Endocrine Abstracts

Objectives: DTC has a favorable clinical course. A small percentage of patients undergoing surgery and RAI ablation may have local disease persistence and further therapeutic interventions may be needed such as further RAI administration following or not a second surgery. We investigated whether additional therapeutic interventions may be beneficial for the clinical course in DTC patients with disease persistence.

Methods: 812 DTC patients (men 25.7%, age at diagnosis 42.4±15.5 yrs) who received RAI ablation were followed-up in our department for 1–44 yrs (median 3 yrs). 206 of them received further RAI treatment with or without additional cervical surgery. They were classified in 3 groups according to the treatment modality that was followed: RAI-only (n=47, 22.8%), RAI+Surgery (n=86, 41.7%) multiple-interventions group (n=73, 35.4%). Clinical and histological characteristics were compared between groups.

Results: One year after diagnosis and before further intervention, stimulated thyroglobulin levels (sTG, median (IQR)) were in the groups RAI-only 4.9(23) vs RAI+surgery 6.7(47) vs multiple-interventions 62(179) ng/mL (P=0.01). After the additional interventions sTG changed to 5.3(26), 2.4(21), 33(143) respectively in the 3 groups (P<0.001). Patients in the RAI-only group showed less frequently disease remission compared to RAI+Surgery group (24.4% vs 43.5%, P<0.001). The occurence of distant metastases during follow up was higher in RAI-only group (33.3% vs 16.0%, P=0.002). Age at diagnosis, histology type, tumour size, multifocality, presence of lymph node infiltration, capsular invasion, soft tissue invasion, did not differ significantly between groups. The 10-year probability of lack of progression of disease was: RAI-only 67.4% vs RAI+Surgery 89.5% (x²=18.06, P<0.001). Disease progression, RAI refractory DTC and distant metastases were more prevalent in the group of multiple interventions (P<0.001).

Conclusions: In DTC patients with disease persistence a second RAI administration without prior surgical intervention may not be beneficial in the majority of cases. Surgical removal of the metastatic disease prior to RAI administration could be a better therapeutic option for these patients.