Endoscopic Submucosal Dissection (ESD): The Organ-Sparing Revolution in Early Gastrointestinal Cancer Treatment
Endoscopic submucosal dissection (ESD) enables complete en bloc removal of early GI cancers without surgery, achieving 100% five-year disease-specific survival for curatively resected lesions. Hong Kong, home to the world-renowned CUHK Institute of Digestive Disease, is a global leader in this transformative technique.
Introduction
Gastrointestinal (GI) cancers remain among the leading causes of cancer-related mortality worldwide. Colorectal cancer ranks as the third most common cancer globally, while gastric cancer and oesophageal cancer continue to pose significant health challenges, particularly in the Asia-Pacific region. Early detection through screening programmes has dramatically improved survival rates, but the true revolution in GI cancer management lies in the development of advanced endoscopic techniques that can treat early-stage cancers without the need for major surgery.
Endoscopic submucosal dissection (ESD) represents the pinnacle of therapeutic endoscopy — a minimally invasive technique that enables the complete removal of precancerous and early cancerous lesions from the gastrointestinal tract in a single piece (en bloc resection). This organ-sparing approach preserves the patient's natural anatomy, avoids the risks and recovery burden of open or laparoscopic surgery, and delivers oncological outcomes that rival those of surgical resection.
Understanding ESD: A Precision Technique
Endoscopic submucosal dissection is a highly specialised procedure that requires advanced training and considerable technical expertise. Unlike conventional polypectomy or endoscopic mucosal resection (EMR), which are limited to smaller lesions and often result in piecemeal removal, ESD allows the complete en bloc resection of lesions regardless of their size.
The procedure follows a systematic approach:
Lesion Assessment: Using high-definition endoscopy with magnification and chromoendoscopy (dye-spraying techniques), the endoscopist carefully evaluates the lesion's size, morphology, and depth of invasion. Advanced imaging technologies such as narrow-band imaging (NBI) and blue laser imaging (BLI) enhance the visualisation of surface patterns and vascular architecture, enabling accurate prediction of histological grade before any tissue is removed.
Circumferential Marking: Small electrocautery marks are placed around the lesion's perimeter, typically 3–5 mm outside the visible margin, to define the resection boundary and ensure complete removal with adequate safety margins.
Submucosal Injection: A specialised solution (often containing hyaluronic acid or glycerol) is injected into the submucosal layer beneath the lesion. This creates a fluid cushion that lifts the lesion away from the underlying muscle layer, providing a safe dissection plane and reducing the risk of perforation.
Circumferential Incision: Using specialised electrosurgical knives (such as the IT knife, Dual knife, or FlushKnife), the endoscopist makes a precise incision through the mucosa along the marked boundary, completely encircling the lesion.
Submucosal Dissection: The endoscopist carefully dissects through the submucosal layer beneath the lesion, separating it from the muscle wall. This is the most technically demanding phase, requiring meticulous control to maintain the correct dissection plane while avoiding injury to the muscle layer.
Specimen Retrieval and Wound Management: The resected specimen is retrieved for detailed histopathological examination. The mucosal defect is inspected for any bleeding or muscle injury, and haemostatic clips or coagulation may be applied as needed.
Clinical Outcomes: What the Evidence Shows
The clinical evidence supporting ESD has matured considerably over the past decade. Long-term follow-up studies have demonstrated outstanding oncological outcomes:
A landmark study examining long-term outcomes of colorectal ESD reported a five-year disease-specific survival rate of 100% for patients with curatively resected lesions. None of the patients in the curative resection group died of colorectal cancer during the follow-up period, confirming that ESD achieves outcomes equivalent to surgical resection for appropriately selected early cancers.
