Fatores preditores de metástase cervical e padrão de disseminação regional nas formas clássica e folicular do carcinoma papilífero da tireoide

Abstract

INTRODUCTION The papillary thyroid carcinoma (PTC) is the most malignant tumor incidence in this gland and results in high cervical lymphatic spread. One of the main characteristics of this tumor is the cervical lymphatic dissemination, which the diagnosis depends on the propaedeutic method used. In clinical exams up to 30% of metastasis are diagnosed, an incidence that can reach 80% in cases submitted to elective neck dissection. It is a consensus that patients with evident cervical metastasis (N+) should be submitted to therapeutic neck dissection, although the extension of this procedure is still discussed. In patients with a clinically negative neck (N0), the elective neck dissection prescription is a controversial subject. PURPOSE 1. To evaluate the incidence and predictor factors of cervical metastasis. 2. To compare the characteristics (size and number) of metastatic lymph nodes to those free of metastasis. 3. To study the dissemination pattern of cervical metastasis in PTC. METHOD A retrospective study involving 101 patients with PTC submitted to total thyroidectomy associated with neck dissection. The patients were distributed in two groups according to the presence (N+) or absence (N-) of cervical metastatic lymph nodes. Clinical and anatomopathological factors were evaluated, analyzing the cervical dissemination pattern and dissected lymph node characteristics according to these factors. RESULTS The incidence of cervical metastasis in PTC was 50.5%. Besides the metastasis in the central neck compartment, 18.8% of patients presented concomitant metastasis in the lateral compartment. All metastasis were ipsilateral to the primary tumor, both in the central and lateral compartments. There was no statistically significant difference in the size of lymph nodes among groups with and without cervical metastasis (p = 0.34). Group N+ presented a greater number of dissected lymph nodes related to group N-, comparing only the central neck compartment (p = 0.01). The univariate analysis demonstrated that age below 45 years, primary tumors greater or equal to 1,0 centimeter, multi centered, with extrathyroidal extension and angiolymphatic invasion were predictive factors for metastasis (p < 0.05). Gender and follicular variant had no impact on the cervical lymphatic dissemination. Multivariate analysis showed that patients with multifocal tumors and angiolymphatic had an increased risk of cervical lymphatic spread (p = 0.014, OR = 4.113 and p = 0.003, OR = 5.997). Tumors greater than or equal to 1.0 cm had a greater risk of cervical lymphatic spread (p = 0.043, OR = 3.098). In this analysis, it was not possible to quantify the risk of metastasis for patients that tumors have extrathyroidal extension and age less than 45 years (p> .05). Of the 101 patients, 2 (1.9%) developed hypoparathyroidism permanently. Of the 202 exposed nerves, no cases of inadvertent injury were detected. CONCLUSIONS Cervical metastases were always ipsilateral in relation to the primary tumor. Age below 45 years, tumors greater or equal to 1,0 centimeter, multi centered, extrathyroidal extension and angiolymphatic invasion are determinant factors for cervical lymphatic dissemination. Although N+ patients presented a higher amount of lymph nodes in the central compartment, the size of the lymph nodes was not a determinant factor for neck metastasis.