Occult contralateral nodal metastases in supraglottic laryngeal cancer crossing the midline.

We evaluated the risk of occult contralateral neck involvement according to T stage and ipsilateral neck stage in centrally located supraglottic laryngeal cancer. The side largely involved by the tumor was defined as ipsilateral and the other side was defined as contralateral in terms of the neck dissection side. We retrospectively analyzed clinical and pathologic data from a group of 189 centrally located supraglottic cancer patients in which bilateral neck dissection was part of the primary treatment. Among 378 neck dissection specimens, the rate of bilateral metastasis was 33/189 (17.5%). The rate of occult metastases in the contralateral side were 33/75 (44%) and 6/114 (5.3%), when ipsilateral neck was pN+ and pN-, respectively. Clinically or pathologically positive ipsilateral nodes and the extracapsular spread in the ipsilateral positive nodes displayed significantly higher risk of contralateral metastases. The incidence of occult contralateral metastases did not seem to be affected significantly by T stage of the tumor. Our retrospective study confirmed that the probabilistic criteria of the incidence of contralateral occult metastases in supraglottic laryngeal cancer with tumor largely involving one side and crossing the midline. On the basis of our data, there is a high prevalence of contralateral metastases in tumors with clinically or pathologically positive ipsilateral lymph nodes. The extracapsular spread of the nodes is also an important determinant of the contralateral involvement.