Although endoscopic submucosal dissection (ESD) has been applied for superficial pharyngeal cancer, no prospective trials have been reported. To investigate the efficacy and safety of ESD for superficial pharyngeal cancer, we conducted a prospective phase II trial.

Fifty-four patients with 73 lesions were enrolled from September 2010 to August 2014, and ESD was performed. The primary endpoint was the complete resection rate. Secondary endpoints were safety, recurrence-free survival, overall survival, and incidence of metachronous pharyngeal cancer.

Fifty-four patients had stage 0-III cancer: stage 0, n = 22; stage I, n = 14; stage II, n = 17; and stage III, n = 1. The en bloc resection rate was 100%, and the complete resection rate was 79.5% (58/73 lesions; 95% confidence interval, 68%-88%). No serious adverse events related to ESD were encountered. Four patients required nasogastric intubation and feeding. No patients required percutaneous endoscopic gastrostomy and tracheotomy. Swallowing, speech, and airway functions were preserved in all patients. One of the 54 patients died of an unrelated illness. Median follow-up was 27 months (range 6-55 months). Local cervical lymph node metastasis was observed in 1 patient, and the case was salvaged successfully with lymph node dissection. The 3-year overall and recurrence-free survival rates were 97.7% and 98.1%, respectively. Cumulative development of multiple cancers of the pharynx at 3 years was 18.4%.

ESD appears to be a safe and effective minimally invasive treatment in patients with superficial pharyngeal cancer. (Clinical trial registration number: UMIN000003623.)