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Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
report a randomized controlled trial (RCT) of the effect of prophylactic clipping of the stalks of pedunculated polyps on hemorrhage risk. Placement of a median of 1.7 clips (placed before transection with snare cautery) on the stalk was effective in preventing overall hemorrhage risk, although this resulted entirely from preventing immediate arterial hemorrhage. There were 2 delayed hemorrhages in the clip and untreated arms each. Thus, placement of hemostatic clips on the stalks of pedunculated polyps was effective in preventing immediate hemorrhage at the time of transection. The authors hospitalized patients with immediate hemorrhage for observation, so clipping reduced hospitalization.
At least several caveats regarding the results deserve discussion. First, there is probably no need to routinely hospitalize patients with arterial hemorrhages that occur during endoscopic resection of colorectal polyps if those hemorrhages are appropriately treated during the procedure.
In the case of pedunculated polyps, this means mechanical closure of the stalk as part of the hemorrhage treatment, which is usually easy to achieve technically because most stalks are easy to access and not wide enough to defy closure. Furthermore, immediate hemorrhage is statistically associated with delayed hemorrhage, but the overwhelming majority of patients with intraprocedural hemorrhage do not experience delayed hemorrhage.
This is at least partly related to the sustained efficacy of the hemostatic treatments used for intraprocedural bleeding and is consistent with the results of the current study.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Second, most expert colonoscopists consider delayed hemorrhage to be more significant than immediate hemorrhage because delayed hemorrhage often requires hospitalization, repeated colonoscopy, and/or transfusion.
Prophylactic clip closure reduced the risk of delayed postpolypectomy hemorrhage: experience in 277 clipped large sessile or flat colorectal lesions and 247 control lesions.
On the other hand, immediate hemorrhage is controlled during the procedure and is usually followed by discharge to home. Because clipping did not result in a difference in delayed hemorrhage in the trial by Gweon et al,
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
the significance of the overall result is diminished. Third, the pedunculated polyps in the study were transected with an initial burst of coagulation current followed by Endocut
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Effects of blended (yellow) vs forced coagulation (blue) currents on adverse events, complete resection, or polyp recurrence after polypectomy in a large randomized trial.
which was performed in nonpedunculated polyps, Endocut delivered by a microprocessor-controlled unit resulted in more immediate bleeding and no difference in delayed bleeding.
Effects of blended (yellow) vs forced coagulation (blue) currents on adverse events, complete resection, or polyp recurrence after polypectomy in a large randomized trial.
Anecdotally, using pure low-power coagulation current for pedunculated polyps, I have not seen an immediate hemorrhage for many years. There is no obvious need to use Endocut in the transection of pedunculated polyps, and it likely contributed to the 10.9% risk of immediate hemorrhage in the control arm.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Further, the pathologic assessment of the resection margin is not affected by the current choice. Fourth, although no adverse events were related to clip placement before snare resection, at least 1 study found that placement of clips on the stalk before transection was associated with an increased risk of thermal injury to the colon wall.
Clips on the stalk could create a zone of resistance to current flow, resulting in thermal injury at the location of the clips when monopolar current is applied to the snare. This may be particularly relevant when clips are positioned at the base of the stalk, as described by Gweon et al.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Clinicians using pretransection application of metal clips should be aware of this risk, even though excess thermal injury was not described in the trial by Gweon et al.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Fifth, most pedunculated polyps are located in the relatively narrow and angulated sigmoid colon, where maneuvers such as counterpositioning a second clip on the cecal side of the stalk, and properly positioning the snare above the clips, can be challenging.
Guideline recommendations regarding prevention of bleeding from pedunculated polyps
Table 1 shows the recommendations of the U.S. Multi-Society Task Force on Colorectal Cancer
for prevention of hemorrhage from pedunculated polyps. Both groups recommend prophylactic stalk treatment when there is a large polyp head or a thick stalk. Whether “prophylactic” means treatment before or after transection of the stalk is not stated in either guideline.
Table 1Recommendations of the U.S. Multi-Society Task Force and the European Society of Gastrointestinal Endoscopy on prevention of bleeding from colorectal pedunculated polyps
Recommending body
Recommendation
U.S. Multi-Society Task Force on Colorectal Cancer
Prophylactic mechanical ligation of the stalk with a detachable loop or clips if head is ≥20 mm or stalk thickness is ≥5 mm
European Society of Gastrointestinal Endoscopy
For head ≥20 mm or stalk ≥10 mm in diameter, pretreatment with dilute adrenaline and/or mechanical hemostasis
Which negative outcome is most important to consider in planning resection of a pedunculated polyp?
