74 MBq radioiodine 131I does not prevent uptake of therapeutic doses of 131I (i.e. it does not cause stunning) in differentiated thyroid cancer

Ir, McDougall

doi:10.1097/00006231-199706000-00002

Cited by 100 publications

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“…Thyroi d stunning is a complication of radiation therapy with 131 I, the consequences of which affect mainly the management of thyroid carcinoma patients (1)(2)(3)(4)(5)(6). The stunning phenomenon is characterized by less 131 I uptake at therapy than was predicted from the 131 I uptake measurement during dose planning.…”

mentioning

confidence: 99%

Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Lundh

Lindencrona²,

Postgård³

et al. 2009

J Nucl Med

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Recent clinical and experimental data demonstrate that thyroid stunning is caused by previous irradiation and may influence the efficacy of 131 I radiation therapy of thyroid cancer and possibly hyperthyroidism. To avoid stunning, many clinics have exchanged 131 I for 123 I for pretherapeutic diagnostic imaging and dose planning. Furthermore, recent in vitro studies indicate that 131 I irradiation reduces iodide uptake by downregulating the expression of the sodium iodide symporter (NIS). The rationale for this study was therefore to study effects on iodide transport and NIS messenger RNA (mRNA) expression in thyrocytes exposed to both 123 I and 131 I in addition to some other potentially interesting radionuclides. Methods: Thyrotropin-stimulated thyroid cell monolayers were exposed to 0.5 Gy of 123 I, 131 I, 99m Tc, or 211 At, all being radionuclides transported via NIS, in the culture medium for 6 h, or to various absorbed doses of 123 I or 131 I for 48 h. NIS mRNA expression was analyzed using quantitative reverse-transcriptase polymerase chain reaction. Results: Iodide transport and NIS mRNA expression were reduced by all radionuclides. At the same absorbed dose, iodide transport was reduced the most by 211 At, followed by 123 I and 99m Tc (equally potent), whereas 131 I was least effective. The onset of NIS downregulation was rapid (,1 d after irradiation) in cells exposed to 123 I or 211 At and was delayed in cells irradiated with 131 I or 99m Tc. Iodide transport and NIS expression were recovered only for 211 At. 123 I reduced the iodine transport and the NIS mRNA expression more efficiently than did 131 I at an equivalent absorbed dose, with a relative biological effectiveness of about 5. Conclusion: The stunning effect per unit absorbed dose is more severe for 123 I than for 131 I. Despite the lower absorbed dose per unit activity for 123 I than for 131 I, stunning by 123 I cannot be excluded in patients. The degree to which iodide transport capacity and NIS mRNA expression are reduced seems to be related to the biological effectiveness of the type of radiation delivering the absorbed dose to the target, with 211 At (which has the highest relative biological effectiveness) causing the highest degree of stunning per unit absorbed dose in the present study.

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Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Lundh

Lindencrona²,

Postgård³

et al. 2009

J Nucl Med

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“…Park et al (13) showed reduced activity on post-treatment (100-200mCi iodine-131) scans compared to DxSCANS in 40% of patients treated with 3mCi, 67% treated with 5mCi and 89% treated with 10mCi. Muratet et al (11) showed differences in the ablation of thyroid remnants (ablative dose of 100 mCi) when using a tracer dose of 1 and 3mCi (76 and 50% of success, respectively), and McDougall et al (10) did not detect stunning with a dose of 2mCi (only 1.4% of patients showed reduced therapeutic uptake).…”

Section: Discussionmentioning

confidence: 99%

“…Although stunning can be suspected to be responsible for the difference between pre-and posttreatment uptake (9,10,(13)(14)(15)(16), treatment efficacy seems to be the fundamental parameter in the definition of the impact of this phenomenon which, however, has not been considered in all studies. Morris et al (8) did not observe differences in the success of ablative therapy between patients submitted or not to pretreatment scanning with 5mCi iodine-131 (64.9 and 66.7%, respectively).…”

Section: Rosário Et Almentioning

confidence: 99%

“…This phenomenon, called stunning effect, does not seem to occur when treatment is performed less than 5 days after diagnostic scanning (8)(9)(10), or when the diagnostic iodine-131 dose administered does not exceed 2mCi (10,11), a less sensitive dose (12).…”

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confidence: 99%

“…The lack or decrease of iodine uptake on posttreatment scans suggests the occurrence of the stunning effect (9,10,(13)(14)(15)(16), but other parameters should also be taken into account, mainly the efficacy of ablation which is the main end-point (8,9,11,14,(16)(17)(18).…”

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confidence: 99%

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5mCi pretreatment scanning does not cause stunning when the ablative dose is administered within 72 hours

