Administración de radioyodo en cáncer diferenciado de tiroides bajo régimen hospitalario: a propósito de la implementación del aislamiento de radioyodoterapia en un hospital regional / Administration of radioiodine in differentiated thyroid cancer under a hospital regime: about the implementation of radioiodotherapy isolation in a regional hospital

Resumen Introducción El cáncer diferenciado de tiroides (CDT) presenta un aumento a nivel mundial. El uso selectivo de terapia con radioyodo (RAI) es un pilar de su tratamiento. Su efecto terapéutico se debe a la radiación beta, mientras que la gamma hace que sea necesaria la hospitalización para limitar la exposición de terceros. Objetivo Describir la seguridad de la administración de altas dosis de RAI en pacientes con CDT. Materiales y Método Estudio retrospectivo descriptivo. Se incluyó a todos los pacientes con diagnóstico de CDT que requirieron hospitalización para administración de RAI ≥ 30 mCi en el Hospital Regional de Talca (HRT) entre agosto-diciembre de 2018. Resultados Durante el período descrito 10 pacientes recibieron RAI bajo régimen hospitalario. La mediana de dosis de RAI administrada fue de 100 mCi (rango: 50-150 mCi). Todos los pacientes fueron manejados con asilamiento estricto. El promedio de hospitalización fue 28 horas, siendo dados de alta al reportar una tasa de dosis absorbida < 70 µSv/h a 1 metro. Se entregaron instrucciones al alta para minimizar el riesgo de irradiación o contaminación a terceras personas. Conclusiones Nuestro protocolo de administración de RAI permite tratar de manera segura a pacientes con CDT disminuyendo la exposición a radiación de terceros. Las salas de asilamiento de radioyodoterapia, podrían dar cobertura al 100% de la demanda de terapia con RAI en CDT a nivel local.

Introduction Differentiated thyroid cancer (CDT) presents an increase in global levels. The selective use of radioiodine therapy (RAI) is a pillar of its treatment. Its therapeutic effect is due to beta radiation, while gamma makes hospitalization necessary to limit exposure. Aim To describe the safety treated with RAI inpatients and the functioning of the radioactive isolation rooms of our center. Materials and Method Retrospective descriptive study. All patients diagnosed with CDT who required RAI therapy under a hospital regimen at the Regional Hospital of Talca (HRT) between August-December 2018 were included. Results During the period described, 10 patients were treated. The median dose of RAI administered was 100 mCi (range: 50-150 mCi). The average of hospitalization was 28 hours, being discharged when reporting an absorbed dose rate < 70 μSv/h at 1 meter, giving the patient instructions, so that they follow to minimize the risk of irradiation or contamination of people in their environment. Conclusions Our RAI administration protocol allows patients with CDT to be treated safely. The radioactive isolation rooms could cover 100% of the demand for RAI therapy in CDT at the local level.

Variación de dosis de radioyodo en pacientes con cáncer diferenciado de tiroides post implementación de guías ATA 2015 / Variation of radioiodine dose in patients with differentiated thyroid cancer after implementation of the ATA 2015 guidelines

Introducción: El cáncer diferenciado de tiroides (CDT), es actualmente la neoplasia endocrina más frecuente. Su tratamiento estándar es la resolución quirúrgica, asociado a ablación con radioyodo (RI) según la clasificación propuesta por la American Thyroid Association (ATA). Las indicaciones y dosis de este último, han ido variando en los últimos años según avanzan las investigaciones en este ámbito. Objetivo: En el siguiente estudio se compararon las dosis de RI utilizadas previo y posterior a la implementación de las últimas guías de la ATA. Materiales y métodos: Estudio retrospectivo observacional de 70 pacientes con diagnóstico de CDT del Hospital Clínico de la Universidad de Chile entre 2012 y 2017. Se agruparon los pacientes en dos cohortes, los operados entre los años 2012-2015 y los 2016-2017 clasificándolos según riesgo ATA, TNM y riesgo de recurrencia. Se consignaron las dosis de RI utilizadas y se compararon entre las cohortes. Análisis estadístico: Mann Whithney. Resultados: Al comparar la dosis de RI entre ambas cohortes, según TNM y riesgo ATA, se obtuvo los siguientes resultados: los pacientes T1b de la cohorte 2012-2015 presentaron dosis de RI significativamente mayores que los de la cohorte 2016-2017; también se evidenció que en pacientes N0 hubo una diferencia estadísticamente significativa, mostrando una tendencia a disminuir la dosis de RI; además, en los pacientes de la cohorte 2012-2015 con riesgo ATA intermedio, se obtuvo que las dosis de RI fueron significativamente mayores que las utilizadas en la cohorte 2016-2017. Conclusión: Se concluye que las variaciones de las dosis de RI utilizadas en pacientes con CDT en un hospital universitario van acorde a las recomendaciones internacionales actuales, particularmente la publicación de la guía ATA 2015, aplicándose radioablación con menor dosis de RI. Dado este cambio, se ha evidenciado igualdad de efectos con dosis menores de RI y consecuentemente menos efectos adversos.

