting information about diet and health, and we need to help them shift their priorities," Dr. Bloch said.
All cancer patients should be briefly screened and their risk and extent of nutritional depletion identified as accurately as possible. Weight status can be approached with anthropometrics; however, be aware, she warned, that there can be problems with calibration and methodology.
Obesity Gives False Illusion
Weight and weight management, in fact, are not necessarily key components of nutritional status, since obese patients can give a false illusion of nutritional well-being, she reminded the audience.
Body composition measures are used to quantify deep malnutrition, and a simple pinching together of the skin over the bone can give an estimation of the patients condition. Biochemical indices are not usable in the clinical setting, she said.
Diminished food intake is the most consistent problem in cancer patients; therefore, food intake should be assessed (though such information can be unreliable). Besides pain, swallowing difficulties, changes in taste, and early satiety, other problems that may interfere with eating, and should be evaluated, include lack of energy to shop for and prepare food, presence of depression, and side effects of medications, she said.
Metabolic changes are part of the cancer disease process as well as the therapy, and nutritional absorption can be affected, she added.
Functional status and other quality of life issues are key to the evaluation of the total patient, Dr. Bloch said. Patients should be queried about ambulation, basic self-care, dexterity, food preparation, and so forth. A few simple tests can help indicate strength, such as squeezing fingers or blowing at a piece of paper.
Finally, the clinician needs to ask, nonjudgmentally, about the patients use of complementary therapies such as medicinal herbs. "Most of your patients are either doing this or contemplating it, and they may be afraid to tell you," she said. "We use the terms integrative or complementary, not alternative, medicine. These are all part of patient management, and not separate choices."