Post-ablative serum thyroglobulin is an independent predictor of recurrence in low-risk differentiated thyroid carcinoma: a 16-year follow-up study

OBJECTIVE: To study whether post-surgical and/or post-ablative thyroglobulin (Tg) concentrations may serve as independent predictors of disease recurrence in patients treated for TNM stage I or II well-differentiated thyroid carcinoma (WDTC). DESIGN: An observational retrospective study with a median follow-up of 16 years (range 10-24). PATIENTS AND MEASUREMENTS: Post-operative and post-ablative Tg concentrations, age, tumour size, local infiltration and nodal metastasis at primary surgery as well as disease recurrences and cancer-specific deaths were evaluated in 495 low-risk (TNM stages I and II) patients, the majority of whom had total thyroidectomy and radioactive iodine remnant ablation as initial treatment. RESULTS: Fifty-one patients (10.3%) experienced disease recurrence during follow-up. In multiple logistic regression analysis, post-ablative Tg concentrations (odds ratio (OR) 3.72, confidence interval (CI) 1.71-8.05, P=0.0009) and local infiltration on primary surgery (OR 2.66, CI 1.03-6.90, P=0.04) were the only independent predictors of recurrence. CONCLUSIONS: Post-ablative Tg concentration is a strong predictor of disease recurrence in WDTC.