Introduction: Differentiated thyroid cancer (CDT) is currently the most frequent endocrine neoplasia. Its standard of care is surgical treatment, associated with radioiodine ablation (IR) according to the classification proposed by the American Thyroid Association (ATA). The indications and doses of the latter have changed in recent years as research in this area advances. Objective: In the following study, the doses of IR used before and after the implementation of the latest ATA guidelines were compared. Materials and methods: Retrospective observational study of 70 patients with a diagnosis of CDT from the Clinical Hospital of the University of Chile between 2012 and 2017. Patients were grouped into two cohorts, those surgically intervened between the years 2012-2015 and 2016-2017, classifying them according to ATA risk, TNM and recurrence risk. The IR doses used were reported and compared between the cohorts. Statistical analysis: Mann Whithney. Results: When comparing the IR dose between both cohorts, according to TNM and ATA risk, the following results were obtained: T1b patients in the 2012-2015 cohort had significantly higher IR doses than those in the 2016-2017 cohort; It was also evidenced that N0 patients showed a statistically significant tendency to decrease the IR dose; In addition, the 2012-2015 cohort with intermediate ATA risk, revealed IR doses significantly higher than those used in the 2016-2017 cohort. Conclusion: It is concluded that the variations in IR doses, used in patients with CDT in a university hospital, are in accordance with current international recommendations, particularly the publication of the ATA 2015 guidelines, applying radioablation with a lower dose of IR. Given this change, equality of effects has been evidenced with lower doses of IR and consequently fewer adverse effects.

Carcinoma papilar de tiroides, variante de células altas: reporte de caso / Papillary thyroid carcinoma, high cell variant: case report

El carcinoma papilar de tiroides variante de células altas, descrito en 1976 por Hawk y Hazard, representa el 1% de los carcinomas diferenciados, siendo más agresivo e invasivo que la forma clásica y 80% de los casos se asocia con mutación B-RAF. Se presenta el caso de una mujer de 49 años con tumoración dolorosa en cara anterolateral de cuello, que tuvo un crecimiento rápido, disfonía y lateralización del cuello a izquierda. En la ecografía de tiroides se vio en el lóbulo derecho un voluminoso nódulo mixto, predominantemente sólido, hipoecogénico, con micro calcificaciones, sin separación del plano graso con los músculos infra hioideos. Se realizó punción con aguja fina que resultó Bethesda VI. En valoración pre quirúrgico se encontró la parálisis de cuerda vocal derecha. Se realizó tiroidectomía total con vaciamiento central y lateral derecho. El estudio anatomo-patológico reportó un carcinoma papilar de tiroides variante de células altas de 33 x 40 x 27 mm en lóbulo derecho que contacta con la tinta china, evade la cápsula y presenta invasión perineural. Ocho ganglios de 18 analizados fueron metastásicos en el compartimento VI. Posteriormente se realizó rastreo corporal total con una dosis mínima de I131 y luego se administró 150 mCi de I131. El carcinoma papilar de tiroides, variante de células altas puede presentarse inicialmente con el compromiso locorregional y su correcto diagnóstico tiene implicancia en el pronóstico y su manejo terapéutico. Debemos pensar en variantes agresivas cuando al inicio ya encontramos elementos sugestivos de extensión extratiroidea, como en este reporte.

High-cell variant papillary thyroid carcinoma, described in 1976 by Hawk and Hazard, represents 1% of differentiated carcinomas, being more aggressive and invasive than the classic form, and 80% of cases is associated with a B-RAF mutation. We present the case of a 49-year-old woman with a painful tumor on the anterolateral side of the neck, who had rapid growth, dysphonia and lateralization of the neck to the left. On thyroid ultrasound, a voluminous mixed node, predominantly solid, hypo echogenic, with micro calcifications, without separation of the fat plane with the infrahyoid muscles, was seen in the right lobe. Fine needle puncture was performed, resulting in Bethesda VI. In pre-surgical evaluation, right vocal cord paralysis was found. Total thyroidectomy was performed with central and right lateral emptying. The pathology study reported a 33 x 40 x 27 mm high cell variant papillary thyroid carcinoma in the right lobe that contacted with the Chinese ink, evaded the capsule and presented perineural invasion. Eight lymph nodes out of 18 analyzed were metastatic in compartment VI. Subsequently, a total body scan wasperformed with a minimum dose of I131 and then 150 mCi of I131 was administered. Papillary thyroid carcinoma, a high-cell variant, may initially present with loco regional involvement and its correct diagnosis has implications for prognosis and therapeutic management. We must think of aggressive variants when at the beginning we already found elements suggestive of extra thyroid extension, as in this report.

