Influence of initial treatment on the survival and recurrence in patients with differentiated thyroid microcarcinoma.

Purpose: Differentiated thyroid microcarcinoma (DTM) has a good prognosis and survival, but recurrent disease may appear during follow-up. The aim of this study was to evaluate the influence of initial treatment including surgery and radioactive iodine (131I) on the survival and recurrence in patients with DTM.

Methods: Between January 1979 and December 2006, 130 patients with DTM were retrospectively evaluated, with a median follow-up of 10 years. Total/near-total thyroidectomy was performed in 121 (93.1%) of 130 patients, followed with 131I ablation in 71 (54.6%) of 130 patients.

Results: The probability of disease-specific survival was 97.7% ± 1.3% after 5 and 10 years; the probability of disease-specific survival was 95.9% ± 2.2% after 15, 20, 25, and 28 years after the initial treatment and was significantly influenced by recurrence, clinical stage, and patients' age (P = 0.0001, P = 0.0005, and P = 0.02, respectively). Sex, histopathological type of the tumor, metastases at presentation, initial treatment, performance of radioactive therapy, and risk categories had no influence on survival (P = 0.8, P = 0.6, P = 0.1, P = 0.4, P = 0.5, and P = 0.1, respectively). The overall recurrence rate was 10.8%, (6.9% in lymph nodes, 1.5% in thyroid bed, and 2.3% at distant sites), with a median appearance time of 30 months. Recurrences were significantly influenced by regional metastases at presentation, radioiodine ablation, and initial treatment (P = 0.0002, P = 0.005, and P = 0.003, respectively); there was no relationship based on age, sex, histological type of the tumor, and tumor multifocality.

Conclusions: To perform more accurate surveillance for recurrence, total/near-total thyroidectomy followed by radioiodine ablation may be the optimal initial treatment for patients with DTM.