Olfactory changes among patients receiving chemotherapy.

Taste and smell changes (TSCs) are known side effects of chemotherapy, but smell changes (SCs) in the absence of taste changes are understudied. This study aims to explore SCs occurring without taste changes during chemotherapy, to better understand the characteristics of such changes, and how these experiences affect patients in their daily lives. Data derives from a qualitative interview study and a cross-sectional survey of 518 patients, with all patients receiving out-patient cancer chemotherapy in Sweden. Case studies of three patients with SCs and the 8% of survey participants with SCs only are in focus. All 43 participants with exclusively SCs reported increased sensitivity to one or several odors, with no participants reporting decreased sensitivity. Those reporting SCs significantly more often reported weight gain than those reporting TSCs, with oral problems and appetite loss significantly less common in the SC group. There were no differences in reported nausea between SC and TSC groups, but nausea was more common in the SC group than in those without TSCs. The case study reports were linked to and discussed in relation to possible explanatory models for increased olfactory sensitivity. SCs increase during chemotherapy, were often unpredictable and led to emotional consequences. The participants all reported heightened sensitivity to one or several odors which could not fully be explained by the potential explanatory models of anticipatory nausea and vomiting, pseudohallucinations, or increased chemical sensitivity.