Gastrointestinal cancer is not assessed differently from gastrointestinal mesenchymal tumors and endocrine tumors, etc. For the latter tumors, size is the most critical risk indicator. And as the early stage of tumor, the risk of polyps is related to size, the larger the risk of malignant transformation. For polyps that have undergone malignant transformation, complete endoscopic excision is sufficient if the malignant cells do not penetrate deep into the cushion-like layer below the mucosa. Therefore, it is more important to assess which layer the polyp is located than to measure its size before treatment. In the picture below, the colon tumor is only 1CM in size, which looks like a very common polyp from the colonoscopy, and most of the polyps of this size are not yet cancerous. However, based on our precise preoperative evaluation, this patient could not be resected endoscopically. After laparoscopic surgical resection, pathological examination also confirmed that this small tumor had reached the muscular layer and a lymph node with metastasis was also found in this case. In contrast to my previous short article “Rectal villous adenoma should be treated not only for anal preservation but also for functional preservation”, should the treatment of gastrointestinal tumor be surgical or endoscopic resection? Precise preoperative examination is very important in the planning process. Figure 1: Polyp-like tumor of 1CM size Figure 2: Tumor seen microscopically to have reached the muscular layer Figure 3: Pathology report There are also polyps, albeit large, with obvious roots (tipped polyps) that can be reliably removed by endoscopy. The figure below shows a 4CM polyp with complete removal of the entire polyp including its root by ESD. The mass thus excised allows an accurate case evaluation, is there malignancy? , which layer did the malignant cells enter? Knowing these indicators, a rational treatment plan can be made. If simply given a capsule and then electrocoagulated for excision, the excised mass may be difficult to assess accurately pathologically, creating a dilemma for subsequent management. In this case, the postoperative pathological examination revealed that the polyp had malignant changes, but because the ESD resected specimen was complete, the area and depth of malignant changes could be accurately assessed. After joint analysis by several pathologists, it was determined that the malignant area locally reached the mucosal muscle, but did not break through the mucosal muscle, much less enter the submucosa; there was no vascular or lymphatic vessel invasion. According to the international and domestic standards of colon cancer treatment, additional surgery is not necessary. If the resected specimen under colonoscopy cannot reach the standard of complete resection of ESD, or if the pathological analysis is insufficient, a more radical attitude is needed on the issue of whether to perform additional surgery after polypectomy.