In properly selected patients with differentiated thyroid cancer, antithyroglobulin antibodies decline after thyroidectomy and their sole presence should not be an indication for radioiodine ablation

ABSTRACT Objective Our objective was to evaluate the trend of antithyroglobulin antibodies (TgAb) during follow-up of patients with differentiated thyroid cancer (DTC) treated without RAI, as well as their role in the risk of recurrence. Subjects and methods This was a prospective, descriptive study. A total of 152 consecutive patients with DTC treated in a single institution undergoing total thyroidectomy without RAI and followed for a median of 2.3 years (0.5-10.3) were divided in two groups: TgAb(-) (n = 111) and TgAb(+) (n = 41). Patients were classified according to AJCC 7th and 8th editions, as well as to their risk of recurrence and response to treatment categories. Results Both groups, TgAb(-) and TgAb(+), were similar regarding patient and tumor characteristics. At the end of follow-up, 90 (59.2%), 57 (37.5%), 3 (2%) and 2 (1.3%) patients achieved excellent, indeterminate, biochemically incomplete and structurally incomplete response, respectively. The risk of structural recurrence was similar in both groups (TgAb[-] 0.9% vs. TgAb[+] 2.4%, p = 0.46). In the TgAb(+) group, TgAb became negative in 10 (24.4%), decreased ≥ 50% without negativization in 25 (60.9%), decreased < 50% in 4 (9.8%) and remained stable or increased in 2 (4.9%) cases. The only incomplete structural response had increasing TgAb during follow-up. Conclusions In properly selected patients with DTC, TgAb concentration immediately after total thyroidectomy should not mandate RAI ablation, and their trend during follow-up may impact the risk of recurrence.

Tratamiento con radioyodo endovenoso y estimulación con TSH recombinante humana en paciente con cáncer de tiroides extenso: caso clínico / Intravenous radioiodine and recombinant human TSH in a patient with extensive thyroid cáncer: report of one case

Abstract: We report a 72-years-old male patient with extensive differentiated thyroid cancer (DTC), who required a tracheostomy and gastrostomy. Considering his clinical condition, risk of aspiration and management of the ostomies, radioiodine (131I) was administered intravenously, using recombinant human thyrotropin (rhTSH) and levothyroxine. The procedure was successful, both clinically and in terms of radioprotection.

Potential role of sorafenib as neoadjuvant therapy in unresectable papillary thyroid cancer

Summary Total thyroidectomy, radioiodine (RAI) therapy, and TSH suppression are the mainstay treatment for differentiated thyroid carcinomas (DTCs). Treatments for metastatic disease include surgery, external-beam radiotherapy, RAI, and kinase inhibitors for progressive iodine-refractory disease. Unresectable locoregional disease remains a challenge, as standard therapy with RAI becomes unfeasible. We report a case of a young patient who presented with unresectable papillary thyroid carcinoma (PTC), and treatment with sorafenib allowed total thyroidectomy and RAI therapy. A 20-year-old male presented with severe respiratory distress due to an enlarging cervical mass. Imaging studies revealed an enlarged multinodular thyroid gland, extensive cervical adenopathy, severe tracheal stenosis, and pulmonary micronodules. He required an urgent surgical intervention and underwent tracheostomy and partial left neck dissection, as the disease was deemed unresectable; pathology revealed PTC. Treatment with sorafenib was initiated, resulting in significant tumor reduction allowing near total thyroidectomy and bilateral neck dissection. Postoperatively, the patient underwent radiotherapy for residual tracheal lesion, followed by RAI therapy for avid cervical and pulmonary disease. The patient's disease remains stable 4 years after diagnosis. Sorafenib has been approved for progressive RAI-refractory metastatic DTCs. In this case report, we describe a patient with locally advanced PTC in whom treatment with sorafenib provided sufficient tumor reduction to allow thyroidectomy and RAI therapy, suggesting a potential role of sorafenib as an induction therapy of unresectable DTC.

Long term outcome and side effects in patients receiving low-dose I125 brachytherapy: a retrospective analysis

ABSTRACT Objectives: To retrospectively evaluate the disease free survival (DFS), disease specific survival (DSS),overall survival (OS) and side effects in patients who received low-dose rate (LDR) brachytherapy with I125 stranded seeds. Materials and methods: Between july 2003 and august 2012, 274 patients with organ confined prostate cancer were treated with permanent I125 brachytherapy. The median follow-up, age and pretreatment prostate specific antigen (iPSA) was 84 months (12-120), 67 years (50-83) and 7.8 ng/mL (1.14-38), respectively. Median Gleason score was 6 (3-9). 219 patients (80%) had stage cT1c, 42 patients (15.3%) had stage cT2a, 3 (1.1%) had stage cT2b and 3 (1.1%) had stage cT2c. The median D90 was 154.3 Gy (102.7-190.2). Results: DSS was 98.5%.OS was 93.5%. 13 patients (4.7%) developed systemic disease, 7 patients (2.55%) had local progression. In 139 low risk patients, the 5 year biochemical freedom from failure rate (BFFF) was 85% and 9 patients (6.4%) developed clinical progression. In the intermediate risk group, the 5 year BFFF rate was 70% and 5 patients (7.1%) developed clinical progression. Median nPSA in patients with biochemical relapse was 1.58 ng/mL (0.21 – 10.46), median nPSA in patients in remission was 0.51 ng/mL (0.01 – 8.5). Patients attaining a low PSA nadir had a significant higher BFFF (p<0.05). Median D90 in patients with biochemical relapse was 87.2 Gy (51 – 143,1). Patients receiving a high D90 had a significant higher BFFF (p<0.05). Conclusion: In a well selected patient population, LDR brachytherapy offers excellent outcomes. Reaching a low PSA nadir and attaining high D90 values are significant predictors for a higher DFS.

