Predictive value of recombinant human TSH stimulation and neck ultrasonography in differentiated thyroid cancer patients.
BACKGROUND
Serum thyroglobulin (Tg) stimulation by recombinant human TSH (rhTSH), in combination with neck ultrasonography (US), is an important tool in the first follow-up of differentiated epithelial cell thyroid carcinoma (DTC) patients. The objective of this study was to investigate if a second rhTSH stimulation, performed 2-3 years later, is of clinical utility in the follow-up of these patients.


METHODS
One hundred and one consecutive ambulatory DTC patients were studied. The great majority of them (89/101) were low-risk patients, being stage I or II at tumor node metastasis (TNM) staging classification. All study patients had been treated by surgery and radioiodine ablation, and exhibited, at first rhTSH follow-up, either undetectable Tg (<or=1 ng/mL) (rhTSH1-Tg-, n = 89 patients considered as free of disease) or low Tg (>1-5 ng/mL) (rhTSH1-Tg+, n = 12 patients considered with uncertain prognosis), with no US evidence of residual disease. In all patients, serum Tg measurement after a second rhTSH stimulation and neck US were performed.


RESULTS
At the second follow-up, all 89 rhTSH1-Tg-patients showed a negative US, and Tg became low positive only in one case, whereas it remained undetectable in the other patients. The overall negative predictive value of rhTSH1-Tg- was, then, 98.9%. Out of the remaining 12 patients (i.e., rhTSH1-Tg+ patients), 2 showed disease persistence/recurrence (with a positive predictive value of rhTSH1-Tg+ of 16.7%) and 6 became Tg-.


CONCLUSIONS
A second rhTSH stimulation is useless in DTC patients who were rhTSH-Tg and imaging negative at first follow-up, while it is suggested in patients with detectable, although low, rhTSH-Tg levels at first follow-up: in the absence of clinical or US evidence of disease persistence, these patients should not be retreated by radioiodine, but simply scheduled for a later rhTSH stimulation.
Crocetti
Umberto
U
Unit of Endocrinology, Scientific Institute Casa Sollievo della Sofferenza, S Giovanni Rotondo, Italy.
Durante
Cosimo
C
Attard
Marco
M
Maniglia
Adele
A
Tumino
Salvatore
S
Bruno
Rocco
R
Bonfitto
Nazario
N
Dicembrino
Franca
F
Varraso
Antonio
A
Meringolo
Domenico
D
Filetti
Sebastiano
S
Trischitta
Vincenzo
V
Torlontano
Massimo
M
D000293:Adolescent; D000328:Adult; D000368:Aged; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D009333:Neck / Q000000981:diagnostic imaging*; D011237:Predictive Value of Tests; D011994:Recombinant Proteins; D013964:Thyroid Neoplasms / Q000175:diagnosis* / Q000000981:diagnostic imaging*; D013972:Thyrotropin; D014463:Ultrasonography
D011994:Recombinant Proteins; D013972:Thyrotropin