2019 年 112 巻 5 号 p. 277-284
Recently, with the advances in diagnostic endoscopy techniques, the rate of diagnosis of early-stage hypopharyngeal cancer has been increasing. Treatment outcomes have also improved because of advances in the techniques of transoral mucosal resection. We investigated the treatment outcomes of 60 cases of locally confined early hypopharyngeal cancer who were treated by TLM at our institution. The overall 5-year cause-specific survival of the patients was 88%; the rates for patients with stage I, II, III and IV disease were 95%, 92%, 60% and 54%, respectively. However, there were no patients with primary death. The 5-year local control rates in patients with T1, T2 and T3 disease were 93%, 89% and 50%, respectively. The 5-year laryngeal preservation rate in patients with T1, T2 and T3 disease were 96%, 93% and 75%, respectively.
The efficacy of neoadjuvant chemotherapy (NAC) followed by TLM was investigated in 8 patients, including 1 patient with T1 disease, 3 patients with T2 disease, and 4 patients with T3 disease. None of the patients, except for one patient with T3 disease, had local recurrence. There is a possibility that the indication for NAC can be extended to patients with locally advanced hypopharyngeal cancer potentially suitable for TLM.
Some importance of the histoanatomical characteristics of the hypopharynx was recognized. Microscopic magnification images at the supraglottic level have revealed two kinds of elevator muscles of the pharynx in the posterolateral hypopharyngeal wall, whereas the stylopharyngeus and palatopharyngeus run longitudinally inside the inferior constrictor muscle. The stylopharyngeus and palatopharyngeus are clearly delineated by fasciae. The anterolateral hypopharyngeal wall between the superior horn and the lamina of the thyroid cartilage has no muscle layer. The superior laryngeal artery and vein and internal branch of the superior laryngeal nerve pass between these structures en route to the larynx. The pharyngeal branch of the vagus nerve and a branch of the superior thyroid artery are seen outside of the inferior constrictor in the posterolateral hypopharyngeal wall. A precise understanding of the histoanatomical characteristics of the hypopharynx is expected to be helpful for successful performance of TLM by surgeons, with decreased morbidity rates and improved rates of laryngeal preservation, by preventing unnecessary tissue damage.