Rosário

Barroso

Rezende

et al. 2005

Arq Bras Endocrinol Metab

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Objective: To determine the stunning effect of a tracer dose of 5mCi iodine-131. Patients and Methods: We retrospectively analyzed 145 patients who received the first ablative treatment at our service. Patients were divided according to disease status determined upon post-treatment scanning (101 patients with thyroid remnants and 44 with pulmonary metastases) and whole-body scanning before ablation (performed on 69 individuals). All patients with thyroid remnants were treated with an ablative dose of 100mCi and those with metastases received 200mCi. Results: In patients with remnants only (n= 41) or metastases (n= 28) submitted to diagnostic scanning, uptake was found to be apparently increased in most patientscases (71 and 73%, respectively) 7 days after therapy, while reduced uptake (visual) was not observed in any patient. The efficacy of ablation was similar in the groups submitted or not to diagnostic scanning: 71 and 80% in patients without metastases (p= 0.28), respectively, and 43 and 50% in those with pulmonary involvement (p= 0.64). Conclusion: The present results indicate that diagnostic scanning using a 5mCi iodine-131 dose does not interfere with uptake of the ablative dose or with treatment efficacy when ablation is performed within 72h. Objetivo: Determinar a interferência de uma dose traçadora de 5mCi de 131 I. Pacientes e Método: Nós analisamos retrospectivamente 145 pacientes que receberam o primeiro tratamento ablativo em nosso serviço. Eles foram divididos de acordo com o estadio da doença determinado pelo rastreamento pós-terapêutico (101 pacientes com remanescentes tireoidianos e 44 com metástases pulmonares) e scanning de corpo inteiro antes da ablação (realizada em 69 indivíduos). Todos os pacientes com remanescentes tireoidianos foram tratados com uma dose ablativa de 100mCi e aqueles com metástases receberam 200mCi. Resultados: Nos pacientes com remanescentes apenas (n= 41) ou metastases (n= 28) submetidos ao scanning diagnóstico, a captação encontrava-se aparentemente aumentada na maioria dos patientscasos (71 e 73%, respectivamente) 7 dias após a terapia, enquanto captação reduzida (visual) não foi observada em nenhum paciente. A eficácia da ablação foi similar nos grupos submetidos ou não ao rastreamento diagnóstico: 71 e 80% em pacientes sem metástases (p= 0,28), respectivamente, e 43 e 50% naqueles com envolvimento pulmonar (p= 0,64). Conclusão: Esses resultados indicam que o rastreamento diagnóstico usando uma dose de 5mCi de 131 I não interefere com a captação da dose ablativa ou com a eficácia do tratamento quando a ablação é realizada dentro de 72h.

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Contemporary considerations in adjuvant radioiodine treatment of adults with differentiated thyroid cancer

Juweid

Tülchinsky

Mismar

et al. 2020

Intl Journal of Cancer

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Differentiated thyroid cancer (DTC) is the most common endocrine malignancy with a growing incidence worldwide. The initial conventional management is surgery, followed by consideration of 131I treatment that includes three options. These are termed remnant ablation (targeting benign thyroid remnant), adjuvant (targeting presumed microscopic DTC) and known disease (targeting macroscopic DTC) treatments. Some experts mostly rely on clinicopathologic assessment for recurrence risk to select patients for the 131I treatment. Others, in addition, apply radioiodine imaging to guide their treatment planning, termed theranostics (aka theragnostics or radiotheragnostics). In patients with low‐risk DTC, remnant ablation rather than adjuvant treatment is generally recommended and, in this setting, the ATA recommends a low 131I activity. 131I adjuvant treatment is universally recommended in patients with high‐risk DTC (a primary tumor of any size with gross extrathyroidal extension) and is generally recommended in intermediate‐risk DTC (primary tumor >4 cm in diameter, locoregional metastases, microscopic extrathyroidal extension, aggressive histology or vascular invasion). The optimal amount of 131I activity for adjuvant treatment is controversial, but experts reached a consensus that the 131I activity should be greater than that for remnant ablation. The main obstacles to establishing timely evidence through randomized clinical trials for 131I therapy include years‐to‐decades delay in recurrence and low disease‐specific mortality. This mini‐review is intended to update oncologists on the most recent clinical, pathologic, laboratory and imaging variables, as well as on the current 131I therapy‐related definitions and management paradigms, which should optimally equip them for individualized patient guidance and treatment.

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74 MBq radioiodine 131I does not prevent uptake of therapeutic doses of 131I (i.e. it does not cause stunning) in differentiated thyroid cancer

Cited by 100 publications

References 0 publications

Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

5mCi pretreatment scanning does not cause stunning when the ablative dose is administered within 72 hours

Contemporary considerations in adjuvant radioiodine treatment of adults with differentiated thyroid cancer

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74 MBq radioiodine 131I does not prevent uptake of therapeutic doses of 131I (i.e. it does not cause stunning) in differentiated thyroid cancer

Cited by 100 publications

References 0 publications

Radiation-Induced Thyroid Stunning: Differential Effects of 123I, 131I, 99mTc, and 211At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Radiation-Induced Thyroid Stunning: Differential Effects of 123I, 131I, 99mTc, and 211At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

5mCi pretreatment scanning does not cause stunning when the ablative dose is administered within 72 hours

Contemporary considerations in adjuvant radioiodine treatment of adults with differentiated thyroid cancer

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Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells

Radiation-Induced Thyroid Stunning: Differential Effects of ¹²³I, ¹³¹I, ^99mTc, and ²¹¹At on Iodide Transport and NIS mRNA Expression in Cultured Thyroid Cells