Radiologic appearance of the irradiated larynx. Part II. Primary site response.
PURPOSE: To evaluate the computed tomographic (CT) appearance of laryngeal tumors treated with radiation therapy and the ability of CT to depict persistent or residual tumor. MATERIALS AND METHODS: Sixty-one patients with primary squamous cell carcinoma of the larynx or hypopharynx were treated with definitive radiation therapy. CT was performed in all patients before and after treatment. RESULTS: In 32 of 41 patients with cancer controlled at the primary site, CT showed complete resolution of tumor, whereas in 10 of 14 patients in whom radiation therapy failed, there was minimal or no reduction in tumor. In a subpopulation of patients who underwent repeat imaging, 18 of 19 with tumor controlled at the primary site had complete resolution of tumor. Overall, in four of 13 patients with 50%-75% reduction in tumor size or persistent substantial asymmetry at CT, therapy eventually failed at the primary site. CONCLUSION: Lesions that are reduced by 50% or less at 4-month follow-up CT are highly suspicious for treatment failure. Repeat CT studies every 4 months is recommended in addition to careful clinical follow-up.