[Significance of Dynamic Risk Assessment in the Follow-up of Non-distant Metastatic Differentiated Thyroid Cancer Patients with Intermediate and High Risk].

Objective To tailor the subsequent treatment and follow-up strategy,this study dynamically assessed the response to initial therapy in non-distant metastatic differentiated thyroid cancer (DTC) patients with intermediate and high risk. Methods A total of 184 non-distant metastatic DTC patients (intermediate-risk 111 cases and high-risk 73 cases) were retrospectively enrolled in this study. Based on the results of initial response assessment (6-12 months after initial therapy),patients were divided into two groups:excellent response (ER) group (n=113) and non-excellent response (non-ER) group (n=71). We compared the differences in clinicopathological features between these 2 groups and evaluated the changes of dynamic response to therapy at the initial and final assessments after initial therapy in all patients. Results Compared with the ER group,the non-ER group showed a larger tumor size (U=2771.500,P=0.000),higher proportion of extrathyroidal invasion (χ 2=4.070,P=0.044),and higher preablative-stimulated thyroglobulin levels (U=1367.500,P=0.000). ER was achieved in 31% of patients in the initial non-ER group [including indeterminate response (IDR) and biochemical incomplete response (BIR)] at the final follow-up only by thyroid stimulating hormone (TSH) suppression therapy,among which 63.6% were with intermediate risk (especially the patients with IDR) and 36.4% at high risk. In addition,5.2%(6/113) of patients in the initial ER group were reassessed as IDR,BIR,or even structural incomplete response at the end of the follow-up (among which one patient developed into cervical lymph node recurrence,as confirmed by pathology);the TSH level in these patients fluctuated at 0.56-10.35 µIU/ml and was not corrected in time during the follow-up after initial therapy. Conclusions Some of non-distant metastatic DTC patients with intermediate and high risks who presented initial non-ER may achieve ER only by TSH suppression therapy over time;in contrast,the patients presented initial ER may develop into non-ER without normalized TSH suppression therapy. The dynamic risk assessment system may provide a real-time assessment of recurrence risk and tailor the subsequent treatment and follow-up strategies.