Revisitando a tireoglobulina sérica no seguimento de pacientes com carcinoma diferenciado de tireóide

Abstract

RESUMOEste estudo avaliou a tireoglobulina (Tg) sérica dosada em hipotireoidismo em 207 pacientes com carcinoma diferenciado de tireóide tratados com tireoidectomia total e ablação com radioiodo e anticorpos anti-Tg indetectáveis. O estadiamento da doença foi definido pelo exame clínico, Tg estimulada, varredura com radioiodo pré e/ou pós-terapia ablativa e outros métodos de imagem (RX, US, TC e varredura com sestamibi). O intervalo médio desde a terapia inicial foi de 2,3 anos. Dos pacientes, 153 (74%) não apresentavam doença evidente, 34 (16,4%) tinham metástases (Mt) cervicais ou mediastinais e 20 (9,6%) Mt distantes. O valor de 1ng/ml da Tg foi o que melhor discriminou pacientes com e sem doença aparente, com 100% de sensibilidade para Mt distantes, 88,2% para doença em leito tireoidiano ou linfonodos e especificidade de 88,8% para Mt de qualquer natureza, e 74,8% considerando apenas Mt distantes. Dos pacientes com Tg 1ng/ml, 2,8% apresentavam Mt cervicais. Doença cervical ou mediastinal representou 26% dos casos com valores de Tg entre 1 e 5ng/ml. Tg entre 5 e 10ng/ml foi associada a Mt distantes em 14,2% dos casos, os demais apresentavam Mt linfonodais. Mt distantes foram diagnosticadas em 51,3% dos pacientes com Tg >10ng/ml. Sugerimos a necessidade de US cervical mesmo em pacientes com Tg 1ng/ml; que pacientes com Tg <5ng/ml sejam investigados apenas com US cervical e TC de mediastino; e que a terapia empírica fique reservada aos casos com Tg no mínimo >5ng/ml. This study analyzed serum thyroglobulin (Tg) during hypothyroidism in 207 patients with differentiated thyroid carcinoma treated with total thyroidectomy and radioiodine ablation and undetectable anti-Tg antibodies. Disease staging was defined by clinical examination, stimulated Tg, pre-and post-ablative radioiodine scanning, and other imaging methods (X-Ray, US, CT and MIBI-scan). The average interval from initial therapy was 2.3 years. 153 patients (74%) had no evident disease, 34 (16.4%) presented neck/mediastinal disease, and 20 (9.6%) had distant metastases (Mt). The best cut-off for Tg was 1ng/ml, showing 100% sensitivity for distant Mt and 88.2% for local recurrence or lymph node Mt, and 88.8% specificity for any Mt and 74.8% for distant Mt. In patients with Tg <1ng/ml, 2.8% showed cervical lymph nodes Mt. Cervical or mediastinal disease were 26% of cases with Tg between 1 and 5ng/ml. Tg from 5 to 10ng/ml was associated to distant Mt in 14.2% of the cases and others showed lymph nodes Mt. In patients with Tg >10ng/ml, 51.3% presented distant Mt. We suggest the need for neck US even in cases with Tg <1ng/ml. In addition, patients with Tg levels <5ng/ml should be investigated by neck US and medi-

Use of radioguided surgery technique for the treatment of thyroid cancer recurrence: clinical, surgical and anatomopathological aspects

“…A similar study carried out by Tuncel et al in Turkey in 2019 showed increased TG levels in all patients 18 . Postoperative follow-up with measurement of TG levels is extremely sensitive and specific to identify the presence of tumor recurrence, because its values should not be detected in individuals who do not have thyroid tissue 25 . In the patients of the present study who presented TG levels equal to zero, diagnostic suspicion was verified by cervical US examination.…”