Design and evaluation of a subclassification system for supraglottic laryngeal cancer.

The management of supraglottic laryngeal cancer is predicted upon tumor staging as determined by the American Joint Committee Classification (AJCC). Because of changes in both radiotherapy and surgical treatment, the current AJCC may lack the detail and specificity required for accurate selection of treatment. An expanded classification system should provide predictive information that would aid in clinical decision making. Using the AJCC as a foundation, a subclassification system based upon existing knowledge of laryngeal anatomy, embryology and pattern of tumor spread was developed. This system identifies those cancers that involve subsites deemed to represent regions of increased risk for spread. The validity of this subclassification system and its clinical application was assessed by reviewing 139 cases of supraglottic laryngeal cancer and performing a statistical analysis with respect to treatment outcome. The results of this study support the conclusion that two subpopulations of laryngeal tumors, those with a subsite designation of infrahyoid epiglottis, and those demonstrating fixation of the vocal cord, may benefit from a more aggressive treatment protocol.