Clinical features of poorly differentiated thyroid papillary carcinoma

Abstract Objective To investigate the clinical feature of the poorly differentiated thyroid papillary carcinoma. Methods We investigate retrospectively 276 thyroid papillary carcinoma patients who underwent initial treatment at our Department who underwent initial treatment at our Department during the 13-year period from 2000 to 2012. We examine the pathological samples of papillary carcinoma retrospectively to investigate the prevalence of a poorly differentiated component in the tumor. Then the disease-specific survival rate, metastasis-free survival rate, and relapse-free survival rate were compared between patients with or without a poorly differentiated component. In addition, well differentiated carcinoma and poorly differentiated carcinoma were compared in relation to the age, sex, TNM stage, and recurrent laryngeal nerve infiltration. Results It was considered appropriate to define tumors with a poorly differentiated component of 10% or more as poorly differentiated carcinoma. There was a significant difference of the T classification but not the N classification between well and poorly differentiated thyroid papillary carcinomas. The disease-specific survival rate, metastasis-free survival rate, and relapse-free survival rate of patients with poorly differentiated carcinoma was significantly lower than that of patients with well differentiated carcinoma, and we considered that this might be due to the higher frequency of local infiltration in patients with poorly differentiated tumors. Conclusion The higher relapse rate compared with well differentiated carcinoma suggests that careful postoperative follow-up of patients with poorly differentiated carcinoma is important, particularly surveillance of distant metastasis.