Stunning Is Not a Problem

Abstract

To stun has been defined in several ways. The Webster dictionary provides synonyms of “to make senseless,”, “to daze or stupefy,”, or “to shock deeply.”. The adjective form also means excellent or attractive. None of these accurately represent what is meant by “stunning” in relation to treatment of thyroid cancer. In this context, stunning means that a diagnostic prescribed activity of radioiodine (¹³¹I) can do sufficient damage to the thyroid that the follicular cells are incapable of trapping therapeutic prescribed activities of ¹³¹I. It is true that some of us were “stunned” when the concept was first presented. The early reports implied that there would be no uptake of the therapeutic ¹³¹I. Thus, when a pre-treatment diagnostic scan was compared to a post-therapy scan, the latter would show the absence of uptake at one or more sites previously seen on the pre-treatment diagnostic scan. Subsequently, the term was expanded to cover the possibility that the percentage of uptake of the therapeutic prescribed activity would be less than that of the prior diagnostic scintiscan, i.e., a quantitatively different finding. Lastly, the term “stunning” was expanded to include a worse outcome after treatment than when there was no diagnostic activity administered. Whether or not stunning actually occurs has divided opinions into two perspectives,; generating considerable debate. This section presents data arguing against the concept of stunning. However, it might be considered superfluous since many clinicians are treating patients with ¹³¹I without a prior diagnostic scan (although this is not the author’s recommendation), and those who obtain a diagnostic scan are more frequently employing ¹²³I that theoretically should not cause stunning. We always use this radionuclide for diagnostic whole-body scanning. The author also exhorts the reader to study carefully the details of published reports with attention to the quantity of ¹³¹I administered for the diagnostic scan, the percentage of uptake in thyroid tissue identified on scan (this is seldom available), and the delay between the administration of the diagnostic and therapeutic radioiodine (this also is often omitted in articles). Our group treats patients with a specified quantity of ¹³¹I that is determined from the diagnostic images, pathology, and Tg value and that specified quantity of ¹³¹I is ordered and administered on the same day as the diagnostic scan information is obtained. In several countries, there can be a delay of weeks or months between testing and treatment, and this alters the radiobiological effects of the former greatly. In Aa recent publication from Japan where patients treated with ¹³¹I for thyroid cancer have to be admitted to hospital and where there is a shortage of appropriate rooms, about one half of patients are not treated within 180 days of thyroidectomy.