Computed tomography reliably evaluates hypopharyngeal squamous cell carcinomas (SCC) regarding the infiltration of specific anatomic structures and tumor volumes, both of which have been shown to be predictors of local control in patients treated with radiation therapy alone. However, an association of specific infiltrated structures and/or tumor volume with local control has not been investigated for surgical treatment; thus, we determined relationships of various infiltrated anatomic structures and tumor volume with local control in patients with hypopharyngeal SCC treated with primary surgery. In 45 hypopharyngeal SCC, tumor volumes were measured by pretreatment CT, and extent of tumor infiltration was determined by postoperative pathologic examination. All patients had clinical follow-up for recurrent tumor at the primary site. Statistical analysis basically consisted of chi-square and U-tests. Local control rate was 84.4% (38 of 45). Tumor volume was significantly associated with local control (p=0.004). Six of 16 (38%) patients with tumor volumes > or =8.1 cm3 (mean) had a local recurrence, which is significantly (p=0.003) more compared with 1 of 29 (3%) in the group of patients with volumes <8.1 cm3. Among all evaluated anatomic structures, only a tendency for significant association with local control was found for tumor involvement of the tonsils and the extralaryngeal soft tissues. The determination of tumor volumes by CT helps predict local control in patients with hypopharyngeal SCC treated with primary surgery.