Bronzwaer MES, et al. - The diagnostic assessment and procedural characteristics of lesions with and without unexpected submucosal invasion were compared. Between unexpected cancers and adenomas, diagnostic assessment of large non-pedunculated rectal polyps showed similar characteristics. During endoscopic mucosal resection (EMR), unexpected cancers were non-lifting in 40%, endoscopically evaluated as incomplete in 33%, and terminated prematurely in 60%. These factors ought to raise suspicion of malignancy in treatment-naïve patients and needed discussion in a multidisciplinary team meeting for deciding on further treatment strategies.