Preradiotherapy computed tomography as a predictor of local control in supraglottic carcinoma

Purpose: To determine the utility of pretreatment computed tomography (CT) for predicting primary site control in patients with supraglottic squamous cell carcinoma (SCC) treated with definitive radiotherapy (RT). Materials and Methods: Pretreatment CT studies in 63 patients were reviewed, Minimum length of follow-up was 2 years. Local recurrence and treatment complications resulting in permanent loss of laryngeal function were documented. Tumor volume was calculated using a computer digitiser, and pre-epiglottic space (PES) spread was estimated. The data were analyzed using a combination of Fisher's exact test, logistic regression modeling, and multivariate analyses. Five-year local control rates were calculated using the product-limit method. Results: Local control rates were inversely and roughly linearly related to tumor volume, although there seemed to be a threshold volume at which primary site prognosis diminished. Local control was 89% in tumors less than 6 cm(3) and 52% when volumes were greater than or equal to 6 cm(3) (P = .0012). The likelihood of maintaining laryngeal function also varied with tumor volume: 89% for tumors less than 6 cm(3) and 40% for tumors greater than or equal to 6 cm(3) (P = .00004). Pre-epiglottic space involvement by tumor of greater than or equal to 25% was associated with a reduced chance of raving the larynx (P = .0076), Multivariate analyses revealed that only tumor volume independently altered these end points. Conclusion: Pretreatment CT measurements of tumor volume permits stratification of patients with supraglottic SCC treated with RT alone (which allows preservation of laryngeal function) into groups in which local control is more likely and less likely. pre-epiglottic space spread is not a contraindication to using Ri as the primary treatment for supraglottic SCC. (C) 1999 by American Society of Clinical Oncology.