Focal endoscopic intermuscular dissection guided by the pocket-detection method for radical excision of early T2 rectal cancer

An 80-year-old man presenting hematochezia was referred to our institution due to a 20 mm slightly elevated rectal lesion with a central depression (Paris 0–IIa+c) on the right-posterior rectal wall below the inferior Houstonʼs valve ([Video 1]). The macroscopic appearance and virtual chromoendoscopy (JNET III surface and vascular pattern) suggested a deeply invasive cancer ([Fig. 1]). Staging pelvic magnetic resonance imaging revealed rectal cancer with invasion but partial preservation of the muscularis propria (T1b/early T2) without malignant lymph nodes or extramural vascular invasion. A total body computer tomography (CT) scan did not reveal distant metastases. After a multidisciplinary team discussion, the patient refused total mesorectal excision, and an endoscopic local excision was then offered.

Focal endoscopic intermuscular dissection achieving a radical resection of an early T2 rectal cancer.Video 1

Fig. 1 White light appearance (left) of a Paris 0–IIa+c lesion, 20 mm in diameter, located on the right-posterior wall of the distal rectum. Virtual chromoendoscopy (right) was suggestive of deeply invasive cancer (amorphous surface and loose vessel areas, Japan NBI Expert Team [JNET] classification III).

Creating a submucosal pocket towards the deeply invasive component (pocket-detection method [1] [2]), the muscle-retracting sign indicating the deeply invasive area within the lesion was identified ([Fig. 2]) and circumferentially isolated [3]. Following multiband-and-wire pulley traction [4] application, incision of the circular layer of the muscularis propria was performed around the suspected invasive component at a safety distance of 3 mm to achieve R0 while minimising the intermuscular dissection area ([Fig. 3]). The focal endoscopic intermuscular dissection (EID) was completed without complications, and the patient was discharged 24 hours after the resection. Histopathology ([Fig. 4]) revealed a radical resection of a well-differentiated adenocarcinoma invading the muscularis propria without lymphovascular invasion or tumour budding (pT2). Given the radical resection and the patientʼs age and preference, the multidisciplinary team agreed on a follow-up. At the 3-month follow-up, there was no endoscopic recurrence or functional impairment, and the total body CT scan revealed no distant metastases.

Fig. 2 Muscle-retracting sign. Submucosal invasion and fibrosis causing tethering of the muscularis propria to the overlying lesion, narrowing of the submucosal space, and non-staining submucosa. Appearance under saline immersion (left) and CO₂ insufflation (right).

Fig. 3 Appearance of the resection defect following the circumferential incision of the circular layer of the muscularis propria. The submucosal and intermuscular dissection planes are exposed by the multiband-and-wire pulley traction.

Fig. 4 Tissue section (hematoxylin and eosin staining) of the rectal endoscopic resection specimen showing a low-grade adenocarcinoma invading deep into the muscularis propria with margins free of neoplasia. M = mucosa, SM = submucosa, MP = muscularis propria. The dashed line marks the invasive front of the tumour.

The novel focal EID guided by the pocket-detection method enabled safe and R0 resection of a T2 rectal cancer in an elderly patient refusing surgery. Focal EID may decrease the area of circular muscular resection, potentially reducing procedural time and complication rates.

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Conflict of Interest

D. J. T.: Fujifilm, and Olympus research support and consulting. The other authors declare that they have no conflicts of interest.

• References

• 1 Argenziano ME, Sorge A, Poortmans PJ. et al. Knife-assisted full-thickness resection guided by pocket detection method for detection and complete excision of deeply invasive rectal cancer. VideoGIE 2024; 10: 191-193
• 2 Argenziano ME, Sorge A, Hoorens A. et al. Knife-assisted full-thickness resection guided by the pocket-detection method for posterior deeply invasive rectal cancer: A novel endoscopic approach (with video). DEN Open 2025; 5: e70116
• 3 Argenziano ME, Sorge A, Montori M. et al. Diagnostic accuracy of the muscle-retracting sign for determining deep submucosal invasion in early rectal cancer: a prospective observational study. Endoscopy 2025; Epub ahead of print
• 4 Sorge A, Argenziano ME, Poortmans PJ. et al. Band-and-wire pulley traction: endoscopic submucosal dissection of a gigantic gastric polyp aided by a novel adaptive traction technique. Endoscopy 2024; 56: E778-E779

Publikationsverlauf

Artikel online veröffentlicht:
02. Juli 2025