Olfactory changes among patients receiving chemotherapy Britt-Marie Bernhardson a, b, * , Carol Tishelman b, c, d , Lars Erik Rutqvist e a Department NVS, Division of Nursing, Karolinska Institutet, Stockholm, Sweden b R & D Unit, Stockholms Sjukhem Foundation, Stockholm, Sweden c Department LIME, Medical Management Centre, Karolinska Institutet, Stockholm, Sweden d School of Nursing, Midwifery and Social Work, University of Manchester, Manchester, UK e Department of Oncology and Pathology, Karolinska Institutet, Stockholm, Sweden Keywords: Olfaction Signs and symptoms Cancer Chemotherapy abstract 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, pseudohallucina- tions, or increased chemical sensitivity. Ó 2008 Published by Elsevier Ltd. Background Alterations in taste and smell sensitivity are known side effects of chemotherapy (Duffy et al., 2002) which impact patients’ daily life (Bernhardson et al., 2008; Cameron et al., 2003; Wickham et al., 1999). The senses of taste and smell closely interact during eating (Schiffman and Gatlin, 1993), with the flavor of food based on combined responses to both smell and taste. Taste and smell changes (TSCs) in non-chemotherapy contexts have been found to affect nutrition, as was made evident in the study by Hutton et al. (2007) of 66 patients with cancer in palliative units. We previously found that 340 of 518 patients receiving out- patient cancer chemotherapy reported taste changes, with 214 of these also reporting smell changes (Bernhardson et al., 2008). An additional 40 patients reported smell changes without taste changes. While different aspects of chemotherapy-related taste changes have been investigated (e.g. Berteretche et al., 2004; Epstein et al., 2002; Mattsson et al., 1992; Rhodes et al., 1994; Wickham et al., 1999), little is known about chemotherapy-related smell changes (SCs) that occur in the absence of taste changes. Rhodes et al. (1994) conducted one of the few studies describing smell changes during chemotherapy. They provide examples of how patients receiving chemotherapy could describe smell changes as unpleasant or as an increased awareness or sensitivity, with no patients reporting decreased sensitivity to smell. In a study of 50 patients receiving high-dose chemotherapy and allogeneic hema- topoietic cell transplantation, Epstein et al. (2002) found that among patients with cancer, 8% reported decreased sensitivity to odors, while 26% reported an increased sensitivity, and 24% reported other changes affecting sense of smell. Yakirevitch et al. (2005) hypothesized that high-dose cisplatinum might cause a reduced sense of smell since other senses such as hearing (Laurell and Jungnelius, 1990) and taste (Wickham et al., 1999) could diminish during treatment. They tested 21 patients using ‘‘Sniffin Sticks’’ and found a decrease in olfaction in one patient, while * Corresponding author. R&D Unit, Stockholms Sjukhem Foundation, Mariebergsgatan 22, 112 35 Stockholm, Sweden. Tel.: þ46 73 684 1147; fax: þ46 8 617 9333. E-mail address: britt-marie.bernhardson@ki.se (B.-M. Bernhardson). Contents lists available at ScienceDirect European Journal of Oncology Nursing journal homepage: www.elsevier.com/locate/ejon 1462-3889/$ – see front matter Ó 2008 Published by Elsevier Ltd. doi:10.1016/j.ejon.2008.10.002 European Journal of Oncology Nursing 13 (2009) 9–15