Comparative evaluation of recombinant human thyrotropin-stimulated thyroglobulin levels, 131I whole-body scintigraphy, and neck ultrasonography in the follow-up of patients with papillary thyroid microcarcinoma who have not undergone radioiodine therapy.
BACKGROUND
Although the prognosis of papillary thyroid microcarcinoma (PTMC) is usually excellent, the optimal follow-up strategy has never been investigated.


OBJECTIVE
The objective of the study was to investigate the role of neck ultrasonography (US), whole-body scintigraphy (WBS), and serum thyroglobulin levels (Tg) after recombinant human (rh) TSH in the follow-up of very low-risk PTMC patients.


METHODS
The study was a 5-yr observational study based on a 6- to 12-month follow-up after near total thyroidectomy.


METHODS
The study population consisted of ambulatory patients.


METHODS
Eighty consecutive patients diagnosed with PTMC, who had not undergone postoperative radioiodine treatment because of unifocal tumor without lymph node metastases and who did not have anti-Tg antibodies, were included.


METHODS
WBS and Tg after both rhTSH and neck US were measured.


RESULTS
rhTSH-Tg was 1 ng/ml or less in 45 (Tg-) and more than 1 in 35 (Tg+) patients. WBS showed no pathological uptake in any patient. US identified node metastases in two Tg (+) and one Tg (-) patients. rhTSH-Tg levels positively correlated with thyroid bed iodine uptake (r = 0.40, P < 0.0001). To date (32 +/- 13 months after surgery), all node-negative patients have undetectable Tg levels on LT(4) treatment and negative US.


CONCLUSIONS
For the initial follow-up of PTMC patients without risk factors and anti-Tg antibodies and who did not undergo radioiodine treatment: 1) WBS is useless; 2) US is highly sensitive in detecting node metastases; and 3) detectable rhTSH-Tg levels mainly depend on small normal tissue remnants. In this subgroup of PTMC patients, neck US might be regarded as a primary tool for the initial follow-up.
Torlontano
Massimo
M
Units of Endocrinology, Istituto di Ricovero e Cura a Carattere Scientifico Casa Sollievo della Sofferenza, 71013 S. Giovanni Rotondo, Italy. m.torlontano@tin.it
Crocetti
Umberto
U
Augello
Giovanni
G
D'Aloiso
Leonardo
L
Bonfitto
Nazario
N
Varraso
Antonio
A
Dicembrino
Franca
F
Modoni
Sergio
S
Frusciante
Vincenzo
V
Di Giorgio
Anna
A
Bruno
Rocco
R
Filetti
Sebastiano
S
Trischitta
Vincenzo
V
D000328:Adult; D002291:Carcinoma, Papillary / Q000175:diagnosis* / Q000000981:diagnostic imaging; D005260:Female; D015902:Gamma Cameras; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D011877:Radionuclide Imaging; D011994:Recombinant Proteins; D012008:Recurrence; D013954:Thyroglobulin / Q000097:blood; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging; D013972:Thyrotropin; D014463:Ultrasonography; D014915:Whole-Body Counting
D007457:Iodine Radioisotopes; D011994:Recombinant Proteins; D013972:Thyrotropin; D013954:Thyroglobulin