The thyroid gland is one of the most radiosensitive human organs. There are two major unwanted consequences from radiation to the thyroid in humans: hypothyroidism and neoplasia. In the system of dose limitation medical surveillance undoubtedly acquires obligations with regard to early tumor diagnosis (secondary prevention). On the basis of the risk coefficient of radioinduction of tumors established by international organizations, thyroidology should not be neglected. Following a wide range of doses of ionizing radiation, an increased risk of thyroid adenomas and nodules has been also observed in a variety of populations and settings, continuing for decades following exposure. Considerably less findings are available regarding functional thyroid disease including autoimmune diseases. In general, associations for these outcomes were fairly weak and significant radiation effect were most observed following high dose, particularly for hypothyroidism. Considerably less consistent findings are available regarding functional thyroid diseased including autoimmune diseases. The medical surveillance of exposed workers with thyroid pathology frequently involves delicate problems in particular concerning the differential diagnosis between benign and malignant nodules. In contrast to rare thyroid cancer, thyroid nodules are extremely common particularly among women. Thus, most thyroid nodules are benign, and it is important for a better outcome to identify those are likely to be malignant especially at an early stage. Therefore screening of all exposed workers is proposed since the beginning of their thyroid radiation exposure and an up to date diagnostic protocoI is discussed. As a consequence of this justified strategy of secondary prevention a huge amount of thyroid nodules, mostly benign, is found involving problems of management especially from the point of view of medical surveillance of radiation protection. In this paper the author: - 1) Discusses the issues and suggests an up to date approach to diagnosis and management of nodular and functional thyroid diseases - 2) Identifies conditions which representing particular problems require a more restrictive judgement of fitness - 3) Intends to demonstrate that the proposed diagnostic protocol conciliates with due economy providing the right balance between effectiveness and costs, the real requirement of medical surveillance, reducing as far as possible undesirable effects such as damage from excessive protection and patient/physician delay, which is extremely dangerous in the early diagnosis of tumors.
Nell’uomo due sono le maggiori conseguenze dell’esposizione della tiroide alle radiazioni ionizzanti: ipotiroidismo e neoplasia. La correlazione tra esposizione alle radiazioni ionizzanti e sviluppo di un carcinoma tiroidea è ormai ampiamente comprovata sia da evidenze radioepidemiologiche che dai risultati di indagini radiobiologiche condotte sugli animali. A seguito dell’esposizione a un ampio range di dosi di radiazioni ionizzanti si è anche osservato un aumentato rischio di adenomi e noduli tiroidei in una varietà di popolazioni. Ne deriva la necessità dell’attuazione, in occasione delle visite mediche preventiva e periodiche di radioprotezione medica, di programmi di oncoprevenzione secondaria per la quale viene in questo contesto proposto un aggiornato protocollo diagnostico e ne vengono discussi i criteri. Ne consegue inevitabilmente il confronto, più che con eventuali casi di tumori in eccesso dovuti all’irradiazione professionale, non solo con la cosiddetta patologia tumorale spontanea o naturale, ma soprattutto con le patologie tiroidee benigne, funzionali e/o nodulari, a seguito del rilievo delle quali, tenendo peraltro sempre conto del rischio espositivo professionale alle radiazioni ionizzanti, si configura sempre e comunque un problema di gestione, oggetto della presente trattazione. In merito alla formulazione del giudizio di idoneità, è sempre necessario valutare natura ed entità della tireopatia diagnosticata, confrontandola con il reale rischio lavorativo e tenendo presente la qualificazione professionale del soggetto in esame. La sorveglianza dovrà comunque risultare sempre vantaggiosa per il lavoratore e per la società in generale, in una realistica valutazione del rapporto rischi/benefici.
Keywords: benign thyroid diseases management; medical surveillance criteria; radiation protection; radiopathology; secondary prevention.
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