Differentiated Thyroid Carcinoma Long-Term Prognostic Factors.

Introduction: Thyroid cancer is the most common cancer in women in Ecuador.

Objective: The aim of this study was to determine the demographics and clinical and treatment variables of patients with papillary or follicular thyroid cancer, referred to as differentiated thyroid cancer (DTC), treated at a third-level hospital in Quito, Ecuador.

Methods: We reviewed retrospectively the medical records of patients with DTC, who underwent surgical treatment, from 1990 to 2019. Data included demographics, pathological information, clinical stage, type of surgery, and radioactive iodine (RAI) adjuvant therapy. Patients were monitored for up to 29 years (median follow-up time 6.9 years).

Results: The corrected overall 5-, 10-, 20-, and 30-year survival rates (Kaplan-Meier) were 93%, 85%, 70%, and 63%, respectively. On univariate analysis, age, histological type, tumor grade, histological variants, capsular invasion, vascular invasion, tumor size, clinical stage, distant metastases at diagnosis, surgical margins, extrathyroidal invasion, radioactive iodine adjuvant treatment, and locoregional recurrence were found to be significant prognostic factors. In a multivariate analysis, the following independent variables: age over 55 years, extrathyroidal spread, metastasis at diagnosis, and stage II to IV raised the risk of death (hazard risk) (HR).

Conclusions: Age over 55 years, extrathyroidal spread, metastasis at diagnosis, and advanced clinical stage were found to have a harmful prognosis and an increased risk of death in a series of Ecuadorian patients surgically treated for a DTC.