Abstract
Thyroid cancer is a well-differentiated cancer with favorable prognosis among the malignant tumors of the head and neck. However, extension into the mediastinum is observed in rare cases. Although there is a risk of fatal complications associated with the respiratory tract in such cases, increased surgical stress after sternotomy is predicted to cause frequent postoperative complications. Moreover, clear standards for operability have not yet been established. Therefore, in order to obtain findings related to operability and operative procedure, we focused on cases that differed greatly in operability and procedure based on the time when the operations were performed. We conducted a comparative examination of six cases in the 1980s (early cases) and four recent cases (late cases) in which sternotomy was performed at our department. The cases were compared in terms of the following: (1) background factors and extent of spread, (2) operative procedure, (3) postoperative complications, and (4) treatment outcomes. In the early cases, radical mediastinal dissection was performed aggressively for extensive spreading, including undifferentiated cancers (poorly differentiated cancer and squamous cell carcinoma) and papillary cancer; further, the operative procedure was radical. On the other hand, in the late cases, radical mediastinal dissection was performed only for papillary cancer; further, resection of the trachea and esophagus was conservative. Thus, patients in the late cases were discharged without any postoperative complications, and all patients survived. Therefore, it is considered that radical mediastinal dissection by sternotomy should be considered only in cases of mediastinal extension of differentiated thyroid cancer, where only few adjacent organs need to be resected.
