It is well known that cancer patients undergoing chemotherapy and radiation therapy often experience nausea and loss of appetite. But until now, few researchers have looked into why this happens and what can be done to ensure that cancer patients maintain a healthy diet during treatment.
Researchers at the University of Alberta studying the effects of chemotherapy and radiation therapy on the senses report that most advanced cancer patients experience unique and persistent taste and smell abnormalities, believed to be a key factor in malnutrition and poor quality of life. The condition, known as chemosensory dysfunction, is believed to last long after patients have finished active chemotherapy or radiation therapy.
Taste distortion, heightened sensitivity to odours and a persistent bad taste in the mouth were the most common symptoms described by participants in the recent study conducted by Dr. Wendy Wismer and Dr. Vickie Baracos. However, Wismer says that every patient with chemosensory dysfunction has unique symptoms, and a diet tailored to her needs would likely improve quality of life.
"With taste and smell, and even with food consumption, we tend to draw broad conclusions and make sweeping recommendations," she says. For example, individuals with severe chemosensory dysfunction will often end up on a diet of soup or oral nutritional supplements such as Boost because their heightened or distorted senses make it difficult to eat much else.
"We're looking at how an altered sense of taste and smell affects the food you select. We argue that altered chemosensory perception is unique to the individual. In the same way that people need unique corrective lenses for their eyesight, patients need unique solutions for chemosensory distortion," Wismer explains.
Wismer and Baracos studied 66 patients with advanced cancer receiving palliative care and asked them to evaluate their own taste and smell functions using a validated questionnaire and three-day food diaries to assess their dietary intake. The vast majority--86 per cent of participants--reported some level of chemosensory abnormality. While this study focused on advanced cancer patients, Wismer believes the findings are relevant to any patient who has received chemotherapy or radiation therapy.
Further research will look at appropriate strategies to alleviate chemosensory dysfunction and explore how matching foods to an individual's unique chemosensory profile might help to prevent high rates of weight loss and malnutrition and improve quality of life.
The study is published in the February 2007 issue of the Journal of Pain and Symptom Management.
Materials provided by University of Alberta. Note: Content may be edited for style and length.
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