Sialochemical and oxidative analyses in radioactive I131-treated patients with thyroid carcinoma

I131 in relatively high doses has been shown in the past to cause damaging salivary effects and oral discomfort in patients. Although lower dosage is now widely accepted, I131 may still be the source of salivary damage over the long-term and subsequent harmful effects on both the oral cavity and the gastrointestinal tract, into which the saliva is swallowed. This study examined the effects of radioactive I131 on salivary gland activity, saliva composition and oxidative profile, and related oral discomfort complaints following thyroidectomy due to carcinoma of thyroid gland.

Out of 40 consenting female post-thyroidectomy patients, 23 (mean age 50+/-4 years old) were treated with I131 while 17 (mean age 46+/-4) were not. Whole saliva from all subjects was analyzed for antioxidant and biochemical composition and flow rate.

The salivary flow rates of both groups were similar but their composition differed considerably. Salivary superoxide dismutase enzyme (SOD), total protein, and albumin concentrations were significantly reduced in the treated patients by 40, 25, and 18% respectively (P<0.05), as were all other salivary antioxidants. Oral discomfort complaints were far more prevalent in the I131-treated patients.

I131-dependent damage to the salivary glands was evidenced by a broad spectrum of compositional alterations and oral complaints. Reduction in salivary antioxidant status, SOD enzyme, and the uric acid molecule leaves the oral cavity less protected against oxidative stress. This is the first report of radioactive I131 treatment being harmful to salivary glands due to compromised salivary compositional and oxidative profile and oral discomfort complaints.