Incidencia de patología salival sintomática aleada en pacientes tratados con yodo radioactivo por cáncer diferenciado de tiroides / Incidence of sympthomatic salivary disease in patients with differentiated thyroid cancer treated with radioactive iodine

Background: The radioactive iodine therapy for differentiated thyroid cancer can produce severe and frequent salivary symptoms, during the treatment or later. Aim: To analyze the incidence, severity and charactheristics of the salivary signs and symptoms in these patients. Patients and Method: Retrospective and descriptive analisis of 106 patients with confirmed diagnosis of differentiated thyroid cancer, treated with surgery and radioactive iodine, that completed a telephonic survey for the evaluation of salivary symptoms. Results: 26 (24.52 percent) patients presented with salivary symptoms or signs after the radioactive iodine therapy (mean 5 months). The average doses of I 131 was 128,5 mCi. Xerostomy, pain, xeroftalmy, inflammation, sialoadenitis and dysgeusia, were the most frequent clinical symptoms. Conclusions: After radioactive iodine therapy the salivary symptoms and signs incidence is high. We conclude that the indication for this treatment must be selective, but in accordance with the oncological risk of each patient.

Introducción: El tratamiento con yodo radioactivo en el tratamiento del cáncer diferenciado de tiroides puede originar síntomas alejados de origen salival. Éstos pueden llegar a ser intensos y frecuentes. Objetivo: Conocer la incidencia, características e intensidad de dichos síntomas. Material y Método: Revisión retrospectiva y análisis descriptivo de 106 pacientes con diagnóstico definitivo y anatomopatológico de cáncer diferenciado de tiroides, tratados con yodo radioactivo, que contestaron una encuesta telefónica especialmente diseñada para evaluación de patología salival. Resultados: Veintiséis (24,52 por ciento) pacientes presentaron y consultaron por síntomas y/o signos alejados (promedio 5 meses) de la terapia ablativa, de origen salival. La dosis promedio fue de 128,5 mCi de I 131. Los síntomas más frecuentes fueron xerostomía, dolor, xeroftalmia, inflamación, sialoadenitis y alteración del gusto. Discusión: La incidencia de signos y síntomas salivales alejados en pacientes tratados con I 131 es alta y justificaría a nuestro juicio su indicación selectiva, de acuerdo a los riesgos de recurrencia tumoral de cada paciente.

Is thyroid stunning clinically relevant? A retrospective analysis of 208 patients / O atordoamento da tireoide é clinicamente relevante? Análise retrospectiva de 208 pacientes

Objective : Current guidelines have advised against the performance of 131I-iodide diagnostic whole body scintigraphy (dxWBS) to minimize the occurrence of stunning, and to guarantee the efficiency of radioiodine therapy (RIT). The aim of the study was to evaluate the impact of stunning on the efficacy of RIT and disease outcome.Subjects and methods : This retrospective analysis included 208 patients with differentiated thyroid cancer managed according to a same protocol and followed up for 12-159 months (mean 30 ± 69 months). Patients received RIT in doses ranging from 3,700 to 11,100 MBq (100 mCi to 300 mCi). Post-RIT-whole body scintigraphy images were performed 10 days after RIT in all patients. In addition, images were also performed 24-48 hours after therapy in 22 patients. Outcome was classified as no evidence of disease (NED), stable disease (SD) and progressive disease (PD).Results : Thyroid stunning occurred in 40 patients (19.2%), including 26 patients with NED and 14 patients with SD. A multivariate analysis showed no association between disease outcome and the occurrence of stunning (p = 0.3476).Conclusion : The efficacy of RIT and disease outcome do not seem to be related to thyroid stunning. Arq Bras Endocrinol Metab. 2014;58(3):292-300.

Objetivo : As diretrizes atuais alertam contra a execução da cintigrafia de corpo inteiro com iodo-131 (dxWBS) para minimizar a ocorrência de atordoamento e garantir a eficiência do tratamento com radioiodo (RIT). O objetivo deste estudo foi avaliar o impacto do atordoamento sobre a eficácia do RIT e desfechos da doença.Sujeitos e métodos : Esta análise retrospectiva incluiu 208 pacientes com câncer diferenciado de tireoide submetidos ao mesmo protocolo e acompanhados por 12-159 semanas (média de 30 ± 69 meses). Os pacientes receberam RIT com doses variando de 3.700 a 11.100 MBq (100 mCi a 300 mCi). As imagens da cintigrafia após a RIT foram feitas 10 dias depois da RIT em todos os pacientes. Além disso, as imagens foram também obtidas após 24-48h em 22 pacientes. O desfecho foi classificado como nenhuma evidência de doença (NED), doença estável (SD) e doença progressiva (PD).Resultados : O atordoamento da tireoide ocorreu em 40 pacientes (19,2%), incluindo 26 pacientes com NED e 14 pacientes com SD. A análise multivariada não mostrou associação entre o desfecho da doença e a ocorrência de atordoamento (p = 0,3476).Conclusão : A eficácia da RIT e o desfecho da doença não parecem estar relacionados com o atordoamento da tireoide. Arq Bras Endocrinol Metab. 2014;58(3):292-300.

