Fig. 2.1
Estimating polyp siz e using biopsy forceps. The biopsy forceps have jaws with 2.5 mm in diameter, which open to a width of 7 mm
For the successful polypectomy, it is also essential to make the optimized endoscopic views. All luminal residues should be removed by water flushing and suctioning, and then the lumen should be adequately distended. The targeted polyp should be located in the 5–6 o’clock position where polypectomy accessories emerge from the scope (Fig. 2.2). It is therefore usually helpful to rotate the scope or occasionally to change the patient’s position. The endoscopist should be familiar with all endoscopic accessories and the diathermy unit. Especially, the power of the diathermy unit is recommended to be checked with regular intervals. The training of the assistant and the communication between the endoscopist and the assistant are also an essential for the safe procedures of polypectomy. Following resection, the endoscopist should carefully check the site to ensure all pathology has been clearly removed and to look for signs of bleeding or perforation. After polypectomy, photographic documentation is again needed (Fig. 2.3).
Fig. 2.2
The targeted polyp was located in the 5–6 o’clock position where polypectomy accessories emerge from the scope during polypectomy
Fig. 2.3
Photographic documentation of tumor base should be recorded after polypectomy
2.3 Indications and Contraindications
It is important to remember that most polyps identified at colonoscopy won’t cause the patient harm immediately. In most cases the adenoma-carcinoma sequence progresses slowly. The endoscopist should therefore always consider the likely natural history of the lesion, the age and comorbidity of the patient and the risks of the intervention, prior to the procedure. However, the malignant potential of individual polyps is never known and even small, diminutive polyps can occasionally develop to cancers. It is therefore advisable that all polyps should be removed unless they are obviously non-neoplastic.
Polypectomy should not be attempted on a lesion that does not lift after submucosal saline injection (Fig. 2.4) [10–12]. Non-pedunculated polyps with overt signs of invasion are also best tattooed and biopsied (Fig. 2.5). Although some specialists are resecting large mucosal lesions or focal non-lifting tumor using endoscopic submucosal dissection techniques, the endoscopist should only consider removing lesions within their level of experience. Polyps found in close to colorectal cancers should be documented rather than removed since polypectomy adds an unnecessary risk if the polyp lies within the resection margins of the tumor. Moreover, some endoscopists suggest that synchronous polyps with proximal colorectal cancers should be removed after appropriate surgical resection of the tumor, because tumor seeding may occur into recent polypectomy sites. Polypectomy should not be undertaken in patients with uncorrected bleeding disorders. Although aspirin and non-steroidal anti-inflammatory drugs do not appear to increase the risk following standard polypectomy, these agents are probably best discontinued for 1 week before planned removal of large or complex lesions. Platelet aggregation inhibitors are felt to pose a particular risk and are also best discontinued 1 week before polypectomy. Good bowel preparation is not only critical for polyp detection but reduces the risk of poor outcome including post-polypectomy syndrome or perforation. Loss of the resected polyp also can be occurred in this situation. Thus, re-scheduling the procedure should be recommended when the endoscopist finds a polyp in the presence of poor bowel preparation .
Fig. 2.4
Positive non-lifting sign
Fig. 2.5
Endoscopic tattooing for tumor localization before surgical resection
2.4 Specific Polypectomy Techniques
2.4.1 Cold Biopsy
A cold biopsy technique is useful for removal of diminutive polyps and avoids the risks associated with thermal injury. The open jaws should be targeted carefully to efficiently remove all abnormal tissue (Fig. 2.6). Large cup biopsies are helpful occasionally. Although this technique is very easy and safe, it has several disadvantages. First, it has a chance to leave residual tissue. Second, it is inefficient when polyp size is over the size of the cup of the forcep jaws. Thirdly, the endoscopic field may become obscured with blood with subsequent biopsies necessitating flushing. The technique is probably best reserved for the smallest of polyps.
Fig. 2.6
Cold biopsy procedure
2.4.2 Hot Biopsy
Hot biopsy is an alternative technique for removing diminutive polyps. It uses both the mechanical force and the electrical burn to remove the abnormal tissue. Because of the risks of transmural thermal injury, it is best avoided in the right colon where the colonic wall is thin. It is now less commonly used than before, because there are a few reports showing that the risk of postpolypectomy bleeding may be increased after hot biopsy. During the procedure, the tip of the polyp is grasped and then tented away from the wall to create a pseudo stalk. Electrocautery is then applied and, since current density concentrates at the narrowest point, the pseudo stalk is cauterized and the tip is then avulsed for histological analysis. The endoscopist should watch carefully during electrocoagulation to avoid the excessive spread of thermal injury to the bowel wall (Fig. 2.7).
