Abstract:
Objective To investigate the therapeutic efficacy and influencing factors of postoperative 131I treatment for pulmonary metastatic differentiated thyroid cancer (DTC).
Methods The clinical data of 108 patients with pulmonary metastatic DTC who were admitted to the Affiliated Hospital of Qingdao University from January 1993 to March 2021 were retrospectively analyzed. There were 42 males and 66 females, with a median age of 54.3(17–77) years old and a median follow-up of 4.19(1.13–23.45) years. Before and after 131I treatment, serum thyroid-stimulating hormone (TSH), thyroglobulin (Tg), and thyroglobulin antibody (TgAb) levels were detected; moreover, chest CT, 131I whole-body scan, neck ultrasound, and other imaging examinations were performed to evaluate the progression of lung metastases. The efficacy of 131I treatment was evaluated following the Response Evaluation Criteria for Solid Tumors (RECIST) 1.1 and the change in serum stimulated thyroglobulin (sTg) level before 131I treatment. On the basis of the efficacy of 131I treatment, the patients were divided into the disease control group and disease progression group. The ratio of sTg level to TSH level before the second 131I treatment compared with the first 131I treatment was calculated (△sTg/TSH). Chi-square test and Kruskal-Wallis rank sum test were used for univariate analysis of the clinical pathological characteristics of the two groups. Logistic regression was used for multivariate analysis of the indicators with statistically significant differences in the above univariate analysis. The predictive value of △sTg/TSH for disease progression was evaluated by receiver operating characteristic (ROC) curve and the optimal cut-off value.
Results Among 108 patients, 86 patients (79.6%) were in the disease control group after surgery and 131I therapy. A total of 22 patients (20.4%) were in the disease progression group. The results of univariate analysis showed significant differences between the two groups in age, pathological type, long diameter of the primary DTC lesion, serum sTg level before the first 131I treatment, △sTg/TSH, long diameter of lung metastases, iodine uptake of lung metastases, and diagnosis time (H=−3.194, χ2=19.142, H=−2.888, −2.499, −4.140, χ2=15.380, 4.069, 10.362; all P<0.05). Multivariate logistic regression analysis showed significant differences in the pathological type, △sTg/TSH, and long diameter of lung metastases between the two groups (B=3.059, 0.048, 4.140; OR=21.314, 1.050, 62.798; 95%CI: 1.112–408.369, 1.009–1.092, 1.528–2 581.064; all P<0.05). The optimal cut-off value of △sTg/TSH for predicting disease progression was −0.785%, and the area under the curve of the ROC was 0.809(95%CI: 0.701–0.917, P<0.001).
Conclusion Pathological type, △sTg/TSH, and long diameter of lung metastases are independent risk factors affecting the efficacy of postoperative 131I treatment and predicting the progression of pulmonary metastatic DTC.