Page 70 - Read Online

Page 2 of 11 Suwa et al. Mini-invasive Surg 2022;6:20 https://dx.doi.org/10.20517/2574-1225.2021.123

Keywords: Superficial nonampullary duodenal epithelial tumors, SNADETs, duodenal tumors, cold snare
polypectomy, CSP, underwater EMR, UEMR

INTRODUCTION
The opportunities for the diagnosis and treatment of superficial nonampullary duodenal epithelial tumors
(SNADETs) have been increasing, and the treatment strategy for small lesions has become a matter of
concern. In the esophagus, stomach, and colon, endoscopic submucosal dissection (ESD) has been
established as a relatively safe procedure that achieves a higher en bloc resection rate with negative margins
compared to endoscopic mucosal resection (EMR), which reduces the local recurrence rate. However, the
duodenum has the following anatomical disadvantages: it has a very thin muscular layer; there is poor
operability of the endoscope; the duodenum is a retroperitoneal organ that is close to the pancreas; and
there can be perioperative exposure to the bile and pancreatic juice, which causes a high incidence of
[1]
complications during endoscopic resection. A previous report showed that duodenal ESD has high
complication rates, such as intraoperative perforation (12%), delayed perforation (4%), and delayed bleeding
(4.5%). Therefore, an alternative method to ESD is desired, and that should be a reliable resection method to
prevent residual recurrence as well as minimal perioperative complications. Recently, cold snare
polypectomy (CSP) and underwater endoscopic mucosal resection (UEMR) have been introduced as
minimally invasive treatments and are becoming more widely accepted.

We reviewed the outcomes of CSP and UEMR for SNADETs, including the results in our institution.

COLD SNARE POLYPECTOMY
[2]
In 1992, CSP was first reported by Tappero et al. as “cold snare excision” for colorectal tumors; currently,
its use is wide spread for the treatment of small lesions in the colon. CSP is a simple and safe endoscopic
procedure that removes the lesions by mechanical strangulation of both the lesion and the normal
surrounding mucosa, by using only a snare, without the use of submucosal injection or electrocautery.

CSP for colorectal polyps
CSP for colorectal polyps has already been established as one of the standard treatment options, and
multiple reports have shown good treatment outcomes. Kawamura et al. reported the outcomes of CSP
[3]
compared with hot snare polypectomy (HSP) for the treatment of 796 sessile adenomatous colorectal polyps
that were 4-9 mm in size in a multicenter randomized controlled trial (RCT). The complete resection rates
for CSP and HSP were 98.2% and 97.4%, respectively, and they were proven to be non-inferior (P < 0.0001).
Moreover, even in the larger subgroup of colon polyps that were 6-9 mm, the complete resection rate was
100%, suggesting that CSP could be indicated for lesions less than 10 mm in size.

A further advantage of CSP compared to HSP is a lower delayed bleeding rate. Even in the patients who
underwent prophylactic clipping, comprising 81% (325/402) of the patients who had HSP and 9% (38/402)
of the patients who had CSP, the delayed bleeding rate was 1.9% (4/209) for the HSP patients and 0% for the
CSP patients, and the differences were significant (P = 0.02) .
[4]
For lesions larger than 10 mm, Murakami et al. compared CSP for lesions < 10 mm versus CSP for lesions
[5]
≥ 10 mm and reported that the < 10 mm group had a significantly higher en bloc resection rate (100% vs.
93.2%, P < 0.001) and a higher histopathological complete resection rate than the ≥ 10 mm group (72.7% vs.
54.0%, P = 0.001).