Voice outcome in patients treated with endoscopic laryngopharyngeal surgery for superficial hypopharyngeal cancer

Objectives. Endoscopic laryngopharyngeal surgery (ELPS) is a minimally invasive transoral surgery that was developed to treat superficial larygo-pharyngeal cancer, in which a mucosal lesion is resected transorally while preserving deeper structures by subepithelial injection. The purpose of this retrospective study is to evaluate voice outcome in patients who underwent ELPS for superficial hypopharyngeal cancer. As important structures in producing voice, such as in­trinsic laryngeal muscles, their fascia, and recurrent laryngeal nerve, are located in the medial side of the piriform si­nus and the postcricoid region of the hypopharynx, we focused on patients with cancer lesions involving these re­gions. Methods. From April 2010 to March 2011, 25 consecutive patients with superficial laryngopharyngeal cancer were treated with ELPS at Kyoto University Hospital. Among the 25 patients, 11 patients with cancer lesions on the medial side of the piriform sinus or the postcricoid area were studied. Preoperative and postoperative voice functions including maximum phonation time (MPT), mean flow rate (MFR), jitter, shimmer, soft phonation index (SPI), and noise-to-harmonic ratio (NHR), were compared retrospectively. Results. Five of 11 cancer lesions had submucosal invasion and no lesion had invaded the muscular layer pathologically. T stage was classified as Tis in 5 cases, T1 in 4 cases, and T2 in 2 cases. All lesions involved the medial side of the piri­form sinus and 2 also involved the postcricoid area. Vocal fold movement was normal in all cases after the surgery. Average preoperative and postoperative values for MPT, MFR, jitter, shimmer, SPI, and NHR, were 22.7 seconds and 23.4 seconds, 165 mL/sec and 150 mL/sec, 1.53% and 1.77%, 3.82% and 5.17%, 35.5 and 36.6, and 0.13% and 0.14%, respectively. There was no statistical difference between preoperative and postoperative data for all values ex­amined. Conclusion. ELPS is useful in preserving voice function in the treatment of superficial hypopharyngeal cancer. Preserving the deeper structures including intrinsic muscles and their fascia may be important for preserving voice function as long as the lesions are superficial.