Metastasis in differentiated carcinomas of the thyroid
Ana Paula Barbosa1, Cláudia Lobo1, João Pedro Teixeira1, Carlos Soares2, João Capela2, Joana Couto1, Raquel Martins1, Ana Paula Santos1, Lima Bastos1, Maria José Bento1, Teresina Amaro1 & Isabel Torres1
Differentiated carcinoma of the thyroid (DCT) of follicular origin is the most frequent endocrine neoplasia and it usually has a good prognosis even in the disseminated disease, due to its slow growing pattern and low dissemination rate. The prevalence of metastasis described in the literature varies between 5 and more than 20%.
Aims: To analyze the clinicalpathological data and their relation with survival of patients (pts) with metastatic DTC.
Material and methods: Retrospective study of clinical, imagiological, cintigraphic, surgical and pathological data of pts with metastatic DTC treated in our institutions between January 1975 and February 2009.
Differences between groups were analyzed with the χ2-test. Survival curve was analyzed with KaplanMeyer method. Results were considered significant for P<0.05.
Results: One hundred and sixteen pts, 88 (75.9%) women (median age 42 years), 28 (24.1%) men (median age 53 years) underwent total 113 (97.4%) and subtotal 3 (2.6%) thyroidectomies followed by radioactive iodine in 115 (99.1%) pts. Pathological study: 54 (46.6%) papillary limited to the thyroid (T1 and T2), 41 (35.3%) papillary with minimal extra-thyroidal extension (T3), 14 (12.1%), follicular, 7 (6.0%) microcarcinoma. Metastatic spread: 43 (37.1%) cervical lymph nodes (N), 25 (21.6%) lung (L), 19 (16.4%) N+L, 5 (4.3%) mediastinal lymph nodes (M), 5 (4.3%) M+L, 5 (4.3%) N+M+L, 3 (2.6%) bone (B), 3 (2.6%) B+L, 2 (1.7%) N+L+B, 1 (0.9%) liver (LV)+B+L, 1 (0.9%) N+B, 1 (0.9%) LV+L, 1 (0.9%) brain+N+L, 1 (0.9%) N+M+LV. Only 1 microcarcinoma had minimal extra-thyroidal extension and N+L metastasis. Bone metastasis were significantly more frequent in follicular than papillary T1 and T2 carcinomas (42.9 vs 7.4%, P<0.001). In the median follow-up time (51 months, minimum 9, maximum 400), 3 patients died, 2 with folicullar and 1 with papillary T3 carcinomas.
Conclusions: Metastatic spread was more frequently observed to the cervical lymph nodes and to the lungs. Bone metastasis were more frequent in the follicular than in the papillary T1 and T2 carcinomas. Despite such metastization, only 3 patients died.