[Contribution of computed tomography in patients with lung metastases of differentiated thyroid carcinoma not apparent on plain radiography who were treated with radioiodine]. / Contribuição da tomografia computadorizada em pacientes com metástases pulmonares de carcinoma diferenciado de tireóide não-aparentes na radiografia e tratados com radioiodo.

Computed tomography (CT or CAT Scan) of the chest is more sensitive than radiography in the detection of lung metastases of differentiated thyroid cancer (DTC), but little information is available regarding the aggregated value of this method. The present study evaluated the response of patients with lung metastases of DTC not apparent on radiography to treatment with 131I and the value of CT in these cases. Twenty-five patients with lung metastases not apparent on radiography, who initially received 100-200 mCi I151, were evaluated and those presenting pulmonary uptake on post-therapy WBS were submitted to a new treatment after 6 to 12 months, and so on. The chance of detection of pulmonary uptake on post-therapy WBS did not differ between patients with negative and positive CT (100% versus 91.5%). Mean serum Tg levels were higher in patients with positive CT (108 ng/ml versus 52 ng/ml). Negative post-therapy WBS was achieved in 82% of patients with positive CT and in 92.3% with negative CT and the cumulative I131 activity necessary to achieve this outcome did not differ between the two groups (mean=300 mCi). Stimulated Tg was undetectable in 47% of patients with negative CT at the end of treatment, but in none of the patients whose CT continued to be positive. In patients with elevated Tg, the CT result apparently did not change the indication of therapy or the I131 activity to be administered. In cases with lung metastases, the persistence of micronodules on CT was associated with the persistence of detectable Tg in patients presenting negative post-therapy WBS.

Contribuição da tomografia computadorizada em pacientes com metástases pulmonares de carcinoma diferenciado de tireóide não-aparentes na radiografia e tratados com radioiodo / Contribution of computed tomography in patients with lung metastases of differentiated thyroid carcinoma not apparent on plain radiography who were treated with radioiodine

A tomografia computadorizada (TC) de tórax é mais sensível que a radiografia na detecção de metástases pulmonares do carcinoma diferenciado de tireóide (CDT), sendo importante conhecer melhor o valor agregado desse método. Este estudo avaliou a resposta ao tratamento com 131I em pacientes com metástases pulmonares de CDTs não-aparentes na radiografia e o valor da TC nesses casos. Foram avaliados 25 pacientes com metástases pulmonares não-aparentes na radiografia, que receberam inicialmente 100 a 200 mCi de 131I. Naqueles com pesquisa de corpo inteiro (PCI) pós-dose com captação pulmonar, um novo tratamento era realizado após seis a 12 meses, e assim sucessivamente. A chance do encontro de captação pulmonar na PCI pós-dose não foi diferente em pacientes com TC negativa ou positiva (100 por cento versus 91,5 por cento). Os valores médios de tireoglobulina (Tg) sérica foram maiores naqueles com TC positiva (108 ng/mL versus 52 ng/mL). PCI pós-dose negativa foi alcançada em 82 por cento dos pacientes com TC positiva e em 92,3 por cento com TC negativa, e a atividade acumulada de 131I para alcançar essa resposta não foi diferente nos dois grupos (em média, 300 mCi). Quarenta e sete por cento dos pacientes com TC negativa ao final do tratamento apresentaram Tg estimulada indetectável, mas nenhum daqueles que permaneceu com TC positiva apresentou-a. Em pacientes com Tg elevada, o resultado da TC aparentemente não altera a indicação da terapia e a atividade de 131I a ser administrada. Nos casos com metástases pulmonares, a permanência de micronódulos na TC nos pacientes com PCI pós-dose negativa após o tratamento foi associada à persistência de Tg detectável.

Computed tomography (CT or CAT Scan) of the chest is more sensitive than radiography in the detection of lung metastases of differentiated thyroid cancer (DTC), but little information is available regarding the aggregated value of this method. The present study evaluated the response of patients with lung metastases of DTC not apparent on radiography to treatment with 131I and the value of CT in these cases. Twenty-five patients with lung metastases not apparent on radiography, who initially received 100-200 mCi I151, were evaluated and those presenting pulmonary uptake on post-therapy WBS were submitted to a new treatment after 6 to 12 months, and so on. The chance of detection of pulmonary uptake on post-therapy WBS did not differ between patients with negative and positive CT (100 percent versus 91.5 percent). Mean serum Tg levels were higher in patients with positive CT (108 ng/ml versus 52 ng/ml). Negative post-therapy WBS was achieved in 82 percent of patients with positive CT and in 92.3 percent with negative CT and the cumulative I131 activity necessary to achieve this outcome did not differ between the two groups (mean = 300 mCi). Stimulated Tg was undetectable in 47 percent of patients with negative CT at the end of treatment, but in none of the patients whose CT continued to be positive. In patients with elevated Tg, the CT result apparently did not change the indication of therapy or the I131 activity to be administered. In cases with lung metastases, the persistence of micronodules on CT was associated with the persistence of detectable Tg in patients presenting negative post-therapy WBS.

