Hybrid endoscopic mucosal resection and full-thickness resection for large cecal polyp with focal suspicion of submucosal invasive carcinoma

A 72-year-old woman was referred for a possible endoscopic full-thickness resection (eFTR) of a suspected early carcinoma in the cecum without abnormalities on chest/abdomen CT staging. Colonoscopy under propofol sedation revealed a granular laterally spreading tumor (LST-G) with a central slight depression in the surface and an irregular Kudo Vi pit pattern on the cecal floor – well away from the valve of Bauhin and appendix – under propofol sedation (photo 1 and 2). The overall size of the entire lesion was estimated to be at least 25 mm, due to the presence of an unsuspected benign outgrowth behind the fold (photo 3). As a result, the lesion turned out to be too large for a radical ‘en bloc’ eFTR, because the upper limit for a radical resection with eFTR is approximately 20 mm.¹ An endoscopic submucosal dissection (ESD) on the cecal floor was not considered safe, partly in view of the real risk of deeper submucosal invasion. It was therefore decided to perform a combined procedure with the aim of removing the non-suspect part of the polyp by endoscopic mucosal resection (EMR), so that the remaining, suspected invasive part of the lesion can be removed en bloc by eFTR.²

The unsuspected spur lifted easily and could be removed with a cold string in 3 parts and obtained for PA (photo 4 and 5). The size of the remaining part, containing the suspected early carcinoma, was now estimated to be 15-20 mm in size (photo 6). After withdrawing the scope and reintroducing it into the cecum with the eFTR device, the entire remaining lesion could be pulled completely into the cap, after which the over-the-scope clip was fired and the tissue above the clip was reviewed with the integrated string (photo 10). The slide was brought out and pinned for PA assessment (photo 7). A third introduction to the cecum followed to assess the resection plane and clip position (photo 8).

The entire procedure was uncomplicated and the patient was discharged immediately after usual observation. Histopathological examination of the piecemeal EMR section revealed a tubulovillus adenoma with low-grade dysplasia. The eFTR section (over 2 cm) showed an adenocarcinoma extending to mid-submucosa (sm2), with wide free resection margins both basally and laterally (photo 9). There appeared to be no high-risk histological features for lymph node metastases, such as poor differentiation grade, lymphangioinvasion or high grade tumor budding. After multidisciplinary consultation, an additional oncological resection was therefore not performed and further surveillance was chosen.

References:

1. Zwager LW, Bastiaansen B, van der Spek B, et al. Endoscopic full-thickness resection of T1 colorectal cancers: a retrospective analysis from a multicenter Dutch eFTR registry. Endoscopy. 2021.
2. Chua JS, Dang H, Zwager LW, et al. Hybrid endoscopic mucosal resection and full-thickness resection for large colonic polyps harboring a small focus of invasive cancer: a case series. Endosc Int Open. 2021;9(11):E1686-E91.

1: White-light endoscopy (WLE) image of the lesion (LST-G) in the cecum with a central depression. 2: Narrow-band imaging (NBI) with near focus on the suspected, invasive part of the lesion; irregular pit pattern (Kudo Vi). 3: Outgrowth of the lesion appears entirely benign (Kudo IIIl/IV pit pattern and Hiroshima B vascular pattern). 4: Injection of the benign spur; good lifting. 5: Piecemeal endoscopic mucosal resection (pEMR) of the benign spur; looks endoscopically radical.

6: The remaining, suspicious part of the lesion appears suitable for an eFTR. 7: Status after eFTR of the suspected, invasive part; looks macroscopically radical. 8: Result of the eFTR; clip in good position with evident pericolic fat in the resection plane visible (yellow). 9: Histopathological assessment of the tumor with HE staining. 10: Schematic representation eFTR procedure.

Comment Jacques Bergman

Beautiful combination of ‘less-and-more’ in endoscopy. ‘Less’ in the sense of the minimally invasive piecemeal coldsnare resection of the relatively innocent part: safe, fast and without risk of bleeding or perforation. ‘More’ in the sense of the targeted ‘full-thickness’ resection of the carcinoma-suspected part that provided the required maximum vertical margin for removal of this deep submucosal carcinoma. With an ESD this would probably have ended in an R1 resection and/or perforation and the procedure would also have taken 5x as long.

Incidentally, the chance of local lymph node metastasis in such deep submucosal carcinomas without other risk factors is smaller than the mortality of a hemicolectomy, so that this curative combination willn ‘less-and-more’ also fits with ‘less is more’ in endoscopy.

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