Effects of radiotherapy on olfaction and nasal function in head and neck cancer patients

Radiotherapy (RT) is a major component of treatment in head and neck malignancies and often the radiation field includes the nasal cavity and olfactory cleft region. We aimed to assess olfaction, mucociliary clearance time and quality of life (QOL) before RT and during the course of radiotherapy.

This prospective, observational, cohort study was conducted over a period of 1 year. The olfactory function, mucociliary clearance and QOL of patients with primary head and neck cancers undergoing radiation therapy as part of treatment were assessed prior to radiotherapy and followed up serially up to 3 months after radiotherapy. A total of 21 patients were enrolled. Assessment was done using noninvasive tests for better compliance and ease of examination.

Among the 21 patients recruited, 18 completed radiotherapy and 13 were assessed 3 months post radiotherapy. Mean olfactory scores (including olfactory threshold and odor identification), using Connecticut Chemosensory Clinical Research Center (CCCRC) test, deteriorated significantly at the end of radiotherapy (p < 0.001) as compared to scores before irradiation. Subjective assessment of olfaction by Appetite, Hunger and Sensory perception (AHSP) questionnaire did not demonstrate significant impairment in nasal function (p < 0.319) although overall QOL significantly deteriorated (p 0.004). The mucociliary clearance time was prolonged in 72% of the patients at the end of radiotherapy.

Deterioration in olfactory function was found to occur during the course of radiotherapy with gradual improvement after 3 months. However, patients did not notice olfactory dysfunction subjectively. Mucociliary dysfunction persisted even after 3 months following radiation.