[Extrathyroidal thyroid cancer : results of tracheal shaving and tracheal resection]

Extrathyroidal thyroid cancer invading the laryngotracheal system (UICC stage pT4a) represents a progressive process of infiltration of the tracheal wall layers from the outer to the inner parts of the trachea. These tumors usually present with high proliferation activity correlating with a reduced long-term prognosis. In contrast to intraluminal manifestation requiring complete wall resection, in cases of non-transmural invasion, complete tumor removal can be sometimes achieved by extraluminal tangential resection (shaving). Tangential resections, however, are associated with a higher frequency of microscopically invaded resection margins (R1 resection rate >40%). The available comparative studies (all retrospective, maximum EBM level 3) analyzing oncological outcome show inconsistent results. In more recently published studies, however, complete wall resection in well-differentiated thyroid cancer with tracheal invasion only was found to be associated with longer recurrence-free and tumor-specific survival when compared to shaving. Deep larynx invasion is associated with reduced long-term prognosis when compared to invasion of the trachea. Salvage resections should therefore be performed in selected cases only.