Table 2 lists potential negative consequences during or after endoscopic resection of a pedunculated polyp. Bleeding is the adverse event that usually concerns endoscopists, is the primary subject addressed in resection guidelines,
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
that precipitated this editorial. Perforation is rare but anecdotally can occur, presumably from very large lesions pulling the muscularis propria into the stalk. The same mechanism may underlie the occasional postcoagulation syndrome after resection of pedunculated polyps. Clearly, though, perforation and postcoagulation syndrome after resection of pedunculated polyps are rare.
Table 2Adverse outcomes during and after transection of a pedunculated colorectal polyp
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Such lesions are relatively frequent in population screening programs based on the fecal immunochemical test, accounting for >70% of all malignant polyps and one-fourth of T1 cancers.
Occasionally, cancer is endoscopically obvious in pedunculated polyps. Ulceration of the polyp head, often accompanied by disruption of the vascular pattern on the surface of the polyp, reliably predicts cancer (Fig. 1). In those instances, endoscopic resection of a pedunculated polyp is still appropriate, whereas the same features in a nonpedunculated polyp contraindicate endoscopic resection.
Table 3 lists the histologic features of malignant pedunculated polyps that are considered unfavorable and indicate a higher risk of residual cancer in the bowel wall or lymph nodes after endoscopic resection.
British Society of Gastroenterology/Association of Coloproctologists of Great Britain and Ireland guidelines for the management of large non-pedunculated colorectal polyps.
The significance of tumor budding in T1 colorectal carcinoma: the most reliable predictor of lymph node metastasis especially in endoscopically resected T1 colorectal carcinoma.
However, the most relevant risk factor is the positive resection margin. Less than 1 to 2 mm between the cancer and resection margin indicates a possible incomplete resection and residual disease.
In addition, progressive penetration of cancer from the head-neck (Haggitt level 1-2) through the stalk (Haggitt level 3) to the submucosa of the bowel wall (Haggitt level 4), where large blood vessels and high lymphatic vessel density are present, increases the metastatic risk, irrespective of the margin.
This margin between cancer and resection line will be evaluated in every malignant pedunculated polyp. Thus, in a pedunculated lesion that is endoscopically clearly cancer, the rationale for resecting lower on the stalk (farther from the cancer) is intuitively obvious.
Table 3Unfavorable (associated with increased risk of residual cancer in bowel wall or lymph nodes after endoscopic resection) histologic features in a malignant pedunculated polyp
However, the same rationale for low resection on the stalk exists in every large pedunculated polyp, because cancer in pedunculated polyps is hard to predict endoscopically. Experts often advocate endoscopic submucosal dissection (ESD) for nonpedunculated lesions with a significant risk for cancer. ESD through the deeper layers of the gastric submucosa is advocated to optimize pathologic recognition of cancer elements that might be missed by ESD through the superficial submucosa.
Although the use of ESD for every nonpedunculated colorectal lesion with significant cancer risk is impractical, risky, and not currently feasible in the United States,
adjusting our technical approach to large pedunculated lesions to optimize oncologic outcomes is likely much simpler to achieve.
If maximizing the distance between a cancer that may be present in the head of a pedunculated polyp and the resection line is a priority, then prophylactic placement of either clips or loops is potentially a problem (Fig. 2). The presence of a loop or clips forces the endoscopist to place the electrocautery snare closer to the polyp head, compared with where the snare could be positioned if the clips or loop were not present. On the other hand, if the polyp is resected near the base of the stalk, a meticulous assessment of cancer localization and of lymphovascular invasion can be achieved not only close to the head but through the entire stalk. This is especially important in pedunculated polyps with cancer in the stalk (Haggitt level 3), which represent up to one-third of all malignant pedunculated polyps.
Penetration of the cancer generally occurs in a triangular shape, with the triangle base toward the muscularis mucosa and the triangle vertex pointing toward the stalk (Fig. 3). If the resection is too close to the head, 2 negative outcomes could result: (1) a positive resection margin for a polyp that would have been negative if resected closer to the colon wall and (2) increase of the quantitative infiltration at the resection margin because the resection crosses the triangular invasion at its base rather than its vertex. Thus, there could be massive infiltration at the resection margin rather than a few scattered cells had the resection been farther down the stalk (Fig. 3). In this regard, in Japan, diffuse cancer exposed at the resection margin is required to define a positive resection margin.
