Olfactory function, olfactory bulb volume, and quality of life after radiotherapy for nasopharyngeal cancer

Objective: Radiotherapy (RT) is the standard treatment for nasopharyngeal cancer (NPC). Various advers effects may occur after RT. In this study, we aimed to evaluate the advers effects of RT on the olfactory bulb and olfactory function in patients with NPC and describe the impact of these effects on the patients' quality of life. Methods: We investigated 21 patients with NPC who received RT at least 12 months earlier, in addition to 21 age- and sex-matched healthy controls. The participants underwent a detailed nasoendoscopic ear, nose, and throat examination. All participants received orthonasal olfaction tests and a nasopharyngeal magnetic resonance imaging scan to measure olfactory bulb volume; in addition, they filled out a quality of life questionnaire. Results: There was a significant difference between the orthonasal olfactory test results of the patients and controls (p<0.05). The left and right side olfactory bulb volume values of the patients and controls were statistically similar (p=0.07). There was a significant difference between the quality of life questionnaire results of the patients and controls (p<0.05). Conclusion: Olfactory dysfunction was present in the majority of patients with NPC who received RT.