Is adjuvant therapy useful in patients with papillary carcinoma smaller than 2 cm?

To evaluate tumor recurrence after total thyroidectomy in patients with single papillary carcinoma with size 0.5 mIU/L in >or=50% of the measurements in all patients. Complete remission (stimulated thyroglobulin (Tg) 0.05). Six patients who still had stimulated Tg > 1 ng/mL (<5 ng/mL) showed a >50% decrease in comparison with Tg measured 12-24 months earlier. In conclusion, we suggest a more conservative approach with respect to central-compartment neck dissection, postoperative (131)I, and suppressive therapy in patients with small tumors restricted to the thyroid.

Management of low-risk patients with thyroid carcinoma and detectable thyroglobulin on T4 after thyroidectomy and ablation with iodine-131.

OBJECTIVE: To evaluate the positive predictive value of detectable Tg during T4 therapy (Tg on T4) in patients with thyroid cancer after total thyroidectomy and remnant ablation, discussing the work-up in this situation and the empirical indication of 131I. PATIENTS AND METHODS: Initially, 234 low-risk patients [tumor < 5cm, completely resected, no extensive extrathyroid invasion (pT4)] submitted to total thyroidectomy and ablation with 131I (3.7-5.5 GBq) who presented no ectopic uptake on RxWBS were studied. Of these, 23 patients with detectable Tg on T4 (> 1ng/ml) during the first year after initial therapy were selected. RESULTS: Metastases were detected by neck US in 7 patients, by chest CT in 2 and by US and CT in 3. Four of five patients with lung metastases upon CT had a positive RxWBS. Eleven patients with negative US and CT received a new 131I dose (without DxWBS), and RxWBS showed ectopic uptake in 3 patients. Among the patients with negative RxWBS, 7 remained free of apparent disease and Tg was declining (5 with undetectable Tg on T4 at the end of the study). One patient presented an increase in Tg and FDG-PET was positive for lymph node and bone metastases. CONCLUSIONS: All patients with Tg on T4 > 5ng/ml presented apparent disease. In these cases, even when US and CT are negative, the administration of a therapeutic dose of 131I (without DxWBS) and FDG-PET are recommended. Among patients with detectable Tg on T4

Management of low-risk patients with thyroid carcinoma and detectable thyroglobulin on T4 after thyroidectomy and ablation with iodine-131

OBJECTIVE: To evaluate the positive predictive value of detectable Tg during T4 therapy (Tg on T4) in patients with thyroid cancer after total thyroidectomy and remnant ablation, discussing the work-up in this situation and the empirical indication of 131I. PATIENTS AND METHODS: Initially, 234 low-risk patients [tumor < 5cm, completely resected, no extensive extrathyroid invasion (pT4)] submitted to total thyroidectomy and ablation with 131I (3.7­5.5 GBq) who presented no ectopic uptake on RxWBS were studied. Of these, 23 patients with detectable Tg on T4 (> 1ng/ml) during the first year after initial therapy were selected. RESULTS: Metastases were detected by neck US in 7 patients, by chest CT in 2 and by US and CT in 3. Four of five patients with lung metastases upon CT had a positive RxWBS. Eleven patients with negative US and CT received a new 131I dose (without DxWBS), and RxWBS showed ectopic uptake in 3 patients. Among the patients with negative RxWBS, 7 remained free of apparent disease and Tg was declining (5 with undetectable Tg on T4 at the end of the study). One patient presented an increase in Tg and FDG-PET was positive for lymph node and bone metastases. CONCLUSIONS: All patients with Tg on T4 > 5ng/ml presented apparent disease. In these cases, even when US and CT are negative, the administration of a therapeutic dose of 131I (without DxWBS) and FDG-PET are recommended. Among patients with detectable Tg on T4 < 5ng/ml and negative US and CT, only 12 percent presented ectopic uptake on RxWBS. These cases could be followed up by monitoring Tg on T4, and RxWBS and FDG-PET should only be performed if this marker does not decrease after 1­2 years.