Iodoterapia de baixas doses (30mCi e 50mCi) em regime ambulatorial, para casos de carcinoma diferenciado da tireoide, classificados como de baixo risco ou de risco intermediário / Low dose iodine therapy (30mCi and 50mCi) in the outpatient setting, for cases of differentiated thyroid carcinoma classified as low risk or intermediate risk

A radioiodoterapia tem duas finalidades: -radioablação: utilizada após a tireoidectomia total, com o objetivo de destruir tecido tireoidiano remanescente, em geral tecido normal, e facilitar o acompanhamento com a dosagem de tireoglobulina sérica. Em geral são utilizadas atividades de 1.100 a 3.700 MBq (30 a 100 mCi); e -terapêutica: além de buscar destruir tecido remanescente, elimina micrometástases locoregionais e metástases à distância. Em geral são utilizadas atividades acima de 3.700 MBq (100 mCi). O objetivo principal da Radioiodoterapia (RIT) é a redução do risco de desfechos desfavoráveis relacionados ao tumor e não apenas facilitar o seguimento. Esta recomendação se justifica também no objetivo de se evitar complicações precoces e tardias relacionadas à exposição ao radioiodo. A atividade a ser administrada de radioiodo em pacientes com Carcinoma Diferenciado da Tireoide (CDT) varia de acordo com o objetivo do tratamento. É importante salientar que a terapia deve ser a mais eficaz possível com o menor risco de exposição à radiação necessária. Nos pacientes de baixo risco que sejam considerados como tendo benefício clínico com a RIT, o objetivo do tratamento é promover a ablação de tecido remanescente. Esta ablação pode ser definida como a ausência de captação de radioiodo em leito tireoidiano em estudo cintilográfico, ou a ausência de níveis séricos detectáveis de tireoglobulina estimulada. As doses baixas são de administração ambulatorial e que essa inclusão não trará impacto financeiro para o SUS, vez que, hoje, os doentes de baixo risco ou de risco intermediário e sem suspeita de doença residual microscópica, indicações para doses baixas, são tratados com doses de 100 mCi, que exigem internação em quartos especificamente destinados para esse tratamento e limitam o acesso a ele. Os membros da CONITEC presentes na 18ª reunião do plenário realizada nos dias 31/7 e 1/8/2013 recomendaram a ampliação de uso da iodoterapia de baixas doses (30mci e 50mci), em regime ambulatorial, para casos de carcinoma diferenciado da tireoide classificados como de baixo risco ou de risco intermediário.

Episcleral plaque brachytherapy using ‘BARC I-125 Ocu-Prosta seeds’ in the treatment of intraocular tumors: A single-institution experience in India.

Context: To analyze the results of episcleral plaque brachytherapy using indigenous Bhabha Atomic Research Centre (BARC) Iodine-125 Ocu-Prosta seeds for the management of intraocular tumors from a single institute. AIM: To report our initial experience and learning curve on the use of ‘BARC I-125 Ocu-Prosta seeds’ for the management of intraocular tumors such as choroidal melanomas, retinoblastomas and vasoproliferative tumors (VPT). Materials and Methods: We retrospectively reviewed 13 eyes of 13 patients who underwent ophthalmic brachytherapy between May 2008 to March 2012. Nine cases had choroidal melanomas; three had retinoblastomas while one case had VPT. Results: For choroidal melanomas the average apical diameter before brachytherapy was 7.6 mm and average largest basal diameter was 12.1 mm, respectively, which reduced to 4.2 mm and 7.7 mm after the procedure at an average follow-up of 24 months (range 10-43 months). Retinoblastoma and VPT also showed good regression after brachytherapy. Conclusion: Plaque radiotherapy using 125I seeds can be performed under peribulbar anesthesia and provides a viable option for the management of intraocular cancer with minimal invasiveness and surgical complications. Patients in our studies experienced excellent local tumor control. With the availability of indigenous ‘BARC I-125 Ocu-Prosta seeds’ locally, cost effective ophthalmic brachytherapy can be performed in India.

Correlação entre volume tireoidiano determinado pelo método de ultrassonografia versus cintilografia e sua implicação em cálculos dosimétricos na terapia com radioiodo na doença de Graves / Correlation between thyroid volume determined either by ultrasound or by scintigraphy and its implications in dosimetric radioiodine calculations in Graves disease treatment

INTRODUÇÃO: A doença de Graves (DG) é a causa mais comum de hipertireoidismo e, entre as abordagens terapêuticas mais utilizadas para o tratamento do hipertireoidismo por doença de Graves, encontram-se a cirurgia, o uso de drogas antitireoidianas e a radioiodoterapia. No cálculo dosimétrico para determinação da dose de radioiodo a ser utilizada, é possível empregar a ultrassonografia e a cintilografia para avaliar o volume tireoidiano. OBJETIVO: O presente estudo visa correlacionar essas metodologias com ênfase no volume obtido e nas implicações dosimétricas. SUJEITOS E MÉTODOS: Foram incluídos no estudo 103 pacientes com diagnóstico de DG encaminhados para radioiodoterapia. Esses foram submetidos à ultrassonografia da tireoide e à cintilografia tireoidiana, com cálculo de volume pela cintilografia baseado na fórmula de Allen. RESULTADOS E CONCLUSÕES: Observou-se boa correlação entre os dois métodos, porém com massa estimada pela cintilografia sistematicamente maior que a estimada pela ultrassonografia, o que pode acarretar em menor estimativa de dose absorvida quando utilizado o método cintilográfico.

