The impact of primary tumor volume on local control for oropharyngeal squamous cell carcinoma treated with radiotherapy

Background. A study was needed to determine the effect of primary tumor vol ume on local control of oropharyngeal carcinoma treated with radiation ther apy, with or without induction chemotherapy. Methods. Between July 1983 and April 1995, 114 patients with T2-T4 squamous cell carcinoma of the oropharynx were treated for cure with radiation ther apy, with or without induction chemotherapy, and had a pretreatment CT scan available for retrospective review. All scans were reviewed by a single ra diologist (A. A. M.) to determine the tumor volume of the primary lesion. V olume was measured with a computer digitizer for each CT slice showing the primary lesion. Results. A large variation in tumor volume within a given T stage was found . Multivariate analysis demonstrated T stage to be the most significant fac tor affecting local control. Tumor volume marginally influenced local contr ol (p = .10). Conclusions. Primary tumor volume varies significantly within a given T sta ge and has a marginal impact on the likelihood of local control after radio therapy. (C) 2000 John Wiley & Sons, Inc.