OBJETIVO: Avaliar o valor preditivo positivo da Tg detectável durante terapia com T4 (Tg sob T4) em pacientes com câncer de tireóide após tireoidectomia total e ablação dos remanescentes, discutindo o manuseio dessa situação e a indicação empírica de 131I. PACIENTES E MÉTODOS: Inicialmente, foram estudados 234 pacientes de baixo risco [tumor < 5cm, completamente ressecado, sem invasão extratireoideana extensa (pT4)] submetidos à tireoidectomia total e ablação com 131I (3,7­5,5 GBq) que não apresentaram captação ectópica com RxWBS. Desses, foram selecionados 23 pacientes com Tg detectável com T4 (> 1ng/ml) durante o primeiro ano após a terapia inicial. RESULTADOS: Metástases foram detectadas em 7 pacientes pelo US cervical, em 2 pela TC de tórax e em 3 pela US e TC. Quatro de 5 pacientes com metástases pulmonares à TC tiveram um RxWBS positivo; 11 pacientes com US e TC negativos receberam uma nova dose de 131I (sem DxWBS), e a RxWBS mostrou captação ectópica em 3 pacientes. Entre os pacientes com RxWBS negativo, 7 permaneceram livres de doença aparente e a Tg estava em declínio (5 com Tg indetectável sob T4 ao final do estudo). Um paciente apresentou aumento da Tg e o FDG-PET foi positivo para linfonodos e metástases ósseas. CONCLUSÕES: Todos os patients com Tg sob T4 > 5ng/ml apresentaram doença aparente. Nesses casos, mesmo quando a US e a TC são negativos, é recomendada a administração de dose terapêutica de 131I (sem DxWBS) e FDG-PET. Em pacientes com Tg detectável sob T4 < 5ng/ml, mas US e TC negativos, apenas 12 por cento apresentaram captação ectópica com a RxWBS. Estes casos podem ser seguidos pelo monitoramento da Tg sob T4, e RxWBS e FDG-PET devem ser feitos apenas se esse marcador não diminuir.

Positive predictive value of detectable stimulated tg during the first year after therapy of thyroid cancer and the value of comparison with Tg-ablation and Tg measured after 24 months.

This study evaluated the positive predictive value (PPV) of detectable stimulated thyroglobulin during the first year after treatment of thyroid carcinoma (Tg-1) and the value of comparison with Tg-ablation and measured after 24 months (Tg-2). Forty-two consecutive patients undergoing total thyroidectomy and ablation with detectable Tg-1 (>1ng/mL) were selected. The patients had well-differentiated tumors, which were completely resected, and there was no ectopic uptake on whole body scan after 3.7-5.5GBq I(131). Imaging methods during follow-up revealed metastases in 10 patients (24%) (15% if Tg-1 10 ng=mL). Tg-ablation (cutoff of 10 ng/mL) presented a negative predictive value (NPV) of 91% and PPV of 42%. Comparing Tg-ablation with Tg-1, the PPV of an increase was 100%, whereas the NPV of a decrease was 88%. Thirty-six patients presented negative imaging results upon first assessment and Tg-1 was compared to Tg-2. Metastases were detected in all patients who presented an increase in Tg (n=4), whereas patients without variation (n=4) or with a decrease (n=28) showed no apparent disease. Among disease-free patients (n=32), 50% presented undetectable Tg and 40% showed a >50% decrease after 2 years. In conclusion, most patients with detectable stimulated Tg during the first year after therapy had no metastases, and evaluation of the slope of Tg helped discriminate cases with apparent disease.

Testicular function after radioiodine therapy in patients with thyroid cancer.

