Gustatory and olfactory function in breast cancer patients

Loss of appetite is a common complaint in cancer patients. There is still no overall conclusion whether this symptom might be caused by distorted taste/smell function or by tumor byproducts. This knowledge would be important for adequate patient counseling as well as symptom relief. Several studies investigated taste function, but to our knowledge, only one studied olfactory function in cancer patients.

Sixty-nine breast cancer patients were investigated by a validated taste (taste strips) and smell test (Sniffin' Sticks) prior to chemotherapy.

Compared to normative data, breast cancer patients showed no significant difference in odor threshold, but better scores for odor identification and odor discrimination. For taste, breast cancer patients showed a significantly lower value for the quality sour compared to healthy controls only on left side of the tongue; there was no difference in the qualities sweet, salty, and bitter. An increase in tumor size was associated with a significant decrease in olfactory function, but not in gustatory function. Different histology or graduation of breast cancer, resection status, or metastasis to the lung and liver had no influence on taste and smell. There was no correlation between taste and smell to estrogen or progesterone receptor status. There was no correlation between smell and human epidermal growth factor receptor 2 (Her2 status), but there was a significant correlation between bitter taste and Her2 status.

Taste/smell did not seem substantially altered in breast cancer patients compared to normative data. Nevertheless, increasing tumor burden resulted in decreased olfactory function, but not in taste changes.