Effect of stunning of diagnostic 131-iodine doses on ablative doses for differentiated thyroid cancer patient’s outcome

Abstract

Background: Thyroid stunning was defined as transient reduction of thyroid tissue uptake 131I (RAI-131) ablative dose after a diagnostic 131I dose that decreases the final absorbed dose in ablative therapy. Aim of the study: after following the proper precautions compare the response to the ablative dose given to patients with differentiated thyroid cancer with or without diagnostic radioactive iodine 131(RAI-131). Patients and methods: One hundred patients with differentiated thyroid cancer were included and divided into two groups: Group I, ablative dose of RAI-131according to their risk stratification without diagnostic dose and Group II, patients performing diagnostic whole body scan [5mCi] followed by ablative dose. Results: The current study have showed no significant associations between overall response in both groups and the different studied parameters except for the mean ablative dose of RAI-131 [r=0.9; P<0.001 and r=0.7, P<0.001 in group I and group II respectively]. Correlation matrix was used in all patients revealed that overall response was highly correlated with risk stratification; cervical nodal status and RAI-131 ablative dose [ P values <0.01; <0.01 and <0.01 respectively], while regression proved that the only predictor for response is the mean RAI-131 ablative dose. Conclusion: Following the proper precautions prevent stunning appearance after the diagnostic dose success rate to ablation will not be affected.