Prophylactic prednisolone for the prevention of early and intermediate adverse effects of radioactive iodine therapy in patients with thyroid cancer: study protocol for a single-centre, phase II/III, randomized, double-blinded, placebo-controlled clinical trial

BACKGROUND: Radioactive iodine (RAI) therapy is the standard adjuvant treatment for differentiated thyroid cancer (i.e. papillary and follicular). RAI is associated with troublesome early, intermediate and late adverse effects. Although glucocorticoids are used for the management of these adverse effects, there is little evidence regarding the effectiveness of prophylactic glucocorticoids to prevent these complications. This trial will evaluate the efficacy of a short course of prophylactic glucocorticoids in the prevention of adverse effects of RAI treatment in patients with differentiated thyroid cancer. METHODS: A phase II/III, single-centre, randomized, double-blinded, placebo-controlled, parallel-arm clinical trial will be conducted. Patients with differentiated thyroid cancer who are referred to RAI therapy at the National Cancer Institute, Sri Lanka, will be randomized into two arms consisting of 200 patients each. The experimental group will receive prophylactic oral prednisolone 0.5 mg/kg and omeprazole 20 mg single dose 6 h before RAI therapy followed by oral prednisolone 0.5 mg/kg and omeprazole 20 mg daily for 3 days. The control group will receive oral placebo and omeprazole 20 mg single dose 6 h before RAI therapy followed by oral placebo and omeprazole 20 mg daily for 3 days. Clinically significant adverse effects assessed as related to RAI as well as prednisolone therapy and the quality of life parameters will be compared between the two groups. DISCUSSION: If proven beneficial, this intervention can be incorporated into the standard practice to reduce early and intermediate adverse effects of RAI for thyroid cancer with a potential improvement of quality of life. TRIAL REGISTRATION: Sri Lanka Clinical Trials Registry SLCTR/2020/009. Registered prospectively on 23 February 2020. Items of the WHO Trial Registration Data Set are provided in the supplementary file.