RADIOLOGIC APPEARANCE OF THE IRRADIATED LARYNX .2. PRIMARY SITE RESPONSE

PURPOSE: To evaluate the computed tomographic (CT) appearance of laryn geal tumors treated with radiation therapy and the ability of CT to de pict persistent or residual tumor. MATERIALS AND METHODS: Sixty-one pa tients with primary squamous cell carcinoma of the larynx or hypophary nx were treated with definitive radiation therapy. CT was performed in all patients before and after treatment. RESULTS: In 32 of 41 patient s with cancer controlled at the primary site, CT showed complete resol ution of tumor, whereas in 10 of 14 patients in whom radiation therapy failed, there was minimal or no reduction in tumor. In a subpopulatio n of patients who underwent repeat imaging, 18 of 19 with turner contr olled at the primary site had complete resolution of tumor. Overall, i n four of 13 patients with 50%-75% reduction in tumor size or persiste nt substantial asymmetry at CT, therapy eventually failed at the prima ry site. CONCLUSION: Lesions that are reduced by 50% or less at 4-mont h follow-up CT are highly suspicious for treatment failure. Repeat CT studies every 4 months is recommended in addition to careful clinical follow-up.