Seguimento de pacientes de alto risco com carcinoma diferenciado de tireóide sem doença persistente após a terapia inicial

Abstract

This study evaluated the follow-up of high-risk patients with thyroid cancer after initial therapy. A total of 125 high-risk patients (tumor >4 cm and/or extrathyroid invasion and/or lymph node metastases, and age >45 years), with complete resection of the tumor, were selected. All patients underwent total thyroidectomy and ablation with (131)I[3.7-5.5 GBq (100-150 mCi)]. Eighteen patients (14.8%) presenting metastases on post-dose whole-body scan (RxWBS) were excluded. The negative predictive value of stimulated Tg < or =1 ng/ml in combination with neck US during first assessment (612 mo. after ablative therapy) was 96.2% for the absence of recurrence up to 5 years. This value increased to 98.7% when adding WBS performed with 185 MBq (5 mCi) (131)I (DxWBS). The positive predictive value (PPV) of stimulated Tg >1 ng/ml was 52% for the detection of the presence of metastases up to 5 years; however, considering only patients with initially negative DxWBS and US, the PPV was 19% (9% if Tg of 110 ng/ml vs. 40% if Tg >10 ng/ml). Tg levels decreased spontaneously in patients with stimulated Tg >1 ng/ml during first assessment, negative US and DxWBS, and no recurrence during follow-up, with Tg being undetectable in half these patients at the end of 5 years. Twenty patients presented uptake in the thyroid bed upon DxWBS during the first year after ablative therapy, with stimulated Tg and US being negative, and were not treated with 131I; these patients did not relapse and no uptake on DxWBS was observed in 60% after 5 years. Recurrence after 5 years was only 1.3% in patients without apparent disease (negative US and DxWBS) and stimulated Tg <1 ng/ml. An algorithm for the follow-up of high-risk patients after initial therapy is presented in this study.

2013 European Thyroid Association Guidelines for Cervical Ultrasound Scan and Ultrasound-Guided Techniques in the Postoperative Management of Patients with Thyroid Cancer

“…- If no detailed preoperative US is available to detect the persistence of any LN metastases [47,48,49]. …”

Utilidade da tomografia de emissão de pósitrons com fluoro-deoxiglicose (FDG-PET) na avaliação do câncer de tireóide: uma revisão sistemática

“…Ocasionalmente, tornam-se necessárias US abdominal, TC e MRI. A dosagem da Tg estimulada (através do TSH recombinante humano ou da suspensão da levotiroxina) juntamente com a US cervical são bastante sensí-veis na detecção das metástases e recorrências (30). Contudo, a presença de anticorpos anti-tireoglobulina, bem como a ocorrência de metástases loco-regionais mínimas diminuem a acurácia diagnóstica da dosagem da Tg na detecção de metástases, o que se torna mais preocupante quando a cintigrafia de corpo inteiro com 131 I é negativa.…”