| Differentiated thyroid carcinoma(DTC) is a higher degree of differentiation, which includes papillary carcinoma, follicular carcinoma and mixture of this two types. Both DTC and its metastasis reserve the function of thyroid follicular epithelial cells which can synthesize thyroglobulin(Tg).Tg is a glycoprotein which was produced by thyroid follicular epithelial cells and stored in thyroid follicles. Under normal circumstances Tg cycles inside thyroid follicular epithelial cell, only a trace overflowed into the blood spill with the release of thyroid hormones, and that will not produce antibodies. Overseas study confirmed that higher degree of differentiation of thyroid carcinoma is similar with thyroid follicular cells, which can synthesize or secrete Tg. Therefore, Tg can be used as indicators of DTC detection and treatment has been widely applied. Recent studies have found that serum Tg levels are affected by many factors, including anti-thyroglobulin antibodies are one of the most obvious factors. In the case of TgAb-positive, serum Tg concentration will be affected by increasing or decreasing, thus losing valuable of diagnosis. Therefore, when we use serum Tg level to evaluate the situation of DTC, the impact of TgAb must be considered in. It is reported that when Tg is negative and TgAb is positive, metastasis of thyroid carcinoma can be diagnosed, and TgAb can also be used as tumor markers in thyroid carcinoma. Production of TgAb can be affected by many factors, so there is no unified conclusion of TgAb to the significance of DTC patients yet.To this end, it has significant valuable to identify the monitoring role of serum Tg, TgAb levels to DTC patients who happens to meet recurrence and metastasis and clarify the relationship between Tg and TgAb.ObjectiveThe aim of this study is to evaluate the value of Tg and TgAb in diagnosing metastasis of differentiated thyroid carcinoma patients after surgery and 131I therapy, and discuss the relationship between Tg and TgAb.Meterials and Methods253 DTC patients after surgery were divided into group with metastasis and group without metastasis, according to pathology, diagnostic imaging (including 131I-SPECT tomography fusion imaging, CT, MRI, Ultrasound) and clinical follow-up. Group with metastasis include cervical or mediastinal metastasis, pulmonary metastasis, bone metastasis,etc.with or without thyroid remain. Group without metastasis incllude thyroid remains only or ablated completely.Serum Tg and TgAb value were measured by stimulate state in all patients, and part of those patients were measured by inhibitory state.Recovery experiment:Tg(+)TgAb(-),Tg(-)TgAb(+),Tg(-)TgAb(-) serum were prepaired. Tg recoverry rate was calculated by Tg(+)TgAb(-) serum blended with Tg(-)TgAb(+) serum and Tg(-)TgAb(-) serum.Results1. Remove all TgAb-positive patients. Total positive rate of Tg was 24.5%, positive rate of Tg with metastasis was 63.64% and that without metastasis was 10.8%. Tg values of group with metastasis and without metastasis is 256.73±339.78ug/L, 73.55±204.28ug/L. Value of Tg difference between metastasis group and non-metastasis group is statistically significant (t=-4.581, P<0.001).The sensitivity, specificity, accuracy, positive predictive value and negative predictive value of Tg in diagnosing metastasis with 1.4-78ug/L as standarded were 63.64%,89.77%,81.82%,73.13% and 84.95%.Tg values of stimulate state and inhibitory state is 236.27±348.66ug/L,42.75±188.27ug/L. Value of Tg difference between stimulate state and inhibitory state is statistically significant(t=2.306, P=0.026<0.05).2. Total positive rate of TgAb was 18.9%, positive rate of TgAb with metastasis was 11.69% and that without metastasis was 21.59%. TgAb values of group with metastasis and without metastasis is 153.96±550.52IU/mL,190.01±515.67IU/mL. Value of TgAb between metastasis group and non-metastasis group has no statistically significant difference (t=-0.514, P=0.608>0.05). Value of TgAb in cured or improved group tends to be low, while that in no change or severe group tends to be lift. Difference between these two groups is statistically significant (P＜0.001).3. With decrease of TgAb(+) concentration in mixture, Tg recovery rate in experimental group increased, while stay what it is in control group.Conclusion1. Tg is a sensitive tumor marker to differentiated thyroid carcinoma, high level of serum Tg value will indicate there exist recurrent or metastatic lesions;2. Positive of TgAb can't diagnose recurrent or metastatic of DTC, monitoring TgAb values dynamically decrease continuously may indicate condition improved, while increase of TgAb continuously indicates exacerbations.3. Tg and TgAb can interact each other when using Electrochemiluminescene immunoassay(ECLIA), high serum TgAb concentrations can reduce serum Tg concentration. |
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