title: Day 3 thyroglobulin ≤ 1 ng/ml after recombinant human TSH just prior to radioactive iodine is predictive of low risk for persistent/recurrent disease in patients with papillary thyroid carcinoma.
abstract: We evaluated the negative predictive value (NPV) of thyroglobulin obtained 24 h after the second recombinant human TSH (rhTSH) ampoule (Tg-D3), before ablation with (131)I, for persistent/recurrent disease (PRD) in low/intermediate risk patients with papillary thyroid carcinoma. One hundred and one patients with Tg-D3 ≤ 1 ng/ml without anti-Tg antibodies (TgAb) were selected. Post-therapy whole-body scanning was negative for metastases in 98 (97 %) patients, and three patients showed discrete ectopic cervical uptake, but no corresponding disease was detected by neck ultrasound or computed tomography. One year after ablation, 98 (97 %) patients were free of the disease. Three patients had stimulated Tg >1 ng/ml, but no metastases were detected by the imaging methods. During follow-up (median 50 months), tumor recurrence was observed in only one patient. Thus, the NPV of Tg-D3 ≤ 1 ng/ml for PRD was 99 %. Among the 101 patients with Tg-D3 ≤ 1 ng/ml, Tg obtained 48 h after ablation (Tg-D5) continued to be ≤ 1 ng/ml in 56, and 45 had Tg-D5 >1 ng/ml. None of these 45 patients had PRD. In conclusion, Tg-D3 ≤ 1 ng/ml had a high NPV for PRD in patients without TgAb or known persistent disease and who are not at high risk. In these patients, Tg-D5 >1 ng/ml is more likely to reflect actinic damage to the remnant thyroid tissue rather than persistence of significant normal or tumor tissue.
authors.affiliation: Postgraduate Program and Endocrinology Service, Instituto de Ensino e Pesquisa da Santa Casa de Belo Horizonte, Rua Domingos Vieira, 590, Santa Efigênia, Belo Horizonte, MG, 30150-240, Brazil, pedrowsrosario@gmail.com.
authors.forename: Pedro W
authors.initials: PW
authors.lastname: Rosario
authors.forename: Thássio Leonardo
authors.initials: TL
authors.lastname: Siman
authors.forename: Maria R
authors.initials: MR
authors.lastname: Calsolari
mesh_terms: D055011:Ablation Techniques; D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D014408:Biomarkers, Tumor / Q000097:blood*; D002277:Carcinoma / Q000097:blood* / Q000628:therapy*; D002291:Carcinoma, Papillary; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging; D009364:Neoplasm Recurrence, Local / Q000097:blood*; D011237:Predictive Value of Tests; D011859:Radiography; D013954:Thyroglobulin / Q000097:blood*; D000077273:Thyroid Cancer, Papillary; D013964:Thyroid Neoplasms / Q000097:blood* / Q000628:therapy*; D057073:Thyrotropin Alfa / Q000627:therapeutic use*; D014463:Ultrasonography; D051598:Whole Body Imaging; D055815:Young Adult
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D057073:Thyrotropin Alfa; D013954:Thyroglobulin