Analysis Of The Efficacy And Factors Of Radioactive¹³¹I On Differentiated Thyroid Carcinoma After Operation

Objective To investigate the efficacy of the first radioiodine ablation residual thyroid after operation and metastasis of radioactive131I on differentiated thyroid carcinoma (DTC), and to analyze the influential factors for curative effect.Methods51patients of DTC after surgery, including48cases of papillary thyroid carcinoma,3cases of follicular thyroid carcinoma. Then patients were ablated of residual thyroid tissue with131I (2.96-5.55GBq) following an average of15.2months after surgery. After an average of6months, the patients took the second large doses of131I and then made131I whole body imaging, which showed thyroid gland location without residual thyroid tissue was considered a success for the first time of treatment of131I.40patients of DTC with metastasis, including35cases of papillary thyroid carcinoma,5cases of follicular thyroid carcinoma. All DTC patients were treated with1311undergoing three times or more. The mean doses of treatment for metastasis of neck lymph node, mediastinal lymph node, lung, bone were168.21±23.53mCi,169.84±24.20mCi,178.70±22.72mCi,194.88±25.96mCi. Overall effect of metastasis were divided into cured, improved or stable, invalid or deteriorated. The curative effect of local metastasis consisted of eliminating, improved or stable, invalid or progress. Univariate analysis used t-test, ANOVA, non-parametric tests, chi-square test, and regression analysis used Binary Logistic and Ordinal Logistic.Result22of51patients(43.1%) had achieved successful thyroid remnant ablation at first therapy of131I,29patients were unsuccessful(56.9%). Univariate analysis revealed that the volume of thyroid residue (X2=4.965, P=0.026),the interval time from the first surgery to the first131Ⅰ ablative treatment (Z=-2.631, P=0.009), the level of TSH(Z=-2.149, P=0.032), the level of Tg(Z=-2.815, P=0.005)and whether to metastasize (Fisher’s Exact Test, P=0.002) at the time of131Ⅰ therapy were the important influence factors of131Ⅰ successful ablation rate. Binary Logistic regression analysis (αentry=0.10, αremoval=0.15) showed that the level of TSH (Wald=4.209, P=0.040), Tg (Wald=4.563, P=0.033) as influence factors of131Ⅰ successful ablation rate. In40cases of DTC with metastasis after treatment, cured cases were9cases, the cure rate was22.5%, improved or stabled cases were26cases, the total efficiency was87.5%, invalid or deteriorated cases were5patients. Single factor analysis showed that age(H=7.072, P=0.029), the average dose(F=3.809, P=0.031), the dose of average treatment(F=5.056, P=0.011), the site of metastasis (X2=8.687, P=0.040), the level of serum TSH before the first therapy (H=8.874, P=0.012), the level of serum Tg before the first treatment (H=11.343, P=0.003) were the factors of131I efficacy on treating DTC with metastasis. According to the results of regression analysis, age (Wald=5.014, P=0.025), the site of metastasis (Wald=5.559, P=0.018), the level of serum TSH before the first treatment (Wald=5.174, P=0.023) had statistical significance.30cases of neck lymph node metastasis, the rate of elimination was50%, the total effective rate was90%,3cases were invalid or progressed, and the mode of operation (X2=10.281, P=0.013), the level of serum TSH before the first therapy (H=3.650, P=0.040), the level of serum Tg before the first therapy(H=3.459, P=0.047) were the factors of131Ⅰ efficacy on neck lymph node metastasis.12cases of mediastinal lymph node metastasis, the rate of elimination was16.67%, the total effective rate was83.34%,2cases were invalid or progressed.21cases of patients with pulmonary metastases, the rate of elimination was9.52%, the total effective rate was76.19%,5were invalid or progressed. The level of serum TSH before the first therapy (H=8.200, P=0.017), the level of serum Tg before the first therapy (H=8.015, P=0.007) were the factors of131Ⅰ efficacy on treating DTC with lpulmonary metastases.5patients with bone metastasis, no cases were eliminated,2patients were stabled,3cases were invalid or progressed.Conclusion The successful rate of thyroid remnant ablation at first therapy of131I was43.1%.The less the volume of thyroid residue,the shorter the interval time from the first surgery to the first131I ablative treatment,the higher level of blood TSH, the lower level of Tg and no extrathyroidal metastasis were accompany with the higher treatment success rate. The level of blood TSH and Tg were important. The total efficiency of131I treatment of DTC with metastases was87.5%, the patients who under60years old, no distant metastasis, the level of serum TSH before the first therapy≥30uIU/L can improve the131I effect of DTC with metastases. The mode of operation, the level of serum TSH and Tg before the first therapy were the factors of131I efficacy on neck lymph node metastasis.The level of serum TSH and Tg before the first therapy were the factors of131I efficacy on treating DTC with lpulmonary metastases.