Nasal symptoms after radioiodine therapy: a rarely described side effect with similar frequency to lacrimal...

Salivary and lacrimal side effects of radioiodine therapy have been carefully described. However, nasal side effects are rarely described. The objective of this study was to document the frequency of nasal side effects in comparison to the already well-documented lacrimal side effects and to determine contributing risk factors.

A retrospective review of the medical records of 807 patients with differentiated thyroid cancer who received care at an academic medical center was conducted. Four hundred eleven patients who received treatment with radioactive iodine (RAI) were identified and included in the analysis. The frequency of both nasal and lacrimal side effects was ascertained. Factors that may have contributed to patients sustaining nasal damage after RAI therapy were also documented. These factors included radioactive iodine dose, method of preparation for receiving RAI therapy, and patient characteristics.

The mean dose of RAI administered was 109 mCi. Forty-three patients (10.5%) and 40 patients (9.7%) developed nasal and lacrimal side effects, respectively, following RAI treatment. The mean time of onset of nasal symptoms was 11 days, compared with 10 months for lacrimal symptoms. Radioiodine dose and body mass index were significantly positively and negatively correlated, respectively, with sustaining nasal side effects (p values of 0.04 and 0.01, respectively). Similarly, both RAI dose and body mass index were significantly correlated, positively and negatively, respectively, with sustaining lacrimal side effects (p values of 0.02 and 0.01). Preparation for treatment using a withdrawal protocol was associated with increased risk of both nasal and lacrimal side effects, compared with a recombinant human thyrotropin (rhTSH) protocol (p values of <0.01 and 0.01). The odds ratios (95% confidence interval [CI]) for nasal and lacrimal side effects with recombinant rhTSH preparation were 0.22 [0.11-0.44] and 0.37 [0.18-0.76], respectively. Instructions to maintain adequate hydration and development of lacrimal symptoms were only associated with nasal symptoms in unadjusted analyses.

Both nasal and lacrimal dysfunction occurred at an approximately 10% frequency. Although it cannot be determined whether acute nasal side effects are followed by long-term ramifications, these consequences of RAI could potentially add to the reasons to carefully evaluate the benefits and risks of RAI therapy on an individual basis.