title: [Revisiting serum thyroglobulin in the follow-up of patients with differentiated thyroid carcinoma].
abstract: 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 1 ng/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 <1 ng/ml, 2.8% showed cervical lymph nodes Mt. Cervical or mediastinal disease were 26% of cases with Tg between 1 and 5 ng/ml. Tg from 5 to 10 ng/ml was associated to distant Mt in 14.2% of the cases and others showed lymph nodes Mt. In patients with Tg >10 ng/ml, 51.3% presented distant Mt. We suggest the need for neck US even in cases with Tg <1 ng/ml. In addition, patients with Tg levels <5 ng/ml should be investigated by neck US and mediastinal CT only, and empirical therapy should be limited to patients with a minimum Tg level >5 ng/ml.
authors.affiliation: Departamento de Tireóide, Serviço de Endocrinologia e Metabologia, Santa Casa de Belo Horizonte, Belo Horizonte, MG. cepcem.bhz@terra.com.br
authors.forename: Pedro Weslley S
authors.initials: PW
authors.lastname: Rosário
authors.forename: Ludmilla David
authors.initials: LD
authors.lastname: Cardoso
authors.forename: Tales Alvarenga
authors.initials: TA
authors.lastname: Fagundes
authors.forename: Alvaro Luís
authors.initials: AL
authors.lastname: Barroso
authors.forename: Eduardo Lanza
authors.initials: EL
authors.lastname: Padrão
authors.forename: Leonardo Lamego
authors.initials: LL
authors.lastname: Rezende
authors.forename: Saulo
authors.initials: S
authors.lastname: Purisch
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007037:Hypothyroidism / Q000097:blood / Q000209:etiology; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D012189:Retrospective Studies; D012680:Sensitivity and Specificity; D013954:Thyroglobulin / Q000097:blood*; D013964:Thyroid Neoplasms / Q000097:blood* / Q000150:complications
chemical_list: D013954:Thyroglobulin