INTRODUCTION: Graves disease (GD) is the most common cause of hiperthyroidism, and the most common treatment options are surgery, antithyroid drugs and radioiodine therapy. In radiodosimetric calculations to determine radioiodine dosage it is possible to use thyroid volume estimatives based on ultrasound or scintigraphy. OBJECTIVE: The present study aimed to correlate these methodologies emphasizing volume estimatives and dosimetric implications. SUBJECTS AND METHODS: Were included 103 patients with GD diagnosis and indication of radioiodine treatment. They were submitted to thyroid ultrasound and thyroid scintigraphy. RESULTS AND CONCLUSIONS: Good correlation between both methods was observed, although scintigraphy systematically obtained greater volumes than ultrasound implying in lower estimatives of absorbed dose when scintigraphy is used.

Transient cytotoxicity of 131I beta radiation in hyperthyroid patients treated with radioactive iodine.

Background & objectives: Radioiodine (131I) or radioactive iodine in low doses is used worldwide as the first line of management in the treatment of hyperthyroidism. Information is available on the extent and severity of cell damage after a high dose radioiodine (131I) therapy for thyroid cancer, but information is scanty on its cellular effects, its extent and severity of cell damage after a low dose 131I therapy. The present investigation was aimed to study the cytotoxic effects of a low dose 131I therapy in varying doses as is normally being used in routine clinical practice in the treatment of various forms of hyperthyroidism. Methods: Peripheral blood lymphocytes were analyzed in 32 hyperthyroid patients. All of them received 131I in the form of sodium iodide solution orally. Blood lymphocytes were studied for the presence of chromosomal aberrations (CA) and micro nucleus (MN) using micronucleus assay. Blood samples of these patients were drawn prior to the treatment, on 7 thand 30 thdays after the treatment. Results: The results indicated a positive relationship between 131I dose, CA and MN frequency. A statistically significant increase in CA and MN frequency in day 7 post- therapy and a decrease in mean levels of CA and MN on day 30 post-therapy were observed when compared to pre-therapy. Interpretation & conclusions: This study showed that the cytogenetic damage induced by 131I in low doses i.e., less than 555MBq was minimal and reversible. Patients can be motivated to undertake this safe and easy procedure as a first line of therapy in the treatment of hyperthyroidism.

Radioiodine therapy for hyperthyroidism

Radioiodine therapy is the safest, simplest, least expensive and most effective method for treatment of hyperthyroidism. The method employed in this research was a systematic bibliographic review, in which only valid studies or the clinically detailed enough open-labeled studies using validated scales were used. Iodine-131 [I-131] acts by the destructive effect of short-range beta radiation on thyroid cells. Indications for radioiodine therapy include toxic nodules [in which I-131 is the first choice of treatment], recurrent hyperthyroidism after antithyroid treatment or surgery, intolerance to antithyroid therapy due to side-effects and patient preference. Due to difficulties in previous methods for dose determination, fixed dose method of I-131 is now considered the best practical method for radioiodine therapy in primary hyperthyroidism. Absolute contraindications for radioiodine treatment are pregnancy and lactation. In pediatric patients, radioiodine therapy can be used, but is mainly considered in recurrent toxic goiter and when antithyroid medication is ineffective. There is no clear evidence indicative of carcinogenic or teratogenic effect of this agent

Cumulative doses of radioiodine in the treatment of differentiated thyroid carcinoma: knowing when to stop / Doses cumulativas de iodo radioativo no tratamento do carcinoma diferenciado de tireoide: sabendo a hora de parar

OBJECTIVE: Evaluate the efficacy of cumulative doses (CDs) of 131I-iodide therapy (RIT) in differentiated thyroid cancer (DTC). SUBJECTS AND METHODS: The probability of progressive disease according to CDs was evaluated in patients < 45 years old and > 45 years old and correlated to tumor-node-metastasis (TNM), thyroglobulin values, histological types and variants, age, and zduration of the disease. RESULTS: At the end of a follow-up period of 69 ± 56 months, 85 out of 150 DTC patients submitted to fixed doses RIT had no evidence of disease, 47 had stable disease and 18 had progressive disease. Higher CDs were used in the more aggressive variants (p < 0.0001), higher TNM stages (p < 0.0001), and follicular carcinomas (p = 0.0034). Probability of disease progression was higher with CDs > 600 mCi in patients > 45 years old and with CDs > 800 mCi in patients < 45 years. CONCLUSION: Although some patients may still respond to high CDs, the impact of further RIT should be carefully evaluated and other treatment strategies may be warranted.

