Endoscopic resection of colonic polyps - A review

Abstract

Endoscopic polypectomy has become standard care for the
treatment of colonic polyps. While about 90% of polyps are
small in size and easy to resect, a small percentage of polyps
are of large size (>2 cm) and broad base and endoscopic resection
is a real challenge for the endoscopist. An appropriate
technique for safe removal of these large colorectal polyps
has been developed and includes submucosal injection
of large amounts of normal saline with diluted epinephrine
and piecemeal resection. We address the importance of adding
a few drops of methylene blue in the submucosally injected
fluid to enhance the margins of the lesion and increase
the accuracy of resection. The success rate of polypectomy of
large polyps is more than 90%, while up to 10% of patients
may finally require surgical treatment due to malignancy
or incomplete resection. Small pieces of the polyp that remain
unresected at the margins during polypectomy can be
destroyed by argon plasma coagulator. Immediate bleeding
after polypectomy can usually be successfully treated with
diluted epinephrine injection and placement of hemoclips or
loops, while delayed bleeding is rare (1%). Perforation of the
bowel using this technique is very rare (0.3%). In addition,
all modern and new techniques for the resection of colorectal
polyps are described. Colonoscopic polypectomy is considered
among the high-risk procedures to induce significant
bleeding, so, prior to polypectomy, adjustment in anticoagulation
is necessary. For patients with high-risk conditions for
a thromboembolic event, warfarin therapy should be discontinued
3 to 5 days before the procedure. The decision to administer
heparin once INR falls below the therapeutic levels
should be individualized For elective high-risk procedures,
temporary discontinuation of newer antiplatelet medications
(such as clopidogrel), particularly if the patient is on concomitant
aspirin, is desirable, preferably for 7-10 days. In the absence
of a pre-existing bleeding disorder, endoscopic procedures
including polypectomy may be performed in patients
taking aspirin and other NSAIDS in standard doses Antibiotic
prophylaxis in patients undergoing polypectomy should
be limited to patients with a prosthetic valve, history of endocarditis,
presence of systemic-pulmonary shunt or a synthetic
vascular graft less than 1 year old.