Inclusion Criteria:  o Patients must have given written informed consent  o Subjects with documented gastric or rectal lesions with indication of endoscopic removal by ESD, namely:  Gastric focal lesion with suspicion of early gastric cancer (low or high grade dysplasia with features of early gastric cancer; adenocarcinoma with morphology of superficial lesion and work-up of superficial lesion) Rectal polyps (adenoma or superficial carcinoma) from 0 to 15 cm from the anal margin; with features being recognized indications of ESD: more than 20mm granular LST, more than 20mm non granular LST, more than 20mm villous or bulging polyps, Paris 0-IIa+IIc lesions, lesions with suspicious pattern (Kudo Vi / JNET 2B), lesions with anal canal involvement.  Exclusion Criteria:  Subjects who meet any of the following exclusion criteria cannot be enrolled in the study:  Gastric and rectal neuroendocrine tumour (NET) with indication of ESD will be excluded Gastric and rectal lesions with indication of ESD but strong fibrosis due to previous partial resection will be excluded Subject is currently enrolled in another confounding research Subjects with any other location of ESD (esophagus, duodenum and colon) will not be included.