Xue Yang1, Jun Liang1, Tianjun Li1, Teng Zhao1, Yansong Lin1. 1. Department of Nuclear Medicine (X.Y., T.Z.,. Y.L.), Chinese Academy of Medical Sciences & Peking Union Medical College Hospital, Beijing, China; Department of Oncology (J.L.), Peking University International Hospital, Beijing, China; Department of Oncology (T.L.), the Affiliated Hospital of Qingdao University, Qingdao, Shandong Province, PRC.
Abstract
CONTEXT: Studies suggested a potential value of preablative stimulated thyroglobulin (ps-Tg) on predicting the recurrent and persistent diseases of differentiated thyroid cancer, whereas its correlations with therapeutic response remain uncertain. OBJECTIVE: To establish the correlation between ps-Tg and therapeutic response proposed in 2015 American Thyroid Association guidelines, and calculate a cutoff ps-Tg threshold for predicting a poor response. DESIGN/ SETTING: Patients who underwent total thyroidectomy and radioactive iodine therapy in a university hospital participated in this retrospective study. PATIENTS: Totally, 452 patients with differentiated thyroid cancer were followed for a median of 38 months and were divided into three groups in terms of ps-Tg level: group 1, less than 1 ng/ml (n = 82); group 2, 1-10 ng/ml (n = 173); and group 3, at least 10 ng/ml (n = 197). MAIN OUTCOME MEASURE: Clinical outcomes were assessed based on response to therapy restaging system, dividing responses into excellent, indeterminate, biomedical incomplete, and structural incomplete (SIR). RESULTS: Therapeutic responses could be obviously distinguished by different ps-Tg strata. SIR was identified in none of group 1, 1.73% of group 2, and 42.74% of group 3, respectively (χ(2) = 123.037, P < .001). A cutoff value of ps-Tg at 26.75 ng/ml was obtained by receiver operating characteristic curve for differentiating SIR from either excellent, indeterminate, or biomedical incomplete responses. The area under curve was 0.947 and negative predictive value was 96.99%. Ps-Tg was an independent predictive variable of SIR (odds ratio, 42.312; P < .001). CONCLUSIONS: Ps-Tg has a great performance in predicting therapeutic response and providing incremental value for decision making of radioactive iodine therapy, especially for patients with high ps-Tg level.
CONTEXT: Studies suggested a potential value of preablative stimulated thyroglobulin (ps-Tg) on predicting the recurrent and persistent diseases of differentiated thyroid cancer, whereas its correlations with therapeutic response remain uncertain. OBJECTIVE: To establish the correlation between ps-Tg and therapeutic response proposed in 2015 American Thyroid Association guidelines, and calculate a cutoff ps-Tg threshold for predicting a poor response. DESIGN/ SETTING:Patients who underwent total thyroidectomy and radioactive iodine therapy in a university hospital participated in this retrospective study. PATIENTS: Totally, 452 patients with differentiated thyroid cancer were followed for a median of 38 months and were divided into three groups in terms of ps-Tg level: group 1, less than 1 ng/ml (n = 82); group 2, 1-10 ng/ml (n = 173); and group 3, at least 10 ng/ml (n = 197). MAIN OUTCOME MEASURE: Clinical outcomes were assessed based on response to therapy restaging system, dividing responses into excellent, indeterminate, biomedical incomplete, and structural incomplete (SIR). RESULTS: Therapeutic responses could be obviously distinguished by different ps-Tg strata. SIR was identified in none of group 1, 1.73% of group 2, and 42.74% of group 3, respectively (χ(2) = 123.037, P < .001). A cutoff value of ps-Tg at 26.75 ng/ml was obtained by receiver operating characteristic curve for differentiating SIR from either excellent, indeterminate, or biomedical incomplete responses. The area under curve was 0.947 and negative predictive value was 96.99%. Ps-Tg was an independent predictive variable of SIR (odds ratio, 42.312; P < .001). CONCLUSIONS:Ps-Tg has a great performance in predicting therapeutic response and providing incremental value for decision making of radioactive iodine therapy, especially for patients with high ps-Tg level.