The relation of CT-determined tumor parameters and local and regional outcome of tonsillar cancer after definitive radiation treatment

Purpose: To investigate the value of CT-derived tumor parameters as predict or of local and regional outcome of tonsillar squamous cell carcinoma treat ed by definitive radiation therapy. Methods and Materials: The pretreatment CT studies of 112 patients with ton sillar squamous cell carcinoma were reviewed. After redigitizing the films, primary and nodal tumor volume was calculated with the summation-of-areas technique. The nodal CT aspect was graded using a 3-point scale (homogenous , inhomogeneous, and necrotic), Mean follow-up time was 33 months. Actuaria l statistical analysis of local and regional outcome was done for each of t he covariates; multivariate analysis was performed using Cox's proportional hazards model. Results: In the actuarial analysis, CT-determined primary tumor volume was significantly correlated with local recurrence rate (p < 0.05) when all pat ients were considered, but primary tumor volume did not predict local contr ol within the T2, T3, and T4 category. CT-determined nodal volume was signi ficantly related to regional outcome (p < 0.01), but nodal density was not. Total tumor volume was not significantly related to locoregional outcome ( p = 0.1). In the multivariate analysis, the T and N categories were the ind ependent predictors of local and regional outcomes, respectively. Conclusion: Compared to other head-and-neck sites, primary and nodal tumor volume have only marginal predictive value regarding local and regional out come after radiation therapy in tonsillar cancer, (C) 2001 Elsevier Science Inc.