Our aim was to assess testicular function in patients treated with high-dose radioiodine. Luteinizing hormone (LH), follicle-stimulating hormone (FSH), and testosterone levels were determined in 52 men with thyroid carcinoma before and 6, 12, and 18 months after radioiodine therapy (3.7-5.5 GBq (131)I; mean, 4.25 GBq (131)I) (group 1) and were also determined before and 18 months after the last radioiodine therapy in 22 patients who received high cumulative activities (13-27.7 GBq; mean, 20.3 GBq (131)I) (group 2). FSH levels were increased 6 months after therapy in all patients of group 1, while a decline was observed after 12 months, with 37 of 52 (71%) subjects presenting normal values. FSH values returned to normal after 18 months in all patients. In group 2, 12 of 22 (54.5%) patients presented elevated FSH and 8 (66%) of these individuals had oligospermia. Six months after radioiodine, increased LH levels were observed in only 5 of 52 (9.6%) patients of group 1, which returned to normal after 12 months, and in 5 of 22 (22%) of group 2. All patients showed normal testosterone levels. We conclude that 131I therapy may cause impairment of testicular function. A generally transient increase in FSH is highly common but is usually reversed within 18 months. Oligospermia was common (one third) after high cumulative (131)I activities. Becausee we did not perform a spermiogram before therapy, we cannot state that high cumulative (131)I activities cause permanent infertility. We recommend the routine use of sperm banks in the cases of men who still wish to have children and who will undergo therapy with (131)I activities of 14 GBq or more or in the case of patients with pelvic metastases.

Managing thyroid cancer without thyroxine withdrawal.

Thyroxine (T4) withdrawal or recombinant TSH is used for the stimulation of thyroglobulin (Tg), whole-body scanning (WBS) and iodine-131 treatment in patients with thyroid carcinoma. This study evaluated the T4 dose reduction protocol as an alternative for patients' preparation. Fifty-one patients were submitted to total T4 withdrawal for WBS and Tg measurement. T4 treatment was then resumed and maintained until TSH reached levels < 0.3 mIU/l. The T4 dose was then decreased to 0.8 microg/kg/day and TSH was measured weekly. Tg was assayed when TSH was > 30 mIU/l. Patients diagnosed with the disease upon initial evaluation were treated. We also evaluated the clinical and laboratory changes observed for both preparations. Using the reduced dose protocol, TSH levels > 30 mIU/l were reached within 6 and 8 weeks in 84.6 and 100% of the patients, respectively. T4 withdrawal was associated with more common symptoms of hypothyroidism and elevation of creatine kinase (CK) and LDL cholesterol. The T4 dose reduction protocol proved to be useful for Tg stimulation and ablative therapy, without the complication of severe hypothyroidism or the cost of recombinant TSH.

Managing thyroid cancer without thyroxine withdrawal

A suspensão da tiroxina (T4) ou o TSH recombinante são usados para a estimulação da tireoglobulina (Tg), para o mapeamento de corpo inteiro (MCI) e para o tratamento com 131Iodo em pacientes com carcinoma tireoideano. Esse estudo avaliou um protocolo de redução de dose do T4 como alternativa para o preparo desses pacientes. Cinquenta e um pacientes submeteram-se à suspensão total de T4 para o MCI e a medida de Tg. Tratamento com T4 foi então reinstituído e mantido até que o TSH atingisse níveis < 0.3 mUI/l. A dose de T4 foi então dominuída para 0,8 µg/kg/dia e o TSH medido semanalmente. A Tg foi analisada quando o TSH estava > 30 mUI/l. Pacientes diagnosticados com a doença na fase inicial da avaliação foram tratados. Nós também avaliamos as alterações clínicas e laboratoriais observadas para ambos os preparos. Usando o protocolo de redução de dose, níveis de TSH > 30 mUI/l foram atingidos em 6 e 8 semanas em 84,6 and 100% dos pacientes, respectivamente. A suspensão do T4 esteve associada com sintomas mais comuns de hipotireoidismo e com elevação da creatino- quinase (CK) e LDL-colesterol. O protocolo de redução da dose de T4 mostrou-se útil para a estimulação da Tg e terapia ablativa, sem apresentar as complicações do hipotireoidismo severo ou chegar ao custo do TSH recombinante.

Outcome of ablation of thyroid remnants with 100 mCi (3.7 GBq) iodine-131 in patients with thyroid cancer.

