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Circumferential endoscopic mucosal resection for Barrett's esophagus: In vitro studies on pigs
"4171
HIGH MAGNIFICATION ENDOSCOPY WITH METHYLENE BLUE C H R O M O E N D O S C O P Y F O R I M P R O V E D DIAGNOSIS OF BARRETT'S ESOPHAGUS AND DYSPLASIA Marcia Irene F. Canto, Tsung-Teh Wu, Anthony N. Kalloo, Johns Hopkins Medical Institutions, Baltimore, MD Methylene blue (MB) selectively stains specialized columnar epithelium (SCE) in Barrett's esophagus (BE). High magnification endoscopy (HME)can provide magnified images of the GI tract but its use with MB staining in BE has not been described. AIM: To study the potential utility of combined MB staining with HME for evaluation of BE. METHODS: A pilot study was prospectively performed with 15 patients with chronic GERD:4 negative controls had no SCE in previous EGD and 11 had BE and biopsy-proven SCE (3 positive controls with long BE, 8 with short BE). 3 BE patients had HGD and 2 had LGD. Detailed assessment of the columnar mucosa was made with standard videoendoscopy (Olympus 1T/2T-100 - mode iI. This was repeated at normal (mode 2) and magnified settings (x 35 - mode 3) using the Olympus GIF-200Z (zoom) videoendoscope. MB staining was then performed and careful inspection repeated at normal and x 35 modes. Biopsies were obtained. The 3 modes of endoscopy were compared with regards to visualization of columnar mucosa and MB staining. MB staining results were correlated with biopsy results. The appearance of dysplastic BE was also characterized. RESULTS:HME showed the velvety, villiform surface of BE in all patients with SCE but not in control patients without SCE in biopsies. It showed the demarcation between BE and gastric mucosa (particularly in short BE), which further improved with selective MB staining of SCE. It led to visualization of small islands missed by modes 1 and 2 in 5 BE patients. It improved visualization of MB staining of SCE. 2/4 control GERD patients were diagnosed with SCE by combined HME and MB-directed biopsy. MB s t a i n i n g highlighted unstained dysplastic SCE within stained nondysplastic SCE. Compared to standard endoscopy, the addition of HME te MB staining improved visualization of the location and appearance of dysplastic BE, which had erythema, mucosal irregularity and thickening, heterogeneity (variation in stain intensity), and/or minute hemorrhage. CONCLUSIONS: Combined MB chromoendoscopy and HME technique may improve diagnosis of dysplastic and nondyplastic SCE by enhancing visualization and increasing biopsy precision. It may aid in the localization and characterization of dysplastic] malignant BE prior to mucosal resection or surgery. It may increase the diagnostic accuracy for SCE in short BE. More research on this technique is warranted. Higher magnification (100x) and correlation with stereomicroscopy may further improve this technique.
"4172
CIRCUMFERENTIAL ENDOSCOPIC MUCOSAL RESECTION F O R BARRETT'S ESOPHAGUS: IN VITRO STUDIES ON PIGS. Thierry Ponchon, Jean-Christophe Saurin, E Herriot Hosp, Lyon France; Jean-Francois Rey, Inst Arnault Tzanck, St Laurent France; Yukio Nakajima, Olympus Co, Hamburg Germany Background: Endoscopic destruction of Barrett s esophagus (BE) by argon plasma coagulation or photodynamic therapy is controversed as remnants of intestinal metaplasia are observed in 30% of control biopsies. On the contrary, endoscopic mucosal resection (EMR) is a well accepted procedure, as treatment can be considered as complete, but it is indicated only for limited esophageal superficial carcinomas. EMR could be theoretically interesting for the circumferential treatment of BE, if its feasibility is proved. We conducted in vitro studies on pigs to assess this feasibility and the safety of the procedure at early stage. Methods: A circumferential resection of the esophagus was attempted in pigs using a large transparent cap (Olympus) attached at the distal end of an videoendoscope. No injection of saline was used prior resection. The videoendoscope was maintained in the middle of the lumen and the wall of the esophagus was aspirated circumferentially in one bloc. Once the rim of tissue seems to be maximal in the cap, snare resection was conducted with cutting current. In 2 pigs, several resections were performed side to side in order to obtain a cylinder of esophagus free of mucosa. Results: The studies were conducted on five 2530 kg pigs. Several EMR were performed on each pigs. All the EMR were circumferential and the maximal height of resection was 3cm. In 2 pigs, a 12 cm long cylinder of esophagus without mucosa was obtained by 5 resec-
VOLUME 53, NO. 5, 2001
tions. Only one bleeding was observed and stopped spontaneously. No perforation was seen. Conclusion: Technically, circumferential resection of esophageal mucosa is easily feasible without perforation. Risk of secondary stenosis has still to be assessed and to be prevented if necessary (resorbable stenting).
