Natural history and clinical outcome of differentiated thyroid carcinoma: a retrospective analysis of 1503 patients treated at a single institution.

ABSTRACT

BACKGROUND: The study evaluates clinical presentation and outcome of differentiated thyroid cancer (DTC) on a large series of patients homogeneously managed. PATIENTS AND METHODS: A cohort of 1503 DTC followed according to a standardized protocol entered the study. Main outcome measures were clinical presentation at the diagnosis, survival, morbidity and prognostic risk factors. RESULTS: Median age at diagnosis was 46 years. Papillary cancer and low pathological tumor-node-metastasis stages represented >80% of cases. Cancer specific survival at 5, 10 and 15 years was 98.6%, 94.7% and 87.4%; 10-year disease-free and progression-free survivals were 96.8% and 17.1%, respectively. Cancer-specific mortality rate was 2.5% [95% confidence interval (CI) 1.7% to 3.4%], recurrence rate was 0.6 % while morbidity rate was 12.6% (95% CI 11% to 14%). Response to radioiodine treatment is the strongest predictor of a good outcome in multivariate analysis (hazard ratio 211, P < 0.0001). Other independent predictor variables are sex, age, histology and distant metastases for survival and metastases for morbidity. CONCLUSIONS: A rigorous initial therapeutic approach leads to a better survival and a very low morbidity. Patients who do not respond to radioiodine treatment have a worse prognosis.