The Gastroenterology Division is performing endoscopic submucosal dissection (ESD) for en-bloc organ-sparing resection of localized malignant or pre-malignant lesions of the gastrointestinal (GI) tract. Conditions prompting ESD at Penn Medicine include colon, rectal, gastric, and esophageal complex tumors and early cancers, including adenocarcinomas and neuroendocrine tumors.
What is endoscopic submucosal dissection?
A minimally-invasive alternative to open surgery, ESD is a well-established procedure in East Asia. However, given the dearth of training programs, the high degree of technical and surgical proficiency required of practitioners and the need for dedicated instrumentation, ESD is currently available only at advanced surgical centers in the United States.
ESD is distinguished from other endoscopic surgeries by technique and instrumentation. Unique techniques include cautery to mark the boundaries of the target lesion; the application of a viscous solution beneath the lesion to lift it from the GI muscular wall; and precise dissection of the lesion off the underlying muscular layer to resect the lesion en bloc, retrieve the specimen, and close the resection site. In addition to cautery from an advanced electrosurgical generator, a series of dedicated endoscopic electrosurgical knives, traction devices, stitching and closure instruments are unique to the procedure.
Current evidence suggests that ESD offers superior microscopically margin-negative (R0) resections and improved histopathological assessment. Staging of larger lesions and lower recurrence rates have been found superior to endoscopic mucosal resection (EMR). Notably, lesion size is not an impediment to ESD, suggesting an advantage for accurate histological assessment and curative resection.
ESD outcomes have been generally exemplary
A large (692 patients) multicenter prospective assessment of ESD in North American patients with esophageal, gastric, duodenal, and/or rectal lesions demonstrated that ESD can be performed safely and effectively, with a low recurrence rate. The technical resection outcomes achieved in this study offered further support at the time of publication (2021) for ESD as a treatment for select gastrointestinal neoplasms.
Figure 1: Early invasive lesion of the transverse colon.
Further support for these findings was evidenced in a recent retrospective report from Penn Gastroenterology and GI Surgery, which demonstrated an average of 84.5% of patients having ESD experienced R0 resection for large complex benign tumors and early cancers of the esophagus, stomach, colon, and rectum. This rate was comparable to the 84.2% R0 resection rate finding of the multicenter 2021 North American study cited above.
Case Study 1
Mr. F, a 79-year-old gentleman, was referred to Galen Leung, MD, of Penn Gastroenterology following several episodes of rectal bleeding and the finding via colonoscopy of a large, depressed mass in the transverse colon that was concerning for potential cancer. Mr. F’s medical history included treatment for prostate cancer, coronary artery disease (with a prior CABG), and obstructive sleep apnea. Considerations for treatment included Mr. F’s cardiopulmonary disease, making him a less than ideal candidate for a surgical colectomy. Given the potential superficial invasion of the mass, and the lack of other high-risk features, endoscopic submucosal dissection was deemed a curative option for Mr. F, who provided informed consent for the procedure.
Figure 2: ESD resection of lesion from deep layers of the GI tract.
The Procedure: Following preparatory procedures, a second colonoscopy demonstrated a large (3.5 cm by 3.0 cm) sessile, non-granular, lateral spreading polyp with an area of depression in the transverse colon (Figure 1). The polyp occupied ~40% of the colon circumference; on narrow band imaging, there were areas of irregular mucosal pit and vascular pattern, suggesting the potential for early cancer
To clearly identify the boundaries of the lesion in preparation for ESD, the lesion margins were demarcated via high-definition white light imaging and narrow band imaging with thermal marking. A liquid solution with blue dye was then injected beneath the mucosa to lift the lesion from the muscularis propria. A submucosal pocket was then created by a mucosal incision along the anal side of the lesion, which then the lesion was dissected from the underlying deep layers from the anal side to the oral side (Figure 2). Then the right and left sides to the oral side of the pocket were then opened up, and a 4 × 4 cm area was resected.
Figure 3: Dissected polyp specimen
En bloc resection and specimen retrieval were completed (Figure 3), and the resected tissue margins were examined and found clear of polyp tissue. The defect was then closed with endoscopic sutures. No bleeding occurred at the end of the procedure.
Mr. F recovered well from surgery and went home the next morning after a short overnight hospital stay for observation. He will return in six months for follow-up surveillance on the basis of his pathology reports, which revealed a curative resection of an early invasive colon cancer.
Case Study 2
Mr. R was found to have a large, infiltrative, partially obstructive mass in his distal rectum at his most recent colonoscopy. At 66 years old, Mr. R had a history of hypertension and hypothyroidism, and had initially presented to Penn Gastroenterology for a surveillance colonoscopy as the result of a history of colon polyps.
Figure 4: 7.0 cm x 4.0 cm rectal polyp
Because his polyp was concerning for cancer, Mr R was referred to Dr. Leung of Penn Gastroenterology. Following a lower endoscopic ultrasound in which the mass did not appear to be deeply invasive, and in the absence of other high-risk features, Mr. R was deemed to be a good candidate for ESD. The likely alternative surgery would have involved abdominoperineal resection resulting in an ostomy.
The Procedure: Following normal preparatory procedures, a colonoscopy was performed. This found a 7.0 cm x 4.0 cm polyp in the rectum along the left posterior wall, approximately 50% circumferential and approximately 10 cm from the anal verge (Figure 4). The polyp was multi-lobulated, sessile and mixed lateral spreading with large nodular components. On narrow band imaging areas of irregular mucosal pit and vascular pattern were apparent, suggesting the presence of an early rectal cancer.
Figure 5: ESD of large polyp from deep layers of rectal wall.
Preparations were made for the ESD procedure. Demarcation of the lesion was performed with high definition white light and narrow band imaging to clearly identify the lesion boundaries. 35 mL of a liquid solution with blue dye was then injected to provide adequate lift of the lesion from the muscularis propria. Following an incision along the anal side of the lesion into the submucosa to create a submucosal pocket, the lesion was dissected from the underlying deep layers from the anal side to the oral side (Figure 5). Then the right and left sides of the oral side of the pocket were opened. The specimen was then retrieved, achieving an en bloc resection of a 4x8 cm area (Figure 6). The resected tissue margins were examined and clear of polyp tissue.
Mr. R recovered well from surgery and went home the next morning after a brief overnight observation stay. He will return in six months for follow-up surveillance on the basis of his pathology reports, which showed a curative resection of an early rectal cancer.
Figure 6: ESD en bloc resection of a 4x8 cm area of rectal wall.
About Endoscopic Surgery at Penn Gastroenterology and Hepatology
Interventional endoscopic surgery is a staple of the endoscopic faculty at Penn Gastroenterology and Hepatology. Advanced endoscopic procedures include peroral endoscopic myotomy for achalasia (performed since 2014), ERCP with stent placement, therapeutic endoscopic ultrasound, radiofrequency and cryogenic ablative procedures, and endoscopic mucosal resection and submucosal dissection for a variety of conditions, including neuroendocrine tumors and early-stage carcinomas of the gastrointestinal tract.