Chemical Senses in Cancer Patients

BACKGROUND: Cancer and its treatment therapies, such as chemotherapy and radiotherapy, have negative effects on taste and smell functions. It is easy to explain smell and taste dysfunctions when a cancer involves the peripheric end organs or neurologic pathways of smell and taste. However, it is difficult to understand how distortion in sensory perception develops as cancer progresses and cancer therapies are applied, because few studies on this subject have described heterogeneous oncological patient populations who are receiving different treatment regimens. METHODS: A literature review was performed about the chemical senses of the patients with various cancer types, and also about the possible mechanisms of taste and smell dysfunctions in cancer patients. RESULTS: Chemotherapy and radiotherapy may cause taste and smell alterations by destroying taste and olfactory receptor cells, creating alterations on the surfaces of cells and receptors as well as interrupting neural coding. The prevalence of taste dysfunctions in cancer patients has been reported to be up to 77%. Unlike taste dysfunction, diminished sensitivity of smell in cancer patients is described infrequently and the available literature contains some conflicting results for smell dysfunction in cancer patients. CONCLUSION: Further studies are needed on the loss of appetite in cancer patients, and specific treatments should be identified according to the pathologic mechanism responsible for anorexia and particularly for taste and smell dysfunctions. Because sufficient nutrition and energy intake can help patients overcome the cancer and its treatment-related complications.