Introduction
The majority of patients with thyroid carcinoma have well-differentiated
disease limited to the thyroid gland. However, 6–13% of these tumors
can present with extra-thyroid extension (ETE). [1, 2] ETE has been
well-recognized as a poor prognostic indicator, with 10-year overall
survival (OS) rates dropping by more than 50% compared to tumors
without ETE [3].
Tracheal invasion is a specific form of ETE and it is often recognized
only at the time of surgery.[4] Surgical techniques for treating
tracheal invasion range from shaving the trachea to various forms of
tracheal resection. Tracheal shaving is commonly performed for tumors
with minimal invasion of the perichondrium, and it consists of sharp
removal of all gross disease from the surface of the trachea while
leaving the mucosa intact.[4, 5] Shave excision harbors a high risk
of microscopic residual disease,[6-8] A number of studies reported
similar survival and local control rates for shave resections and more
aggressive procedures in carefully selected patients.[9-11] That
finding, however, has been called into question by the demonstration of
a worse survival and a higher recurrence rate in shave resections,
despite adjuvant radioactive iodine (RAI) and external beam
radiotherapy.[12, 13]
The aim of this study was to compare outcomes of minimal tracheal
invasion to other forms of ETE, and to analyze outcomes according to the
eighth edition of the American Joint Committee on Cancer (AJCC) staging
manual.