Reply to Yoshida et al.

In the letter from Yoshida et al. entitled ”Successful salvage endoscopic mucosal resection for residual superficial hypopharyngeal carcinoma after chemoradiotherapy, with long-term survival,” the authors report the successful treatment of residual cancer with endoscopic mucosal resection (EMR) after chemoradiotherapy for advanced hypopharyngeal cancer. This report suggests that salvage EMR might be a treatment option for residual or recurrent hypopharyngeal cancer after chemoradiotherapy, although only salvage surgery or chemotherapy have been the treatment options so far. Discussion about the efficacy and safety with an increased number of cases is needed; however, three issues are noted.

First, it is difficult to diagnose the depth of residual cancer. With regard to tumor invasion, it is possible to make a diagnosis by endoscopic ultrasound for residual esophageal cancer, but this is difficult with residual hypopharyngeal cancer and conventional endoscopy is therefore the only available diagnostic technique. However residual cancer cells are not always localized within the epithelium or subepithelial layer in the context of chemoradiotherapy for advanced hypopharyngeal cancer; therefore, cancer cells could remain, with a possibility of local recurrence after EMR. In the report by Yano et al. on salvage EMR for esophageal cancer after chemoradiotherapy [1], local recurrence occurred in 14 % of cases even after complete salvage resection. Based on the skill of the individual endoscopist, the indication of salvage EMR for residual hypopharyngeal cancer is decided by whether the lesion is deemed to be endoscopically resectable. This indication is decided strictly and close follow-up is needed even after complete resection.

Second, innovations to address the problem of fibrosis are necessary. Fibrosis in the radiation field always occurs with CRT. When a solution is injected into the submucosal layer during EMR, it is sometimes difficult to lift the lesion because of fibrosis. Yoshida et al. successfully conducted en bloc resection by EMR, but we have sometimes experienced difficulties because the snare slipped from the lesion, even without a history of radiation. In such cases, the lesion might be resected in fragments or argon plasma coagulation (APC) might be needed because of remaining cancer cells, and this could make precise histological evaluation difficult. In order to overcome these difficulties, endoscopic submucosal dissection (ESD) should be used [2]. We have experience of ESD for hypopharyngeal cancer that was developed for the radiation field, and dissection from the fibrotic submucosal layer was possible; however, this should be conducted by a very experienced ESD endoscopist and should not be carried out without careful consideration.

Third, cooperation is necessary between endoscopists and otolaryngologists. Yoshida et al. pointed out that therapy for residual hypopharyngeal carcinoma after chemoradiotherapy is usually decided by only otolaryngologists. If endoscopic resection is accepted widely as a salvage treatment option, discussion of the therapeutic strategy between endoscopists and otolaryngologists is necessary. At our institute, the therapeutic plan for hypopharyngeal cancer is discussed and ESD is conducted with the cooperation of otolaryngologists. In the future it will become increasingly important to decide the therapeutic plan and to treat hypopharyngeal cancer in cooperation with otolaryngologists.

Competing interests: None

References

• 1 Yano T, Muto M, Hattori S. et al . Long-term results of salvage endoscopic mucosal resection in patients with local failure after definitive chemoradiotherapy for esophageal squamous cell carcinoma.  Endoscopy. 2008;  40 717-721
• 2 Iizuka T, Kikuchi D, Hoteya S. et al . Endoscopic submucosal dissection for treatment of mesopharyngeal and hypopharyngeal carcinomas.  Endoscopy. 2009;  41 113-117