['Wide-field endoscopic mucosal resection (WF-EMR) is an alternative to surgery for treatment of advanced colonic mucosal neoplasia up to 120\u2005mm in size, but has been criticised for its potentially high recurrence rates. We aimed to quantify recurrence at 4\u2005months (early) and 16\u2005months (late) following successful WF-EMR and identify its risk factors and clinical significance.', 'Ongoing multicentre, prospective, intention-to-treat analysis of sessile or laterally spreading colonic lesions ≥20\u2005mm in size referred for WF-EMR to seven academic endoscopy units. Surveillance colonoscopy (SC) was performed 4\u2005months (SC1) and 16\u2005months (SC2) after WF-EMR, with photographic documentation and biopsy of the scar.', '1134 consecutive patients were enrolled when 1000 successful EMRs were achieved, of whom 799 have undergone SC1. 670 were normal. Early recurrent/residual adenoma was present in 128 (16.0%, 95% CI 13.6% to 18.7%). One case was unknown. The recurrent/residual adenoma was diminutive in 71.7% of cases. On multivariable analysis, risk factors were lesion size >40\u2005mm, use of argon plasma coagulation and intraprocedural bleeding. Of 670 with normal SC1, 426 have undergone SC2, with late recurrence present in 17 cases (4.0%, 95% CI 2.4% to 6.2%). Overall, recurrent/residual adenoma was successfully treated endoscopically in 135 of 145 cases (93.1%, 95% CI 88.1% to 96.4%). If the initial EMR was deemed successful and did not contain submucosal invasion requiring surgery, 98.1% (95% CI 96.6% to 99.0%) were adenoma-free and had avoided surgery at 16\u2005months following EMR.'] Is long-term adenoma recurrence following wide-field endoscopic mucosal resection ( WF-EMR ) for advanced colonic mucosal neoplasia infrequent : results and risk factors in 1000 cases from the Australian Colonic EMR ( ACE ) study?