TITLE:
The Diagnostic Value of Serum TgAb in the Tg-Negative and TgAb-Positive DTC Patients after Successful Ablation
AUTHORS:
Qun Fan, Xinhui Su, Anren Kuang
KEYWORDS:
DTC, TgAb, Cut-Off Value
JOURNAL NAME:
Journal of Cancer Therapy,
Vol.7 No.12,
November
9,
2016
ABSTRACT: Objective:
The aim of this retrospective study was to evaluate diagnostic accuracy of
serum thyroglobulin antibody (TgAb) in thyroglobulin (Tg)-negative and TgAb-positive
(Tg-TgAb+) patients with differentiated thyroid carcinoma
(DTC). Method: We studied 341 patients with histologically confirmed DTC who
had undergone remnant ablation and showed Tg-TgAb+ assessed by electrochemiluminescence immunoassay (ECLIA). The cases were
divided into two groups, including recurrence group 119 cases and no evidence
of disease (NED) group 222 cases. Receiver operating characteristic (ROC) curve
analysis was carried out. The symmetric measures of the two diagnostic methods
(the golden standard and the diagnostic standard as serum TgAb level alone)
were analyzed using McNemar test and measure of agreement Kappa. Results: Serum
TgAb level (1381.292 ± 1017.221)
IU/ml of patients with recurrent group was
significantly higher than that (125.559 ± 314.047) IU/ml of NED group (P = 0.000 0.001). The area
under the ROC curve was 0.962 and its asymptotic 95% confidence interval (CI)
was (0.942, 0.982)
that was high statistical significance. The cut-off value of TgAb was
determined and interpreted at 246.695 IU/ml with
sensitivity (92.40%) and specificity (92.30%). McNemar test showed that the
diagnostic results of the two methods were not significant difference (P =
0.230 > 0.05).
Measure of agreement Kappa was 0.841, P = 0.000 0.001 that
showed the agreement of the two diagnostic methods was significant.
Conclusion: Serum TgAb is a useful tumor marker for recurrence in Tg-negative
and TgAb-positive DTC patients who underwent thyroidectomy and remnant
ablation. The cut-off value of TgAb is 246.695 IU/ml, that is to say, serum
TgAb level upon 246.695 IU/ml may be associated with the persistence or
recurrence of DTC.