Predictive value of psTg on the excellent response to 131I treatment in patients with functional lymph node metastases after papillary thyroid carcinoma surgery / 中华核医学与分子影像杂志

ABSTRACT

Objective:To explore the predictive value of preablative stimulated thyroglobulin (psTg) level before 131I treatment on the excellent response (ER) to 131I treatment in patients with functional residual lymph node metastasis without distant metastasis after papillary thyroid carcinoma (PTC) surgery. Methods:From March 2011 to June 2015, 72 patients (22 males, 50 females, age 14-76 (46.5±14.4) years) who were diagnosed with functional lymph node metastasis without distant metastasis at the time of their first 131I treatment after total thyroid bilobectomy + lymph node dissection performed in the Affiliated Cancer Hospital of Zhengzhou University were retrospectively included, and their serum thyroglobulin antibody (TgAb) levels were normal. Patients were divided into ER group and non-ER group according to the treatment response assessment system. Independent sample t test, χ2 test, and Mann-Whitney U test were used to compare the basic clinical characteristics between the two groups, and then multivariate logistic regression was performed. The ROC curve was employed to evaluate the predictive value of psTg and lymph node size in 131I treatment response. Results:The treatment responses of 44 patients were ER, and those of 28 were non-ER. The differences in gender, age, clinical stage, number and location of postoperative metastatic lymph nodes between ER and non-ER groups were not statistically significant ( t=0.82, χ2 values 0.16-2.60, all P>0.05), while there were significant differences in American Thyroid Association (ATA) initial risk stratification ( χ2=33.38), lymph node size ( U=296.50) and psTg ( U=111.00, all P<0.001). PsTg (odds ratio ( OR)=0.047, 95% CI 0.004-0.500, P=0.011) and lymph node size ( OR=0.146, 95% CI 0.032-0.666, P=0.013) were independent factors affecting ER, whereas ATA initial risk stratification was not an independent factor ( OR=0.266, 95% CI 0.051-1.390, P=0.116). AUCs for psTg and lymph node size were 0.904 and 0.873, respectively. The cut-off value of psTg was 20.05 μg/L with the sensitivity and specificity of 96.4%(27/28) and 75.0%(33/44) respectively, and lymph node size was 0.75 cm with the sensitivity and specificity of 78.6% (22/28) and 81.8% (36/44) respectively. Conclusion:PsTg can be used to predict 131I outcomes in patients with functional lymph node metastases after PTC, and lymph node size also has effect on ER.