2 The procedure
2.1.1 Gastric lesions include benign, dysplastic, and malignant tumours. Patients may be asymptomatic or experience loss of appetite and weight, anaemia and abdominal discomfort or pain.
2.1.2 Current treatment options for small gastric lesions are snare polypectomy (for protruding lesions) or endoscopic mucosal resection (EMR) (for 'flat' lesions). EMR usually removes lesions piecemeal; in contrast, ESD aims to remove lesions intact and with a margin of healthy tissue.
2.2.1 Endoscopic submucosal dissection aims to remove lesions without the need for open abdominal surgery. It is usually preceded by diagnostic endoscopy, biopsy and imaging investigations.
2.2.2 The procedure is carried out with the patient under sedation or general anaesthesia. Using endoscopic visualisation, the submucosa is injected with saline to help lift the lesion. This fluid may contain a pigment to help define the lesion, and adrenaline to reduce bleeding. A circumferential mucosal incision is made with an electrocautery knife around the lesion. Submucosal dissection is then carried out, parallel to the muscle layer, aiming to remove the lesion intact and with a healthy margin of tissue. A transparent hood may be used to retract the already dissected part of the lesion out of the visual field. Haemostasis is achieved by electrocautery. Endoscopic clips may be used for larger vessels or to manage perforation.
Sections 2.3 and 2.4 describe efficacy and safety outcomes from the published literature that the Committee considered as part of the evidence about this procedure. For more detailed information on the evidence, see the overview.
2.3.1 A non-randomised comparative study of 900 malignant lesions (patient numbers not stated) reported significantly greater complete resection rates of 95% (544/572) for ESD vs 64% (210/328) for EMR, and curative (with tumour-free margins) resection rates of 83% (473/572) vs 59% (195/328) respectively; p < 0.05 for both comparisons.
2.3.2 A non-randomised comparative study of 896 patients (1020 malignant lesions) reported significantly greater complete en-bloc resection rates for non-ulcerated lesions of 93% (157/169) for ESD compared with 43% (343/790) for EMR, and histologically clear margin resection rates of 93% (157/169) vs 25% (194/790) respectively (p < 0.01).
2.3.3 A case series of 59 premalignant or malignant lesions (patient numbers not stated) reported en-bloc resection by ESD in 86% (44/51) and free-margin complete resection in 73% (37/51) of lesions.
2.3.4 The non-randomised comparative study of 900 lesions reported no recurrence among ESD-treated lesions and recurrence in 4% (13/328) of EMR-treated lesions (p < 0.05).
2.3.5 The non-randomised comparative study of 896 patients reported no recurrence in ESD-treated patients at a mean 19.4-month follow-up, and recurrence rates of 3% (10/347) in ESD-treated patients and 4% (21/478) in EMR-treated patients during 83.2-month follow-up.
2.3.6 The case series of 59 lesions reported local recurrence in 5 patients treated by piecemeal ESD at up to 8-month follow-up.
2.3.7 The Specialist Advisers listed key efficacy outcomes as en-bloc and curative resection rates, recurrence rate and survival.
2.4.1 Two non-randomised studies – 1 of 900 lesions and the other of 346 patients – reported perforation in 4% (20/572) and 5% (11/243) of ESD-treated lesions or patients, and 2% (5/328) and 2% (2/103) of EMR-treated lesions or patients respectively (differences reported as not significant). In the study of 346 patients, 3 perforations in ESD-treated patients and 1 in an EMR-treated patient were detected intraprocedurally but the others were recognised post-procedurally (timing not stated). All perforations following ESD were managed non-surgically with a combination of endoscopic clipping, fasting, nasogastric tube drainage and antibiotics.
2.4.2 A non-randomised study of 655 patients (714 lesions) reported that perforations were significantly more frequent in ESD-treated patients than in EMR-treated patients (4% [11/303] vs 1% [5/411] of lesions) (p < 0.05). All patients were managed endoscopically (not otherwise described).
2.4.3 The Specialist Advisers listed bleeding as an anecdotal adverse event and considered the theoretical risk of perforation leading to tumour seeding.