Although this is not the case in Western countries, a zone of uncertain resection margin can sometimes be prevented by lower resection on the stalk.
Figure 2A, Pedunculated polyp without endoscopic evidence of cancer, but pathologic analysis demonstrated cancer. Yellow arrow, position of detachable snare. Red arrow, stalk becoming ischemic. Green arrow, polyp head. B, Same lesion as in A. Demonstration of detachable snare position forcing resection snare toward the polyp head. Yellow arrow, position of detachable snare. Red arrow, stalk becoming ischemic. Green arrow, polyp head.
Figure 3A, Pedunculated polyp (H&E, orig. mag. ×25) with invasive cancer in the head and stalk. Black dotted line, Haggitt’s line at the interface between neck (level 2) and stalk (level 3) invasion. Green arrowed lines, different potential levels of endoscopic resection through the stalk. The amount of cancer tissue at the resection margin decreases as the resection line moves from Haggitt’s line toward the base of the stalk. (Modified from: Matsuda T, et al. Risk of lymph node metastasis in patients with pedunculated type early invasive colorectal cancer: a retrospective multicenter study. Cancer Sci 2011;102:1693-7; with permission.) B, Histologic section of a malignant pedunculated polyp (H&E, orig. mag. ×1) with a wide resection margin achieved by low transection on the stalk. Yellow lines, potential levels of transection higher up the stalk. The lines closest to the head represent resection through the cancer (positive margin), and the second closest line represents a minimally clear margin.
Although more data are needed to establish an optimal approach with certainty, these considerations make a case for transecting the stalk near the colon wall without preapplication of loops or clips. If forced coagulation current by use of a microprocessor-controlled current is used, the risk of immediate arterial hemorrhage seems extremely low. For best results, including with forced coagulation current, the snare should firmly and circumferentially grip the stalk before current is applied. Good technique includes initial “conditioning” of the stalk by a brief application of coagulation current before mechanical transection begins. A recommendation often made in past decades to leave enough stalk to allow regrasping with the snare in a case of immediate hemorrhage seems no longer necessary with microprocessor-controlled forced coagulation current and good technique. Clips to prevent delayed hemorrhage can be placed after transection.
A disadvantage of this approach is that clips are more expensive than detachable snares. Depending on local resources and priorities, clip closure after low transection of the stalk to optimize oncologic outcomes may not be feasible.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
are to be commended for conducting randomized trials on hemorrhage prevention from pedunculated colorectal polyps. Optimization of all outcomes in the management of malignant polyps requires testing new approaches with new outcomes and endpoints, including reducing adjuvant surgical therapy for malignant pedunculated polyps. Until then, there is a case for snare resection low on the stalk without preapplication of loops or clips, using currents associated with a low risk of immediate hemorrhage, and followed by clip closure of the transected stalk.
Disclosure
Dr Rex is a consultant for Olympus Corporation, Boston Scientific, Aries Pharmaceutical, Braintree Laboratories, Lumendi, Ltd, Norgine, Endokey, GI Supply, and Covidian/Medtronic; the recipient of research support from EndoAid, Olympus Corporation, Medivators, Erbe USA Inc, and Braintree Laboratories; and a shareholder in Satisfai Health. The other authors disclosed no financial relationships.
References
Gweon T.-G.
Lee K.-M.
Lee S.-W.
et al.
Effect of prophylactic clip application for the prevention of postpolypectomy bleeding of large pedunculated colonic polyps: a randomized controlled trial.
Prophylactic clip closure reduced the risk of delayed postpolypectomy hemorrhage: experience in 277 clipped large sessile or flat colorectal lesions and 247 control lesions.
Effects of blended (yellow) vs forced coagulation (blue) currents on adverse events, complete resection, or polyp recurrence after polypectomy in a large randomized trial.
British Society of Gastroenterology/Association of Coloproctologists of Great Britain and Ireland guidelines for the management of large non-pedunculated colorectal polyps.
The significance of tumor budding in T1 colorectal carcinoma: the most reliable predictor of lymph node metastasis especially in endoscopically resected T1 colorectal carcinoma.
Prophylactic application of a hemoclip has been suggested as an alternative to the use of an endoloop for the prevention of postpolypectomy bleeding (PPB) when resecting large, pedunculated colorectal polyps. Therefore, this multicenter, randomized controlled trial investigated the efficacy of prophylactic hemoclip application to reduce PPB during the resection of large pedunculated polyps.
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