Metastasis of Differentiated Thyroid Carcinoma: A Descriptive Study of 75 Patients

Abstract

Introduction: Differentiated Thyroid Carcinoma (DTC) is the most common endocrine malignancy, and is generally of favorable prognosis. However, this latter is significantly worse when initial distant metastasis is present. The aim of our study is to describe the clinical, paraclinical, and therapeutic aspects of metastatic carcinomas in patients followed-up at the Endocrinology Department of the CHU Ibn Rochd in Casablanca, Morocco. Methods: This is a retrospective descriptive study of patients diagnosed with metastatic differentiated thyroid cancers and followed in the endocrinology service at the university hospital of Ibn Rochd in Casablanca over a 34 years period (1986- 2020). The variables studied were age, histological type and features, TNM stage, and metastasis localizations. Data analysis was performed using SPSS 22.0 software. Results: We included 75 patients in our study. The mean age at diagnosis was 46.4 years ± 14.2 years. The sex ratio M / F: 0.1. Metastases were revelatory of DTC in 19 cases. Fifty-seven patients had lymph node metastasis, 17 patients had bone metastasis and 15 patients had lung metastasis. The most frequent histological types were classical papillary carcinoma (47%), papillary carcinoma with vesicular differentiation (21%), then vesicular carcinoma (11%). Regarding the histological characteristics, capsular effraction was found in 35% of cases, vascular emboli in 18% and multifocality in 23% of cases. Analysis of the variables studied showed that gender was not a predictive factor for the appearance of a certain type of metastasis. However, patients older than 55 were significantly more likely to develop lung metastases (p=0.01). Concerning histological features, the existence of vascular emboli was significantly associated with the apparition of lymph node and bone metastases (p=0.01) as well as lung metastases, although not significantly (p=0.1). The mortality rate in our sample was relatively low at 8%. Conclusion: Patients with vascular emboli were more likely to develop lymph nodes and bone metastases, and patients older than 55 were more likely to develop lung metastases. Even if metastases occur, prognosis is generally favorable for DTCs compared to other types of thyroid cancers.