The en bloc resection rate for ESD consistently exceeds 90% across major centres, compared with approximately 50–70% for EMR when treating larger lesions. This higher rate of complete, single-piece removal translates directly into lower local recurrence rates — typically less than 2% for ESD compared with 10–20% for piecemeal EMR.
| Outcome Measure | ESD | Conventional EMR | Surgical Resection |
|---|---|---|---|
| En bloc resection rate | >90% | 50–70% (large lesions) | 100% |
| Local recurrence rate | <2% | 10–20% | <1% |
| 5-year disease-specific survival | ~100% (curative) | Variable | ~100% |
| Hospital stay | 2–4 days | 1–2 days | 5–10 days |
| Return to normal activities | 1–2 weeks | 3–5 days | 4–8 weeks |
| Organ preservation | Yes | Yes | No (partial/total resection) |
| Perforation risk | 2–5% | <1% | N/A (surgical) |
Hong Kong's Excellence in Therapeutic Endoscopy
Hong Kong has established itself as a global leader in advanced endoscopic techniques, with the Chinese University of Hong Kong's Institute of Digestive Disease (IDD) serving as a world-renowned centre for training, research, and clinical excellence in therapeutic endoscopy. The IDD's research has revolutionised the management of gastrointestinal diseases and reshaped clinical practice guidelines internationally.
Hong Kong's endoscopists have been at the forefront of developing and refining ESD techniques for both upper and lower GI tract lesions. The city's gastroenterology centres are equipped with the latest generation of high-definition endoscopes, advanced imaging systems, and specialised ESD instruments. This combination of technical expertise and cutting-edge technology enables Hong Kong's specialists to tackle complex lesions that might be deemed unsuitable for endoscopic treatment elsewhere.
For GCC patients, Hong Kong's gastroenterology services offer several compelling advantages. The high volume of ESD procedures performed ensures that endoscopists maintain peak proficiency. The integration of artificial intelligence-assisted polyp detection during screening colonoscopy enhances the detection of subtle lesions that might otherwise be missed. Furthermore, the availability of comprehensive pathology services ensures rapid and accurate histological assessment of resected specimens.
Who Is a Candidate for ESD?
ESD is primarily indicated for early-stage gastrointestinal neoplasms — lesions confined to the mucosal or superficial submucosal layer — where the risk of lymph node metastasis is negligible. Common indications include early gastric cancer meeting expanded criteria, colorectal laterally spreading tumours and large sessile polyps, early oesophageal squamous cell carcinoma, Barrett's oesophagus with high-grade dysplasia, and duodenal adenomas.
The decision to proceed with ESD versus surgical resection is made through careful multidisciplinary assessment, considering the lesion's size, location, morphology, predicted depth of invasion, and the patient's overall health status. Advanced endoscopic imaging plays a crucial role in this decision-making process, enabling accurate preoperative staging without the need for invasive biopsies.
Recovery After ESD
One of the most significant advantages of ESD over surgical resection is the dramatically shorter recovery period. Most patients can resume a soft diet within 24 hours of the procedure and are discharged from hospital within two to four days. Normal activities can typically be resumed within one to two weeks, compared with four to eight weeks following surgical resection.
Patients are advised to follow a modified diet for approximately two weeks after the procedure and to avoid strenuous physical activity during this period. Follow-up endoscopy is typically scheduled at three to six months to confirm complete healing and to assess for any residual or recurrent lesion. Long-term surveillance follows established guidelines based on the histopathological findings of the resected specimen.
The Future of Therapeutic Endoscopy
The field of therapeutic endoscopy continues to evolve rapidly. Emerging technologies include robotic-assisted endoscopic platforms that may enhance precision and reduce operator fatigue during complex procedures, artificial intelligence systems that can provide real-time guidance during ESD by identifying tissue planes and predicting perforation risk, and novel submucosal injection agents that maintain longer-lasting tissue elevation.
These innovations, combined with the growing evidence base supporting ESD's oncological equivalence to surgery for early GI cancers, suggest that the role of therapeutic endoscopy will continue to expand in the coming years.
Conclusion
Endoscopic submucosal dissection has established itself as a transformative technique in the management of early gastrointestinal cancers and precancerous lesions. Its ability to achieve complete en bloc resection while preserving the patient's organ integrity represents a fundamental advance in cancer care. Hong Kong's position as a global centre of excellence in therapeutic endoscopy, combined with its world-class research institutions and experienced gastroenterologists, makes it an outstanding destination for patients seeking the most advanced endoscopic treatments available.
