[A retrospective cohort study of patients diagnosed of thyroid cancer in the southwest Madrid area. Predictive factors in differentiated thyroid cancer].

OBJECTIVES To analyze the clinical and histopathological features of patients with thyroid cancer in the southwest Madrid area and to identify poor prognostic factors in the subgroup with differentiated thyroid carcinoma (DTC) of the follicular epitelium. PATIENTS AND METHODS A retrospective cohort study of patients diagnosed with thyroid cancer at our hospital from 1998 to 2009. Significant clinical, surgical, and histopathological variables were included in Cox proportional hazard and logistic regression models to identify baseline factors predicting for death, recurrence, and persistent disease in DTC. RESULTS A total of 150 patients with a median age of 49 years and a median follow-up of 5.4 years were enrolled. Histological subtypes were: papillary carcinoma (86%), follicular carcinoma (6.6%), medullary carcinoma (4%), poorly differentiated carcinoma (2.7%), and anaplastic carcinoma (0.7%). At the end of the study, 68% of patients were cured, 3.3% had died (disease-specific mortality, 1.3%), 1.3% were lost to follow-up, 6.7% had persistent biochemical disease, and 2.7% persistent clinical disease, while 18% of patients were pending assessment. The best prognostic model for DTC recurrence was TNM staging (stage II-IV vs. I: HR 5.9, 95% CI 1.3-26.6), while the best model for persistent disease or death was ETA clinical staging (high risk vs. low or very low risk: OR 9.2, 95% CI 2.6-33.2). CONCLUSIONS In our study, disease-specific mortality and persistent clinical disease were low. Classification of DTC patients based on ETA staging after initial treatment was a good predictor of persistent disease or death.