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

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.

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.

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.

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.