Prevalence and characteristics of persistent taste and smell dysfunction after immune checkpoint inhibitor therapy for cancer

PURPOSE: To determine the prevalence and characteristics of persistent dysfunction of taste and smell, and salivary parameters in patients after completion of ICI therapy. METHODS: In this cross-sectional study, dysfunction in patients treated for cancer with ICIs was compared with dysfunction in caregivers. Subjective taste and smell dysfunction and their impact on life were evaluated using validated questionnaires. Objective taste and smell were assessed with taste strips and Sniffin' Sticks, and flow rate and biochemical composition of saliva were measured. RESULTS: A total of 50 patients and 51 caregivers were included. General characteristics of patients did not differ significantly from those of caregivers. Patients had received a median of 14 ICI cycles. The median time since the last ICI cycle was 3.7 years. Six patients (12%) reported mild subjective taste alterations and two (4%) moderate taste alterations, while two caregivers (4%) reported mild taste alterations. Patients scored lower on the appetite subscale and higher on sodium concentration compared to caregivers (respectively, p = 0.017 and p = 0.027). Objective taste and smell function, (un)stimulated saliva flow rates, and xerostomia did not significantly differ between both groups. CONCLUSIONS: These findings suggest that most patients do not experience persistent taste and smell dysfunction, and salivary changes after ICI treatment. However, a subgroup reports symptoms. As subjective experiences may not correspond with objective findings, clinicians should actively inquire about perceived sensory dysfunction as these can impact QoL. TRIAL REGISTRATION NUMBER: NCT06495008 / 2024-01-02.