Ultrasonography as a method of screening for tracheal invasion by papillary thyroid cancer

To assess the reliability of ultrasonography (US) for detecting tracheal invasion by papillary thyroid cancer (PTC).

We reviewed the clinical and surgical data of 509 patients who underwent surgery for primary PTC during 2003, after routine preoperative US.

Ultrasonography showed possible tracheal invasion in 43 of the 509 patients. However, the US findings could not be evaluated in 32 patients because of high tumor calcification, a tumor diameter greater than 4 cm, or tumor extension inferior to the clavicle. We shaved the tracheal wall in 11 patients and resected the tracheal wall in 2 patients. The sensitivity of US for diagnosing of tracheal invasion was 91%, the specificity 93%, the predictive value of a positive test 25%, the predictive value of a negative test 99%, and the accuracy 93%.

Ultrasonography is a useful method of screening for tracheal invasion. A negative sonogram is a reliable indicator of the absence of tracheal invasion, except when tumors are highly calcified or extend inferior to the clavicle.