Role of Hyaluronic Acid and Chondroitin Sulphate in Protecting Urinary Epithelium in Patients Operated for Differentiated Thyroid Cancer Undergoing Ablation Therapy with Iodine-131

Background: It is not clear if the administration of iodine-131 in patients with differentiated thyroid cancers induces relevant cystitis and lower urinary tract infections (UTIs). The aim of this study was to evaluate the impact of oral administration of hyaluronic acid and chondroitin sulphate (HA&CS) on the frequency of UTIs induced by iodine-131. Methods: In this study, 166 female patients with a surgical diagnosis of differentiated thyroid cancer who were hospitalized in Sant ’Andrea Hospital of Rome to undergo the first cycle of therapy with iodine-131 for thyroid remnant ablation were evaluated. Sixty-one patients were treated with HA&CS for 8 days, and thirty-nine patients were treated with HA&CS for 17 days. Sixty-six patients were not treated with HA&CS and were used as control subjects. Patients underwent urinalysis at different time points: immediately before 131I therapy, two days later, and one week later. Patients were divided in six groups based on whether they received the treatment with HA&CS, its duration, and whether they developed a UTI: group A, n = 51 patients who did not receive HA&CS and did not develop UTI; group B1, n = 37 patients treated with HA&CS for 8 days and did not develop UTI; group B2, n = 29 patients treated with HA&CS for 17 days and did not develop UTI; group C, n = 15 patients who did not receive HA&CS and developed UTI; group D1, n = 24 patients treated with HA&CS for 8 days and developed UTI; group D2, n = 10 patients treated with HA&CS for 17 days and developed UTI. Results: The bacteria count, red blood cells and white blood cells did not change when group A was compared to both group B1 and group B2, while pH and epithelial cells showed a decrease over time when comparing group A and group B2 (p = 0.01 and p < 0.0001, respectively). Comparing group C with group D1 and group D2, patients who did not receive HA&CS (group C) showed a higher bacteria and epithelial cell count compared to those who were pre-treated with HA&CS. Conclusions: HA&CS could be an effective supportive therapy to prevent and mitigate UTIs in patients treated with 131I.