Transanal Endoscopic Microsurgery Versus Endoscopic Submucosal Dissection For Large Rectal Adenomas

Objective: Recent non-randomized studies suggest that extended endoscopic submucosal dissection (ESD) is equally effective in removing large rectal adenomas as transanal endoscopic microsurgery (TEM). If equally effective, ESD might be a more cost-effective approach as this strategy does not require expensive equipment, general anesthesia and hospital admission. Furthermore, ESD appears to be associated with fewer complications. In a randomized trial we will compare the cost-effectiveness and cost-utility of TEM and ESD for the resection of large rectal adenomas. Study design: 15 centers will participate in this multicenter randomized trial comparing TEM versus ESD. Study population: Patients with a large rectal adenoma (≥2cm), located between 2 and 15 cm from the anal verge. Invasive cancer is excluded by histopathology and endoscopic ultrasonography. Patients must be in a health condition that permits general anesthesia. Interventions: Patients will be randomized between a. TEM: under general anesthesia b. ESD under sedation 1. a TEM tube will be inserted in the rectum. With specialized instruments the adenoma will be dissected en bloc by a full thickness excision, after which the patient will be admitted to the hospital. 2. an endoscope will be inserted into the rectum and the submucosa underneath the lesion will be injected with saline to lift the adenoma. With an endoscopic knife (Insulated Tip Knife, Olympus or Water Jet, Erbe) the lesion will be resected through the submucosal plane in an eb-bloc fashion, after which the patient will be observed for at least 24h in-hospital. Primary Endpoint: incidence of recurrence at 12 months Secondary Endpoints: morbidity, subdivided into major (requiring surgery) and minor (requiring endoscopic or medical intervention) anorectal function. disease specific and general quality of life; number of days not spent in hospital from initial treatment until 2 years afterwards; adenoma Sample size: Assuming a comparable baseline recurrence rate for TEM and ESD of 6% and considering an upper limit of 10% for ESD to be non-inferior (beta-error 0.2 and one-sided alpha-error 0.05), 60 patients are needed per group. These numbers provide sufficient power to reveal relevant differences in expected morbidity and in number of days not spent in hospital. Economic evaluation: A cost-effectiveness and cost-utility analysis of ESD against TEM for large rectal adenomas from a societal perspective with respectively the costs per recurrence free patient and the cost per quality adjusted life year as primary outcome measures.

Sex

All

Minimum age

18 Years

Inclusion Criteria:

1. Diagnosed with a large non-pedunculated rectal adenoma (sessile or flat) with a largest diameter of ≥2 cm (estimated by an opened resection snare of 20 or 30 mm).
2. The lower and upper borders of the adenoma are located at ≥2 cm and ≤15 cm from the anal verge, respectively.
3. Biopsies of the lesion did not show malignant neoplastic tissue on histopathological evaluation; only lesions with low or high grade dysplasia are suitable for inclusion.
4. During flexible video endoscopy there are no signs of endoscopic suspicion for submucosal invasive cancer (Kudo pit pattern type V; excavated/depressed type morphology; fold convergence; or large smooth nodule \>1 cm in a flat lesion) (33). In case of doubt, patients will undergo EUS as described at (2).
5. In case doubt remains after flexible video endoscopy, endoscopic ultrasonography (EUS) of the rectal adenoma should exclude invasion into the submucosal layer and exclude pathological lymphadenopathy (lymph nodes \>1 cm). When pathological lymph nodes are present, fine needle aspiration will be performed to exclude lymph node metastasis (N+ disease).
6. If not performed already, total colonoscopy will be done to detect and remove all synchronous colonic adenomas or cancers first. Cecal intubation must be confirmed by identification of the appendiceal orifice and ileocecal valve.
7. The general health condition of the patient permits general anesthesia (ASA- classification I-III).
8. Absence of non-correctable coagulopathy (international normalized ratio \>1,5, or platelet count \<90 × 109/l).
9. Patient age of 18 years or older.

Exclusion Criteria:

1. Preoperative histologically detected malignancy
2. Previous anorectal surgery
3. Contraindications to general anaesthesia

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