OBJETIVO: Avaliar a eficácia de doses cumulativas (DCs) da terapia com iodeto-131I (RIT) no câncer diferenciado de tiroide (CDT). SUJEITOS E MÉTODOS: A probabilidade de doença em progressão conforme a DC foi calculada em pacientes com idade < 45 e > 45 anos e correlacionada com o TNM, valores de tiroglobulina sérica, tipos histológicos e variantes, idade e tempo de doença. RESULTADOS: Ao final de um seguimento de 69 ± 56 meses, 85 dos 150 pacientes CDT submetidos a doses fixas de RIT não tinham evidência de doença, 47 tinham doença estável e 18, doença progressiva. DCs mais elevadas foram usadas nas variantes agressivas (p < 0,0001), maior estágio TNM (p < 0,0001) e nos carcinomas foliculares (p = 0,0034). A probabilidade de doença em progressão foi maior com DCs > 600 mCi em pacientes > 45 anos e com DCs > 800 mCi em pacientes < 45 anos. CONCLUSÃO: Apesar de alguns pacientes ainda responderem a altas DCs, o impacto de RITs deve ser cuidadosamente avaliado e outras estratégias terapêuticas devem ser consideradas.

Is it necessary to reduce the radioiodine dose in patients with thyroid cancer and renal failure? / É necessário reduzir as atividades de radioiodo nas terapias de pacientes com câncer de tireoide e disfunção renal?

The objective of this study were to obtain dosimetric data from a patient with thyroid cancer simultaneously undergoing peritoneal dialysis therapy, so as to determine the appropriate amount of 131I activity to be applied therapeutically. Percentages of radioiodine in the blood and the whole-body were evaluated, and radiation absorbed doses were calculated according to OLINDA/EXM software. Whole-body 131I effective half-time was 45.5 hours, being four times longer than for patients without any renal dysfunction. Bone-marrow absorbed dose was 0.074 mGy/MBq, with ablative procedure maintenance at 3.7 GBq, as the reported absorbed dose was insufficiently restrictive to change the usual amount of radioiodine activity administered for ablation. It was concluded that radioiodine therapeutic-dose adjustment, based on individual patient dosimetry, is an important way of controlling therapy. It also permits the safe and potential delivery of higher doses of radiation to tumors and undesirable tissues, with a minimum of malignant effects on healthy tissues.

O objetivo do presente estudo foi determinar a atividade de radioiodo a ser administrada na terapia de um paciente portador de câncer de tireoide e simultaneamente tratado com diálise peritoneal. Percentuais de radioiodo em sangue e corpo-total foram avaliados após a administração de uma atividade traçadora e a dosimetria foi calculada utilizando o software OLINDA/EXM. A meia-vida efetiva do radioiodo em corpo-total foi de 45,5 horas, sendo quatro vezes maior que aquela observada em pacientes sem disfunção renal. A dose em medula óssea foi de 0,074 mGy/MBq, administrando-se uma atividade terapêutica de 3,7 GBq, uma vez que a estimativa de dose não foi suficientemente restritiva para mudar a atividade usual de radioiodo com função ablativa. Concluiu-se que a terapia individualizada de pacientes permite manter o equilíbrio entre o máximo de dose de radiação liberada em tumores ou tecidos indesejados com o mínimo de efeitos maléficos sobre tecidos sadios

Radioiodine plus recombinant human thyrotropin do not cause acute airway compression and are effective in reducing multinodular goiter

Recombinant human thyrotropin (rhTSH) reduces the activity of radioiodine required to treat multinodular goiter (MNG), but acute airway compression can be a life-threatening complication. In this prospective, randomized, double-blind, placebo-controlled study, we assessed the efficacy and safety (including airway compression) of different doses of rhTSH associated with a fixed activity of 131I for treating MNG. Euthyroid patients with MNG (69.3 ± 62.0 mL, 20 females, 2 males, 64 ± 7 years) received 0.1 mg (group I, N = 8) or 0.01 mg (group II, N = 6) rhTSH or placebo (group III, N = 8), 24 h before 1.11 GBq 131I. Radioactive iodine uptake was determined at baseline and 24 h after rhTSH and thyroid volume (TV, baseline and 6 and 12 months after treatment) and tracheal cross-sectional area (TCA, baseline and 2, 7, 180, and 360 days after rhTSH) were determined by magnetic resonance; antithyroid antibodies and thyroid hormones were determined at frequent intervals. After 6 months, TV decreased significantly in groups I (28.5 ± 17.6 percent) and II (21.6 ± 17.8 percent), but not in group III (2.7 ± 15.3 percent). After 12 months, TV decreased significantly in groups I (36.7 ± 18.1 percent) and II (37.4 ± 27.1 percent), but not in group III (19.0 ± 24.3 percent). No significant changes in TCA were observed. T3 and free T4 increased transiently during the first month. After 12 months, 7 patients were hypothyroid (N = 3 in group I and N = 2 in groups II and III). rhTSH plus a 1.11-GBq fixed 131I activity did not cause acute or chronic changes in TCA. After 6 and 12 months, TV reduction was more pronounced among patients treated with rhTSH plus 131I.