A retrospective study was conducted on 186 patients with differentiated thyroid cancer without metastases who received an ablative dose of 100 mCi (3.7 GBq) iodine-131 after total thyroidectomy. Six months to one year after ablation, 155/186 patients (83%) had a negative scan. Diagnostic scanning with 5 mCi (185 MBq) performed 72 h or 3 months before ablation did not interfere with treatment success compared to patients not submitted to pre-therapy scanning. Pre-ablation cervical uptake values < 2% were associated with a higher ablation efficacy (94%), from 2 to 5% showed 80% success and values > 5%, 60% (p < 0.05). There were no significant differences between the responsive and no responsive groups in terms of age, sex, histological type or size of the primary tumor. 11% of the patients with low stimulated Tg (< 2 ng/ml) presented discrete thyroid bed uptake on follow-up diagnostic scan (< 0.5%) without definitive residual disease and 89% had negative uptake on scan. The patients with Tg > 2 ng/ml presented thyroid bed (10/12) or ectopic (2/12) uptake on follow-up diagnostic scan. An ablative dose of 100 mCi shows a high rate of efficacy, especially when cervical uptake is < 2%; no difference was noted between patients assessed by scan within 72 h or 3 months before treatment and those not scanned; follow-up diagnostic scan can be avoided in low risk patients with stimulated Tg < 2 ng/ml.

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

OBJETIVO: Determinar a interferência de uma dose traçadora de 5mCi de 131I. 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). CONCLUSAO: Esses resultados indicam que o rastreamento diagnóstico usando uma dose de 5mCi de 131I não interefere com a captação da dose ablativa ou com a eficácia do tratamento quando a ablação é realizada dentro de 72h.

Ablative treatment of thyroid cancer with high doses of 131I without pre-therapy scanning.

OBJECTIVE: To determine the success of ablative treatment using fixed high doses of 131I in patients with thyroid cancer. METHODS: A retrospective study was conducted on 274 patients who received ablative treatment without previous scanning, with the dose being based on surgical staging: stage I patients (tumour restricted to the thyroid) received 3.7 GBq, and stage II (lymph node metastases) and stage III patients (extra-thyroid invasion) were treated with 5.5 GBq. Successful treatment was defined as a negative control scan. RESULTS: One hundred and sixty patients were classified as stage I and 114 as stages II or III. Forty-six patients presented ectopic uptake on post-therapy scans (10% in stage I and 26% in stage II or III). Among stage I patients, the efficacy of treatment was 78.7%. A 47% failure rate was associated with metastases, and among patients without metastases who did not respond to treatment, thyroid bed uptake >5% on post-therapy scans was observed in 61%. Patients with stage II or III showed 62.2% efficacy. Twenty-three of the 43 (53%) unsuccessfully treated patients in this group had metastases and of the 20 patients without metastases, 14 (70%) presented thyroid bed uptake >5%. There were no differences between the responsive and non-responsive groups in terms of age, gender, histological type or size of the primary tumour. CONCLUSION: Empirical treatment presented 72% efficacy (higher in stage I) and failure was associated with the presence of metastases and large thyroid remnants; factors that can be evaluated by pre-therapy whole-body scanning.

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

OBJECTIVE: To determine the stunning effect of a tracer dose of 5 mCi 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 100 mCi and those with metastases received 200 mCi. 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 patients cases (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 5 mCi iodine-131 dose does not interfere with uptake of the ablative dose or with treatment efficacy when ablation is performed within 72 h.

Efficacy of low and high 131I doses for thyroid remnant ablation in patients with differentiated thyroid carcinoma based on post-operative cervical uptake.

OBJECTIVE: The aim of this study was to determine the efficacy of low (1110 MBq (30 mCi)) and high (3700 MBq (100 mCi)) 131I doses on the ablation of post-surgical remnants in patients with thyroid cancer based on the measurement of post-operative cervical uptake. METHODS: The study was conducted on 155 patients without metastases after thyroidectomy who received a 1110 or 3700 MBq ablative dose and who were assessed by pre-therapy cervical uptake. The patients were divided into six groups according to the uptake result and the dose received. Successful therapy was defined as a negative scan 6 months to 1 year after ablation. RESULTS: Ablative therapy was successful in 90% of patients with uptake <2% who received the 1110 MBq dose (n=30) and in 92.5% of patients who received the 3700 MBq dose (n=40), P=0.95. In the group with uptakes ranging from 2% to 5%, successful therapy was observed in 65% of patients receiving 1110 MBq (n=20) and in 86.6% of patients receiving 3700 MBq (n=30), P=0.14. In patients with uptake >5%, a 46.6% success rate was obtained for the 1110 MBq dose (n=15), while efficacy was 70% in patients receiving 3700 MBq (n=20), P=0.16. CONCLUSION: This study demonstrated the efficacy of low doses in patients with lower remnants after surgery (uptake <2%), the inverse correlation between uptake and ablation efficacy with low and high doses, and the usefulness of the measurement of cervical uptake for the definition of the ablative 131I dose.