Study: NCT06761287

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Endoscopic resection
Description: Eligible patients will undergo endoscopic submucosal dissection (ESD) after two to six weeks of neoadjuvant treatment completion, depending on the used neo-adjuvant regimen. Procedures will be performed using the GIF EZ-1500 endoscope (Olympus America, Center Valley, PA, USA) and an electrosurgical unit (VIO 300 D; Erbe, Germany) to power the electrosurgical knife (1.5-mm DualKnife J, Olympus America). For mucosal incision, Endocut mode will be used, while Precise or Swift Coagulation modes will support submucosal dissection and hemostasis. An initial submucosal lift created by Glycéol Gel injection. The ERBE Flushing Pump (Erbe, Germany) will supply further submucosal lift during dissection through foot pedal-controlled, pressurized injections of methylene blue and saline solution delivered via the DualKnife J's ceramic-tipped tubing.

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Endoscopic resection
Description: Eligible patients will undergo endoscopic submucosal dissection (ESD) after two to six weeks of neoadjuvant treatment completion, depending on the used neo-adjuvant regimen. Procedures will be performed using the GIF EZ-1500 endoscope (Olympus America, Center Valley, PA, USA) and an electrosurgical unit (VIO 300 D; Erbe, Germany) to power the electrosurgical knife (1.5-mm DualKnife J, Olympus America). For mucosal incision, Endocut mode will be used, while Precise or Swift Coagulation modes will support submucosal dissection and hemostasis. An initial submucosal lift created by Glycéol Gel injection. The ERBE Flushing Pump (Erbe, Germany) will supply further submucosal lift during dissection through foot pedal-controlled, pressurized injections of methylene blue and saline solution delivered via the DualKnife J's ceramic-tipped tubing.

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Endoscopic resection
Description: Eligible patients will undergo endoscopic submucosal dissection (ESD) after two to six weeks of neoadjuvant treatment completion, depending on the used neo-adjuvant regimen. Procedures will be performed using the GIF EZ-1500 endoscope (Olympus America, Center Valley, PA, USA) and an electrosurgical unit (VIO 300 D; Erbe, Germany) to power the electrosurgical knife (1.5-mm DualKnife J, Olympus America). For mucosal incision, Endocut mode will be used, while Precise or Swift Coagulation modes will support submucosal dissection and hemostasis. An initial submucosal lift created by Glycéol Gel injection. The ERBE Flushing Pump (Erbe, Germany) will supply further submucosal lift during dissection through foot pedal-controlled, pressurized injections of methylene blue and saline solution delivered via the DualKnife J's ceramic-tipped tubing.

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Short interval restaging
Description: Close follow-up and endoscopic re-evaluation four to eight weeks after the initial evaluation\* (\*defined as the first evaluation after completion of the neoadjuvant treatment)

Intervention type: BEHAVIORAL
Group type: EXPERIMENTAL
Intervention: Short interval restaging
Description: Close follow-up and endoscopic re-evaluation four to eight weeks after the initial evaluation\* (\*defined as the first evaluation after completion of the neoadjuvant treatment)

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Total mesorectal excision
Description: This technique consists of the surgical complete removal of the rectum, together with the surrounding mesorectum lymphovascular fatty tissue (mesorectum).

Intervention type: PROCEDURE
Group type: EXPERIMENTAL
Intervention: Total mesorectal excision
Description: This technique consists of the surgical complete removal of the rectum, together with the surrounding mesorectum lymphovascular fatty tissue (mesorectum).

Intervention type: PROCEDURE
Group type: ACTIVE_COMPARATOR
Intervention: Total mesorectal excision
Description: This technique consists of the surgical complete removal of the rectum, together with the surrounding mesorectum lymphovascular fatty tissue (mesorectum).