Possible protective effect of Zataria multiflora Boiss. on salivary glands in patients with differentiated thyroid carcinoma treated with radioiodine: A randomized, double-blind, placebo-controlled clinical trial

The standard treatment for differentiated thyroid carcinoma is post-surgical radioiodine ablation; however, salivary gland damage is prevalent. This study aimed to evaluate the efficacy of Zataria multiflora Boiss. (ZM) aerial part essential oil in protecting salivary glands from post-radioiodine therapy damage in differentiated thyroid cancer patients.

In this randomized clinical trial, 24 patients with differentiated thyroid cancer were randomly allocated to two groups: 11 patients in the ZM essential oil group and 13 in the placebo group. Patients in the intervention and placebo groups received 20 oral drops three times a day of ZM essential oil or placebo respectively, starting from one week before radioiodine therapy to 4 weeks afterward. Salivary gland function was assessed using scintigraphic parameters before and six months following radioiodine therapy.

Follow-up scintigraphy demonstrated significant decrease in parotid UI in the placebo group (P=0.032) while significant increase in UI (P=0.025) and EF (P=0.042) of the parotid was observed in the ZM group. Comparing changes in functional indices of salivary glands between the two groups after six months revealed significantly better function in parotid UI (P=0.005) and parotid EF (P=0.006) in the ZM group. Substantial damage to parotid UI was significantly less in the ZM group (P=0.044).

Results of this study demonstrated that administration of ZM essential oil to patients with differentiated thyroid cancer may protect the salivary glands from radioiodine injury.