Advances in endoscopic equipment and increased interest among endoscopists have led to higher detection rates of superficial pharyngeal cancer, with a concomitant rise in endoscopic treatments. Since early-stage treatment has been shown to improve overall survival, the current focus has shifted toward achieving safer therapeutic procedures. With recent improvements in image quality, ultrathin endoscopes are increasingly being utilized for therapeutic purposes. Based on our experience using ultrathin endoscopes for superficial pharyngeal cancer, we evaluated the efficacy and safety of this approach.

We retrospectively analyzed 75 patients with 123 lesions who underwent endoscopic submucosal dissection (ESD) using an ultrathin endoscope for superficial pharyngeal cancer at our institution between June 2021 and October 2025. The control group consisted of 64 patients with 85 lesions treated with ESD using a standard-diameter endoscope during the same period. The ultrathin endoscope used was the GIF-1200N (Olympus), while the control group was treated using the GIF-260J or GIF-290T (Olympus). With the ultrathin endoscope, ESD was performed without the use of hemostatic forceps or a waterjet function. After tumor resection, the endoscope was exchanged for a standard one, and hemostatic forceps were used for hemostasis. Procedure time, en bloc resection rate, R0 resection rate, local injection volume, lesion size, resected specimen size, and postoperative complications were retrospectively compared between the two groups.

In the ultrathin and control groups, the mean age was 73 and 70 years, respectively; the proportion of male patients was 92% vs 89%; and the proportion with a history of prior esophageal cancer treatment was 85.3% vs 87.5%. Lesions were located in the hypopharynx (91 vs 53) and oropharynx (32 vs 32). The procedure time was 33.4 vs 32.8 minutes, lesion size was 15.7 vs 18.5 mm, and resected specimen size was 28.8 vs 29.6 mm. The en bloc resection rate was 99.2% vs 100%, while the R0 resection rate was 83.7% vs 77.6%. The local injection volume was significantly lower in the ultrathin group (3.2 vs 6.4 mL). Postoperative complications included pneumonia and hemorrhage (pneumonia 4 cases and hemorrhage 1 case vs pneumonia 2 cases), all of which resolved with conservative management. Significant differences were observed in lesion size and local injection volume. In seven cases (6%), the procedure was converted from an ultrathin to a standard endoscope due to difficulty in maintaining adequate visualization.

Although this study has limitations, including potential selection bias, ESD using an ultrathin endoscope demonstrated therapeutic efficacy and safety comparable to those of standard endoscopes. A key advantage of the ultrathin endoscope is its ability to allow early entry into the submucosal layer, facilitating dissection. However, in 6% of cases, conversion to a standard endoscope was necessary due to impaired visualization, highlighting the need for further technical improvements.