Background and objective: Identifying the characteristics of regional extension and accurately evaluating the extent of regional invasion is the key to delineate the target volume of hypopharyngeal carcinoma. This study was to investigate the characteristics of regional invasion of hypopharyngeal carcinoma using the enhanced computed tomography (CT) scan.
Methods: CT images of 65 patients with hypopharyngeal carcinoma treated at Sun Yat-sen University Cancer Center between August 2000 and September 2008 were retrospectively analyzed. The patients included 58 males and two females, with a median age of 55 years.
Results: Pyriform sinus carcinoma (50 cases)easily extended to aryepiglottic fold (98%), posterior hypopharyngeal wall (80%) and ipsilateral epiglottis (82%), preepiglottic space (66%), arytenoid cartilage (74%), paraglotic space (82%), ventricular bands (72%), vocal (62%), laminae of thyroid cartilage (58%) and lateral wall of oropharynx (52%). Posterior pharyngeal carcinoma (14 cases) usually invaded pyriform sinus (100%), aryepiglottic fold (92.9%), postcricoid region (71.4%), prevertebral fascia (71.4%) and esophagus (64.3%). One case of postcricoid carcinoma spread to pyriform sinus, posterior wall of hypopharynx, aryepiglottic fold, aryepiglottic cartilage, paraglotic space, cricoid cartilage thyroid cartilage and esophagus.
Conclusion: Regional invasion of hypopharyngeal carcinoma is mainly direct extension through tissues. Tissues close to the primary tumor site and lack of regional tissue barrier are easier to be encroached and destroyed. The skip lesion is not detected. Routine prophylactic irradiation of nasopharynx and base of skull is not necessary.