Change of pre-ablative thyroid-stimulating hormone after thyroid hormone withdrawal and its response to 131I therapy in patients with low to intermediate risk differentiated thyroid cancer / 中华核医学与分子影像杂志

ABSTRACT

Objective To investigate the relationship between the change of pre-ablative TSH after thyroid hormone withdrawal(THW) and the response of subsequent 131I therapy in patients with low to intermediate risk DTC after total or near total thyroidectomy.Methods A total of 120 DTC patients (38 males,82 females,age (40.8±10.9) years) were enrolled in this retrospective study.Serial TSH levels determined on the day of THW and on the day of receiving 131I ablative therapy were monitored,which were marked as TSH1 and TSH2 accordingly.The THW duration (t) was recorded,the change of TSH was defined as △TSH and the change rate of TSH was calculated (V=△TSH/t).The responses to 131I therapy were classified as excellent response (ER),indeterminate response (IDR),biochemical incomplete response (BIR) and structural incomplete response (SIR) according to ATA guideline.According to the TSH2(mU/L) levels,patients were divided into G1 group (30≤TSH2＜60),G2 group (60≤TSH2＜90),G3 group (90≤TSH2＜ 120),G4 group (120≤TSH2＜150) and G5 group (TSH2 ≥ 150).Clinical and pathological features,THW duration,the change rate of TSH,residual thyroid,131 I dose and follow-up time were compared among these groups.In order to evaluate the relationship between response to 131I ablation and change rate of TSH,patients were divided into V1 group (V≤2.5),V2 group (2.5＜V≤5.0) and V3 group (V＞5.0),and their responses to 131I ablation were compared.Patients were classified into RI group (including ER and IDR)and R2 group (including BIR and SIR),the differences of clinical and pathological features,131I doses between the two groups were explored.Furthermore,logistic regression was performed to identify factors associated with BIR and SIR.Results Patients with male gender (x2=11.863),younger age (F =4.975),and faster TSH change rate (H =44.911) and lower thyroid residue (H =18.159) achieved a higher value of TSH2(all P＜0.05).G3 group presented the highest rate of ER (83.8％,31/37).The percentage of ER + IDR in V2 group was higher than those in V1 group and V3 group,which was 92.4％ (61/66),85.7％ (18/21) and 5/7,respectively,but the difference was not significant (U=407.5,P＞0.05).TSH2 level (OR=0.835) and pre-ablative Tg level (OR =1.196) were independent factors in predicting BIR and SIR (both P＜0.05).Conclusions The changing rate of TSH before 131 I ablation may not be associated with the response to 131I therapy in patient with low to intermediate risk DTC,while the level of TSH2 does.Patients with TSH2 ranging from 90 to 120 mU/L could be of help in achieving a better clinical response.