Radioiodoterapia do carcinoma diferenciado da tireoide: impacto radiológico da liberação hospitalar de pacientes com atividades entre 100 e 150 mCi de iodo-131 / Radioiodine therapy of differentiated thyroid cancer: radiologic impact of out-patient treatment with 100 to 150 mCi Iodine-131 activities

OBJETIVO: Determinar exposições decorrentes da radioiodoterapia ambulatorial do carcinoma diferenciado da tireoide (CDT) sobre os familiares dos pacientes e o meio ambiente. MÉTODOS: Administraram-se 100 a 150 mCi de (131I)NaI para tratamento ambulatorial de 20 pacientes com CDT. Monitorizaram-se com dosímetros termoluminescentes as doses de radiação recebidas por familiares (n = 27) e potenciais de dose nas residências. Também foram monitorizadas contaminação de superfície e rejeitos radioativos. RESULTADOS: Registraram-se doses < 1,0 mSv em 26 acompanhantes e 2,8 mSv em um caso, inferiores ao aceitável para exposições médicas (5,0 mSv/procedimento). Excetuando-se o quarto dos pacientes (média = 0,69 mSv), determinou-se potencial de dose nas residências < 0,25 mSv. A contaminação de superfícies (4,2 Bq.cm-2) não ultrapassou níveis de liberação, sem representar riscos mesmo em simulações do pior cenário. Os rejeitos radioativos tiveram volume de 2,5 litros e atividade estimada em 90 µCi (média = 4,5 µCi/paciente). CONCLUSÕES: Não foi constatado impacto radiológico ao meio ambiente ou aos familiares de pacientes tratados ambulatorialmente com 100 a 150 mCi de iodo-131 e acompanhados por profissionais qualificados.

PURPOSE:To evaluate exposure and dosimetry to family members and environment due to outpatient radioiodine therapy of differentiated thyroid carcinoma. METHODS: Twenty patients were treated with 100-150mCi of iodine-131 on an out-patient basis. Family members dosimetry (n = 27) and potential doses inside the house were measured with thermoluminescent dosimeters. Surface contamination and radioactive wastes were also monitored. RESULTS: Less than 1.0 mSv doses were found in 26 co-habitants and 2.8 mSv in a single case (inferior to the acceptable value of 5.0 mSv/procedure). Potential doses in the houses were inferior to 0.25 mSv, excluding the patients bedroom (mean value = 0.69 mSv). Surface contamination (mean = 4.2 Bq.cm-2) were below clearance levels. Radioactive wastes generated had a volume of 2.5 liters and a total activity estimated in 90 µCi, with a calculated exposure close to the background radiation levels. CONCLUSIONS: No radiological impact was detected after iodine therapy with 100-150 mCi on an out-patient basis followed by experienced professionals.

Protocol for thyroid remnant ablation after recombinant TSH in thyroid carcinoma / Protocolo para ablación de remanentes tiroideos luego de TSH recombinante en el cáncer diferenciado de tiroides

In some countries, in order to perform rhTSH-aided thyroid remnant ablation (TRA) after surgery, it is generally necessary to confirm that thyroidectomy has been almost complete. Otherwise, the nuclear medicine specialist will not administer a high radioiodine dose because it might be hazardous due to the possibility of thyroid remnant actinic thyroiditis. Considering this, it would be necessary to use two rhTSH kits (one for diagnostic purposes and the other one to administer the 131I dose). In this study, we used an alternative protocol for TRA with the use of one kit of rhTSH in twenty patients diagnosed with low risk papillary thyroid carcinoma. All patients had negative titers of anti-thyroglobulin antibodies. Successful thyroid remnant ablation was confirmed with an undetectable rhTSH stimulated thyroglobulin level (< 1 ng/ml) in all 20 patients between 8 to 12 months after radioiodine administration. The use of this protocol combining scintigraphy with the subsequent administration of a therapeutic dose following the administration of one kit of rhTSH would avoid the need of using 2 kits to perform the ablation and would decrease the costs associated with its use while significantly enhancing the quality of life of patients with thyroid cancer.

En algunos países, para realizar la ablación de los remanentes tiroideos con radioyodo después de la cirugía, generalmente se requiere confirmar que la tiroidectomía fue casi completa, ya que de otra manera el especialista en medicina nuclear no administrará una dosis elevada de radioyodo, considerando que esto puede ser dañino para el paciente debido a la posibilidad de generar una tiroiditis actínica. De acuerdo con esto, sería necesario administrar 2 kits de rhTSH (uno para diagnóstico y otro para la dosis de radioyodo). En este estudio, empleamos un protocolo alternativo para la ablación luego de la administración de un único kit (2 ampollas) de rhTSH en 20 pacientes con antecedentes de un carcinoma papilar de bajo riesgo. Todos los pacientes presentaban títulos negativos de anticuerpos anti-tiroglobulina. La ablación exitosa de remanente tiroideo se confirmó con un nivel no detectable de tiroglobulina (<1 ng/ml) al estímulo por rhTSH en los 20 pacientes, entre 8 a 12 meses luego de la ablación. El uso de este protocolo que combina la posibilidad de realizar un centellograma diagnóstico y la ablación luego del uso de un solo kit de rhTSH, facilita su empleo, disminuye los costos asociados, a la vez que permite una mejor calidad de vida de los pacientes con cáncer de tiroides.