A depressed lesion (Type 0-IIc), 9 mm in diameter in the descending colon 1. (a) Ordinary white-light view. (b) After indigo carmine spraying. (c) En face view after indigo carmine spraying. It seemed that the surface of the lesion is rather well preserved except for a tiny defect at the center which had been caused by a biopsy by the previous doctor. (d) During the injection. (e, f) After the injection is completed. (g) Push the tip of the snare against the normal mucosa proximal to the lesion, and open it. (h) Put the snare around the lesion. (i) Close the snare and turn on the electric current. (j) The specimen was unrolled and spread using tweezers and pinned on a small disk of cork. (k) Low-power microscopic view of the resected specimen. (l) The lesion was minimally invasive [1]
The retrieved specimen(s) should not directly go to a container with formalin. The specimen should be unrolled and spread using tweezers and pinned on a small disk of rubber or cork before being fixed with formalin. Otherwise the pathological evaluation concerning the invasion depth or cut margins would be extremely difficult and unreliable.
It is better to dip the pinned specimen it to formalin as soon as possible. A few drops of scopolamine butyl bromide onto the rear side of the specimen may help relax the muscularis mucosae and unroll and spread the specimen.
In order to make a precise pathological diagnosis of invasion depth and cut margin, it is important to prepare tissue slices of the most suspicious parts. For that purpose it is better that the endoscopist himself cut the spacemen with a razor, viewing the stereomicroscopic images of the specimen.
8.6 Prevention and Management of Complications
8.6.1 Hemorrhage
Bleeding can be divided into intra-procedural and post-procedural, and the latter can be further divided into immediate and delayed. The rate of bleeding after colorectal EMRs is reported to be 1.15–1.7% [2]. The bleeding rate is higher in the rectum and the cecum, mainly because there are often large LSTs. The bleeding rate is higher in intramucosal cancers than in adenomas and higher in invasive cancers than in intramucosal cancers probably due to the higher vascularity.
In case of bleeding, hemoclips or coagulating forceps are used for hemostasis. A closure of the mucosal defect with clips may prevent delayed bleeding in high-risk cases.
8.6.2 Perforation
The rate of perforation associated with colorectal EMR/piecemeal EMR is reported to be 0.58–0.8% [2], which is definitely lower than in ESD. Perforation is divided into immediate and delayed; the former is caused by the involvement of the muscle layer during the resection, and the latter is caused by the excessive diathermy during the resection. The perforation rate is higher in larger lesions. It is higher in intramucosal cancers than in adenomas and higher in invasive cancers. In case of an invasive cancer, perforation might result in dissemination of cancer cells as well.
An immediate perforation should be closed with clips. If it is not successful, an emergency surgery is necessary. In case of a delayed perforation, re-intubation of colonoscope and clip closure of the perforated site would be difficult, and therefore a surgical operation is usually required.
8.6.3 Remnant/Local Recurrence
After EMR/piecemeal EMR for a lesion suspected to be invasive, the mucosal defect should be carefully observed not to overlook any remnant. Image enhancement especially with magnification is useful for detecting a remnant. A residual lesion should be immediately treated with a snare or argon plasma coagulation.
The resected specimen should be evaluated pathologically to confirm a curative resection. When the resection is not curative, additional surgery should be considered. In case of piecemeal EMR, pathological evaluation can be inaccurate. Therefore follow-up colonoscopy to look for a local recurrence should be performed earlier than in case of en bloc resection. Generally speaking, the larger the number of pieces, the higher the recurrence rate.
8.7 Conclusion
A lesion suspected to be only slightly invasive (T1a cancer) can be treated endoscopically but better be resected en bloc. An utmost attention should be paid during an EMR for T1(SM) carcinoma in order to prevent complications or recurrence.
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