Rationale for elective modified neck dissection.

A retrospective study was conducted to give surgeons direction in deciding which type of modified neck dissection is proper elective treatment for the patient with a clinically negative neck. The medical records of 428 previously untreated patients (seen between January 1, 1970, and December 31, 1979) whose necks (i.e., NO) were electively dissected and who had had a primary squamous carcinoma of the oral cavity, oropharynx, larynx, or hypopharynx were included. The three major types of modified neck dissections studied were the supraomohyoid, the anterior, and the functional. Sixteen percent (70 of 428) of the patients had multiple positive nodes and 6% (28 of 428) had evidence of extracapsular invasion. A unilateral supraomohyoid dissection was most often used for primaries of the oral cavity. Bilateral anterior dissection was common for cancers of the larynx and hypopharynx, and functional neck dissection was equally distributed among the primary sites. None of the patients with primaries of the larynx or hypopharynx had pathologically positive nodes in the submental or submaxillary triangles. Advanced T-stage was generally associated with a greater incidence of subclinically positive nodes. Thirty percent of the patients received postoperative radiotherapy. The total number of nodes removed, the number of positive nodes with or without extracapsular invasion, and the anatomic location of the positive nodes were correlated with the type of dissection, the stage and site of the primary cancer, the use of postoperative radiotherapy, the regional (neck) failure, and survival.(ABSTRACT TRUNCATED AT 250 WORDS)