A Prospective Study Showing an Excellent Response of Patients with Low-Risk Differentiated Thyroid Cancer Who Did Not Undergo Radioiodine Remnant Ablation after Total Thyroidectomy.
OBJECTIVE
To prospectively evaluate the outcome of patients with low-risk papillary thyroid carcinoma treated with total thyroidectomy (TT) who did not undergo radioiodine remnant ablation (RRA).


METHODS
We prospectively followed up 57 patients; 3 months after TT, thyroglobulin (Tg) assessment and neck ultrasonography (US) were performed while patients were taking l-T4, presenting suppressed TSH. Six months after TT, patients underwent stimulated Tg testing and whole-body scan (WBS) after recombinant TSH (rhTSH). Then, 18 months after TT, the patients were evaluated by neck US and Tg under TSH between 0.5 and 2.0 mIU/ml. Two years after TT, we performed another rhTSH assessment, measuring Tg and making a WBS. The patients were then annually monitored with neck US and Tg measurement under TSH between 0.5 and 2.0 mIU/l for 36-84 months.


RESULTS
Neck US of all patients, 3 months after TT, presented no evidence of abnormal residual tissues or metastatic lymph nodes (negative neck US); at this time, the mean Tg level was 0.42 ng/ml. Six months after surgery, after rhTSH, the mean thyroid bed uptake was 1.82%, and Tg levels ranged from 0.10 to 22.30 ng/ml (mean, 2.89 ng/ml). The patients were followed up without any sign of recurrence (negative neck US and stable or decreasing Tg levels). During the ongoing follow-up, the Tg trend was stable or decreasing, independently of the initial suppressed or stimulated Tg level, or WBS uptake.


CONCLUSIONS
In patients with low-risk differentiated thyroid cancer, who were operated by TT and who did not undergo RRA, an excellent response to treatment may be confirmed by annual neck US and Tg trend.
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Carolina C P S
CC
Janovsky
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Rui M B
RM
Maciel
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Cleber P
CP
Camacho
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Rosalia P
RP
Padovani
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Claudia C
CC
Nakabashi
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Ji H
JH
Yang
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Eduardo Z
EZ
Malouf
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Elza S
ES
Ikejiri
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
M Conceição O C
MC
Mamone
Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Jairo
J
Wagner
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Danielle M
DM
Andreoni
Thyroid Diseases Center and Laboratory of Molecular and Translational Endocrinology, Division of Endocrinology, Department of Medicine, Escola Paulista de Medicina, Universidade Federal de São Paulo, São Paulo, Brazil; Thyroid Diseases Center, Instituto Israelita de Ensino e Pesquisa Albert Einstein, São Paulo, Brazil.
Rosa Paula M
RP
Biscolla
Low-risk thyroid carcinoma; Neck ultrasound; Radioiodine remnant ablation; Thyroglobulin; Thyroglobulin temporal trend