Effects of Radiation on Olfactory Function in Head and Neck Malignancy

Area of Science:

• Oncology
• Otorhinolaryngology
• Radiotherapy

Background:

• Olfactory dysfunction is a frequently overlooked adverse effect of radiation therapy.
• Head and neck malignancies often require radiation therapy (RT), potentially impacting sensory functions.

Purpose of the Study:

• To investigate the effect of RT on olfactory function in patients with head and neck malignancies (excluding nasal/nasopharyngeal tumors).
• To correlate olfactory changes with radiotherapy dose parameters.

Main Methods:

• A prospective observational study involving 34 participants undergoing RT for head and neck malignancies.
• Olfactory function was assessed using the Italian Nose Obstruction Symptom Evaluation (I-NOSE) scale and a modified I-Smell test (identification and threshold scores) at five time points.
• Radiotherapy dose parameters, including near maximum dose (D2%) and mean dose (Dmean) to the nasal cavity, were calculated and correlated with olfactory function.

Main Results:

• A significant decrease in olfactory identification, olfactory threshold, and combined olfactory scores was observed at the end of RT compared to pre-RT values.
• The Italian Nose Obstruction Symptom Evaluation (I-NOSE) score peaked at the end of RT and returned to baseline by 3-month follow-up.
• A significant but incomplete recovery of olfactory function was noted at the 3-month follow-up.

Conclusions:

• Radiation therapy leads to significant olfactory dysfunction and a temporary decline in quality of life related to olfaction.
• While olfactory function does not fully recover by 3 months post-RT, it does not adversely affect overall quality of life at this follow-up point.