Radiation-Induced Rhinitis: Cytological and Olfactory Changes

Background: Oral mucositis is a well-known adverse event of radiotherapy (RT) for head and neck cancer (HNC). Its nasal counterpart, the radiation-induced rhinitis, is poorly studied and considered in clinical practice. Objective: The aim of this observational study was to evaluate acute cytological and olfactory alterations during RT and their correlation with RT doses. Methods: Ten patients who underwent RT for HNC, excluding tumors of the nasal cavities, were evaluated with nasal scraping for cytological examination, Sniffin’ Sticks test for olfactory assessment, and Nasal Obstruction Symptom Evaluation scale. The examinations were performed before (T0), at mid-course (T1), and at the end (T2) of RT. They were repeated 1 and 3 months after RT (T3 and T4). Mean dose (D _mean ) and near maximum dose (D _2% ) to nasal cavities and inferior turbinates were used for correlation analyses. Results: Radiation-induced rhinitis was present in 70% of patients at T2, and it was still observed in 40% of cases after 3 months. Although olfactory function remained within the normal range at the evaluated times, a significant decrease in odor threshold and discrimination was observed during RT, which returned to baseline levels after RT. Nasal cytology showed a radiation-induced rhinitis with neutrophils and sometimes bacteria. Mucous and squamous cell metaplasia appeared in 10% of patients. D _mean and D _2% to inferior turbinates were associated to neutrophilic rhinitis at T2, and D _2% to inferior turbinates was correlated to mucous cell metaplasia at T2. Conclusions: RT for HNC induces acute rhinitis that may persist after the completion of treatment and can affect patient’s quality of life. Nasal cytology can help to choose the best treatment on an individual basis.