"4173
R IS K FACTORS F O R PHOTODYNAMIC T H E RA P Y INDUCED STRICTURES OF THE ESOPHAGUS Mark A. Schattner, Melissa Da Carlson, Allen Ahdoot, Hans Gerdes, Memorial Sloan-Kettering Cancer Ctr, New York, NY Background: Photodynamic therapy (PDT) is an ablative therapy that can be used to treat Barrett's esophagus with high-grade dysplasia (BEHGD)and early esophageal cancers. Stricture formation is a common and significant complication. Strictures may require multiple dilatations before a durable response is obtained. There is no way to predict which patients will develop strictures. Aim: To identify risk factors that will predict who is most likely to develop a stricture following PDT. Methods: All patients who underwent PDT for treatment of BEHGD, high-grade squamous cell dysplasia, or early (T1) esophageal cancers were prospectively followed. All patients were given Photofrin 2mg/kg IV 48 hours prior to light administration. Charts were reviewed and the following factors were identified: age, sex, indication for PDT, number of PDT treatments, dose of light administered, length of diffusing fiber used, length of treated area, overlap in treated area, development of a post PDT stricture, number of dilatations required to maintain long-term dysphagia relief, and outcome. Results: 17 patients were studied. 15 men and 2 women, mean age = 73 years. Indications for PDT: BEHGD in 8 patients, BEHGD after a previous esophagectomy in 2 patients, T1 esophageal cancer in 6 patients, and highgrade squamous cell dysplasia in 1 patient. Median follow up was 8 months. 14 of 17 patients had no residual Barrett's esophagus on follow-up EGD and biopsy. 2 patients had persistent high-grade dysplasia, and 1 patient developed a recurrent malignant nodule. Mild stenosis which required only a single dilatation developed in 2 patients (12%). Strictures developed in 7 patients (41%). These strictures were smooth and had no evidence of malignancy on biopsy (in one patient there was a malignant nodule just proximal to the stricture). The severity of the strictures was determined by the number of dilatations required to maintain long-term dysphagia relief. On average, patients who developed strictures required 8 dilations (range 3-14). Neither age, length of treated segment, total light energy delivered, light energy per cm treated, number of treatments, length of overlapping treatments, nor length of diffusing fiber used were able to accurately predict who would develop a stricture following PDT. Conclusions: None of the factors examined can accurately predict who will develop a stricture after PDT. Future studies should concentrate on other factors such as tissue levels of Photo&in to see if risk factors for stricture development can be identified.
GASTROINTESTINAL ENDOSCOPY
AB159
HIGH MAGNIFICATION ENDOSCOPY WITH METHYLENE BLUE C H R O M O E N D O S C O P Y F O R I M P R O V E D DIAGNOSIS OF BARRETT'S ESOPHAGUS AND DYSPLASIA Marcia Irene F. Canto, Tsung-Teh Wu, Anthony N. Kalloo, Johns Hopkins Medical Institutions, Baltimore, MD Methylene blue (MB) selectively stains specialized columnar epithelium (SCE) in Barrett's esophagus (BE). High magnification endoscopy (HME)can provide magnified images of the GI tract but its use with MB staining in BE has not been described. AIM: To study the potential utility of combined MB staining with HME for evaluation of BE. METHODS: A pilot study was prospectively performed with 15 patients with chronic GERD:4 negative controls had no SCE in previous EGD and 11 had BE and biopsy-proven SCE (3 positive controls with long BE, 8 with short BE). 3 BE patients had HGD and 2 had LGD. Detailed assessment of the columnar mucosa was made with standard videoendoscopy (Olympus 1T/2T-100 - mode iI. This was repeated at normal (mode 2) and magnified settings (x 35 - mode 3) using the Olympus GIF-200Z (zoom) videoendoscope. MB staining was then performed and careful inspection repeated at normal and x 35 modes. Biopsies were obtained. The 3 modes of endoscopy were compared with regards to visualization of columnar mucosa and MB staining. MB staining results were correlated with biopsy results. The appearance of dysplastic BE was also characterized. RESULTS:HME showed the velvety, villiform surface of BE in all patients with SCE but not in control patients without SCE in biopsies. It showed the demarcation between BE and gastric mucosa (particularly in short BE), which further improved with selective MB staining of SCE. It led to visualization of small islands missed by modes 1 and 2 in 5 BE patients. It improved visualization of MB staining of SCE. 2/4 control GERD patients were diagnosed with SCE by combined HME and MB-directed biopsy. MB s t a i n i n g highlighted unstained dysplastic SCE within stained nondysplastic SCE. Compared to standard endoscopy, the addition of HME te MB staining improved visualization of the location and appearance of dysplastic BE, which had erythema, mucosal irregularity and thickening, heterogeneity (variation in stain intensity), and/or minute hemorrhage. CONCLUSIONS: Combined MB chromoendoscopy and HME technique may improve diagnosis of dysplastic and nondyplastic SCE by enhancing visualization and increasing biopsy precision. It may aid in the localization and characterization of dysplastic] malignant BE prior to mucosal resection or surgery. It may increase the diagnostic accuracy for SCE in short BE. More research on this technique is warranted. Higher magnification (100x) and correlation with stereomicroscopy may further improve this technique.
