Endocrine Abstracts

Introduction: Differentiated thyroid cancers (DTC) are the most frequently occuring endocrine malignancies. The factors determine the recurrences and metastases are whole body scanning (WBS) and either suppressed or stimulated thyroglobulin (sTg) levels. The aim of this study to evaluate the preablative factors predict of radioiodine remnant ablation (RRA) therapy success.

Patients and methods: One hundred consecutive patients with DTC (94 papillary and six follicular) who had undergone total or near total thyroidectomy with no evidence of cervical lymph node and distant metastases were retrospectively evaluated. Stimulated serum TSH and sTg levels were measured before RRA therapy and 6–12 months later. All patients underwent RRA under hypothyroid conditions (TSH >30 μIU/ml). ¹³¹I was used 100 mCi as mean dose.

Results: Among patients with DTC the mean age was 49±11.2 years. 87 were females and 13 were males. Eleven patients not included the study because their anti-Tg levels were positive. Preablative Tg levels were higher in patients which 6th month control WBS was positive, but not statistically significant (5.0 (0.6–135.0) vs 1.3 (0.01–99.0), P=0.06). Among preablative antiTg positive patients, 6th month WBS involvement rate was significantly higher than negative individuals (44.4 vs 11.3%, P=0.024). If postablation WBS revealed multifocal uptake, the 6th month WBS is more likely to be positive (11/51 (21.6%) vs 2/38 (5.3%), P=0.037). There were no significant difference on age, tumor size, tumor type, multifocality, anti-Tg, preablative TSH, postablative TSH and sTg between WBS positive and negative patients.

Conclusion: Patients with DTC which had positive antiTg and multifocal involvement in postablative WBS, 6–12 months after ¹³¹I remnant radio iodine ablation therapy, revealed that involvement continues. In these patients antiTg levels may affect treatment success. Further studies are needed to evaluate factors determined RRA succes.