Study to Evaluate the Pattern of Nodal Distribution in Papillary Thyroid Cancer.

Abstract

Among the thyroid cancers, papillary thyroid cancer (PTC) is the most common with lymphatic metastasis. It has the propensity to spread to the level II-VI lymph nodes in a predictable manner. We evaluated the pattern of nodal distribution at different levels of neck in papillary thyroid cancer in this Observational Prospective study. Total 41 patients of PTC (Papillary thyroid cancer) were included in the study. 36 out of them were diagnosed as PTC by FNAC and underwent total thyroidectomy and central neck dissection, while 5 patients were histologically confirmed cases of PTC on previous hemithyroidectomy and underwent completion thyroidectomy and central neck dissection .Patients with T3/T4 stage or N1 underwent lateral neck dissection also. Clinicopathological factors such as age, sex, tumor stage, nodal metastasis and extracapsular invasion, were evaluated. Lymph node metastasis was noted in 21 patients (51.2%) and all these patients had central (level VI) lymph node involvement. Among 21 patients, pathological ipsilateral lateral neck metastasis was noted in 6 patients (28.57%) at level II, 10 patients (47.62%) at level III and 8 patients (38.10%) at level IV. Only 5 patients (23.81%) had metastasis at level V. Extracapsular invasion was observed in 10 (24.4%) patients. We concluded that patients with PTC show higher rates of metastasis at central neck (level VI) and are not easily detected on clinical examination or by USG due to low sensitivity but are sensitive and specific for lateral neck nodes in late stages . Thus, ipsilateral selective neck dissection should be considered with total thyroidectomy and central neck dissection in presence of clinically or radiologically evident lateral lymph nodes (preoperatively) and in T3, T4 stage (late stages) tumors.