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A low postoperative nonstimulated serum thyroglobulin level excludes the presence of persistent disease in low‐risk papillary thyroid cancer patients: implication for radioiodine indication
Author(s) -
Rosario Pedro W.,
Mourão Gabriela F.,
Siman Thassio Leonardo,
Calsolari Maria Regina
Publication year - 2015
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12668
Subject(s) - medicine , thyroid carcinoma , thyroglobulin , thyroidectomy , papillary thyroid cancer , thyroid cancer , gastroenterology , endocrinology , thyroid , urology
Summary Objective To evaluate the presence of persistent disease, including on post‐therapy whole‐body scan (Rx WBS ), in low‐risk patients with papillary thyroid carcinoma ( PTC ) >1 cm who have low nonstimulated thyroglobulin (Tg) (measured with a sensitive assay), negative anti‐Tg antibodies (TgAb) and neck ultrasound ( US ) showing no metastases after total thyroidectomy. Patients We studied 154 patients with PTC >1 cm classified as low risk, who had US without metastases, negative TgAb, nonstimulated Tg ≤ 0·25 ng/ml and TSH ≤2 mIU/l about 3 months after total thyroidectomy. Results Tg measured immediately before 131 I was ≤1 ng/ml in 89·5% of the patients and >1 ng/ml in 10·5%. None of the patients showed ectopic uptake on Rx WBS . Uptake in the thyroid bed was observed in 146 (94·8%) patients and was ≤2% in all of them. In the control assessment 9–12 months after ablation, stimulated Tg (sTg) ≤1 ng/ml was achieved in 150 patients (97·4%). Only one patient had sTg >2 ng/ml (2·5 ng/ml) and none of the patients had apparent disease detected by imaging methods. During further short‐term follow‐up after control assessment (median of 24 months), none of the patients had tumour recurrence. Conclusions The combination of nonstimulated Tg ≤0·25 ng/ml, negative TgAb and US without metastases after thyroidectomy rules out the presence of persistent disease (including on Rx WBS ) in low‐risk patients with PTC >1 cm. This demonstration weakens the indication of ablation with 131 I in these cases.