"4172
CIRCUMFERENTIAL ENDOSCOPIC MUCOSAL RESECTION F O R BARRETT'S ESOPHAGUS: IN VITRO STUDIES ON PIGS. Thierry Ponchon, Jean-Christophe Saurin, E Herriot Hosp, Lyon France; Jean-Francois Rey, Inst Arnault Tzanck, St Laurent France; Yukio Nakajima, Olympus Co, Hamburg Germany Background: Endoscopic destruction of Barrett s esophagus (BE) by argon plasma coagulation or photodynamic therapy is controversed as remnants of intestinal metaplasia are observed in 30% of control biopsies. On the contrary, endoscopic mucosal resection (EMR) is a well accepted procedure, as treatment can be considered as complete, but it is indicated only for limited esophageal superficial carcinomas. EMR could be theoretically interesting for the circumferential treatment of BE, if its feasibility is proved. We conducted in vitro studies on pigs to assess this feasibility and the safety of the procedure at early stage. Methods: A circumferential resection of the esophagus was attempted in pigs using a large transparent cap (Olympus) attached at the distal end of an videoendoscope. No injection of saline was used prior resection. The videoendoscope was maintained in the middle of the lumen and the wall of the esophagus was aspirated circumferentially in one bloc. Once the rim of tissue seems to be maximal in the cap, snare resection was conducted with cutting current. In 2 pigs, several resections were performed side to side in order to obtain a cylinder of esophagus free of mucosa. Results: The studies were conducted on five 2530 kg pigs. Several EMR were performed on each pigs. All the EMR were circumferential and the maximal height of resection was 3cm. In 2 pigs, a 12 cm long cylinder of esophagus without mucosa was obtained by 5 resec-
VOLUME 53, NO. 5, 2001
tions. Only one bleeding was observed and stopped spontaneously. No perforation was seen. Conclusion: Technically, circumferential resection of esophageal mucosa is easily feasible without perforation. Risk of secondary stenosis has still to be assessed and to be prevented if necessary (resorbable stenting).
"4173
R IS K FACTORS F O R PHOTODYNAMIC T H E RA P Y INDUCED STRICTURES OF THE ESOPHAGUS Mark A. Schattner, Melissa Da Carlson, Allen Ahdoot, Hans Gerdes, Memorial Sloan-Kettering Cancer Ctr, New York, NY Background: Photodynamic therapy (PDT) is an ablative therapy that can be used to treat Barrett's esophagus with high-grade dysplasia (BEHGD)and early esophageal cancers. Stricture formation is a common and significant complication. Strictures may require multiple dilatations before a durable response is obtained. There is no way to predict which patients will develop strictures. Aim: To identify risk factors that will predict who is most likely to develop a stricture following PDT. Methods: All patients who underwent PDT for treatment of BEHGD, high-grade squamous cell dysplasia, or early (T1) esophageal cancers were prospectively followed. All patients were given Photofrin 2mg/kg IV 48 hours prior to light administration. Charts were reviewed and the following factors were identified: age, sex, indication for PDT, number of PDT treatments, dose of light administered, length of diffusing fiber used, length of treated area, overlap in treated area, development of a post PDT stricture, number of dilatations required to maintain long-term dysphagia relief, and outcome. Results: 17 patients were studied. 15 men and 2 women, mean age = 73 years. Indications for PDT: BEHGD in 8 patients, BEHGD after a previous esophagectomy in 2 patients, T1 esophageal cancer in 6 patients, and highgrade squamous cell dysplasia in 1 patient. Median follow up was 8 months. 14 of 17 patients had no residual Barrett's esophagus on follow-up EGD and biopsy. 2 patients had persistent high-grade dysplasia, and 1 patient developed a recurrent malignant nodule. Mild stenosis which required only a single dilatation developed in 2 patients (12%). Strictures developed in 7 patients (41%). These strictures were smooth and had no evidence of malignancy on biopsy (in one patient there was a malignant nodule just proximal to the stricture). The severity of the strictures was determined by the number of dilatations required to maintain long-term dysphagia relief. On average, patients who developed strictures required 8 dilations (range 3-14). Neither age, length of treated segment, total light energy delivered, light energy per cm treated, number of treatments, length of overlapping treatments, nor length of diffusing fiber used were able to accurately predict who would develop a stricture following PDT. Conclusions: None of the factors examined can accurately predict who will develop a stricture after PDT. Future studies should concentrate on other factors such as tissue levels of Photo&in to see if risk factors for stricture development can be identified.
GASTROINTESTINAL ENDOSCOPY
AB159