Optimizing Patient Selection for Surgery Using Pathologic Analysis Following Neoadjuvant Therapy in Locally Advanced Rectal Cancer

Feasibility of the endoscopic resection technique in the context of locally advanced rectal cancer treated with neoadjuvant therapy including radio-chemotherapy. This will be assessed by the curative, en-bloc, and R0 resection rates.

This will be assessed by the rate of local or distant recurrences and the need of salvage surgery within 1, 3 and 5 years following the neoadjuvant treatment and endoscopic resection.

This is defined as the absence of residual visible tissue after endoscopic resection

This is defined as a single piece endoscopic resection, with clear margins

This will be defined as any complication occuring during the performance of the endoscopic procedure, such as muscle galling, rectal muscle perforation, minor or major bleeding, anesthesia-related adverse events, endoscopic material defect

This will be assessed by evaluating the incidence of procedure-related adverse events (AEs) and serious adverse events (SAEs) within 30 days post-procedure. This includes bleeding rates, perforation rates, infection rates among other complications.

This will be assessed by evaluating the incidence of late procedure-related complications within 1, 3 and 5 years after the procedure. This includes delayed haemorrhage, delayed perforation, stenosis, stricture, infection and local pain among other complications

This will be assessed by the correlation between endoscopic tumor characteristics and the rates of recurrence and salvage surgery. Endoscopic tumor characteristics include the presence of a non-lifting sign, muscle retraction sign, fibrosis, and the description of vessels density (low/moderate/high)

This will be assessed by the correlation between residual tumor characteristics (e.g. resected specimen surface, the presence of residual tumor, tumor differentiation, margin status, lymphovascular invasion (LVI), perineural invasion (PNI), fibrosis degree, tumor budding) and the rates of recurrence and salvage surgery

This will be assessed by the correlation between the degree of pathological response (e.g., complete, partial, or poor response) and the rates of recurrence and salvage surgery

This will be assessed by evaluating molecular biomarkers such as Next Generation Sequencing (NGS) on the resected specimen, and correlating these findings with the rates of recurrence and salvage surgery

Overall survival (OS) and disease-free survival (DFS) at 1, 3 and 5 years.

The average time taken to perform the endoscopic resection, measured in minutes and reported by the endoscopist

Number of days patients are hospitalized post-procedure