The purpose of this study is to evaluate the feasibility of a standardized surgical and care process for patients with locally advanced or recurrent rectal cancer that has spread to nearby pelvic organs. When cancer invades adjacent structures (such as the sacrum, bladder, or prostate), a complex procedure called pelvic exenteration (PE) is often required to remove the tumor entirely.

This research does not involve testing new or experimental surgical techniques. All procedures performed in this study are part of standard clinical practice. Instead, the focus of this project is to:

Standardize Procedures: Create consistent, high-quality steps for the surgical team to follow.

Improve Teamwork: Enhance coordination between different medical specialists (such as colorectal surgeons, urologists, and oncologists) to provide better care.

Track Outcomes: Use a patient registry to monitor clinical data and quality of life after surgery through patient-reported surveys.

A total of 24 adult patients will be enrolled over a three-year period. By refining these workflows and monitoring patient recovery, the study aims to ensure that these complex surgeries are performed as safely and effectively as possible.

This prospective, single-center surgical feasibility study is designed to establish and validate standardized protocols for patients undergoing pelvic exenteration (PE), with or without sacrectomy, for locally advanced or recurrent rectal cancer invading adjacent pelvic structures.

The study focuses on three primary operational pillars:

1. Standardization of Surgical Techniques and SOPs The project aims to refine and standardize complex surgical maneuvers to ensure technical consistency across cases. This includes:

   Precise identification and preservation of pelvic nerves.

   Intraoperative assessment of sacrectomy levels (specifically targeting S2-S4).

   Standardization of urological procedures and advanced reconstructive approaches for the pelvic floor.

   Implementation and practical validation of Standard Operating Procedures (SOPs) to achieve consistent R0 resection margins.

2. Prospective Data Integration and Quality of Life Monitoring A systematic case registry will be established to capture comprehensive perioperative clinical data. Beyond clinical metrics, the study integrates Patient-Reported Outcome Measures (PROMs) to evaluate the impact of PE on long-term postoperative function and quality of life. This data will be used to optimize clinical workflows and improve patient counseling regarding functional recovery.

3. Multidisciplinary Team (MDT) Synergy The study reinforces a collaborative care model involving colorectal surgery, urology, orthopedics, oncology, radiology, and pathology. By strengthening MDT collaboration, the project aims to enhance perioperative care quality, from preoperative surgical candidacy review to postoperative management.

As a feasibility study, the enrollment of 24 patients over three years will serve as a pilot to confirm the practicality of these SOPs and the efficiency of the MDT workflow in a high-complexity surgical setting. All procedures fall within the scope of standard clinical practice; the research focus remains on the optimization of care delivery and process standardization.

Inclusion Criteria:

• Adult patients aged ≥20 years.
• Histologically confirmed rectal adenocarcinoma or anal adenocarcinoma.
• Tumor invasion of sacrum (requiring sacrectomy, S2-S4) or anterior structures (e.g., prostate), or lateral structures(SLAM, vessels, nerve) where resection of the invaded organ is necessary to achieve R0 resection, as determined by MDT.
• Surgical candidacy confirmed by multidisciplinary review (colorectal surgery, urology, orthopedics, oncology, radiology, pathology).
• Preoperative imaging (MRI, PET/CT) confirming resectable disease without distant metastasis.
• Signed informed consent obtained.

Exclusion Criteria:

• Unresectable disease or widespread distant metastasis.
• Severe comorbidities rendering major surgery or anesthesia unsafe.
• Patients unable to complete postoperative follow-up or unwilling to participate in PROMs assessment.

Adult patients (age ≥ 20 years) with histologically confirmed locally advanced or recurrent rectal or anal adenocarcinoma invading adjacent pelvic structures (such as the sacrum, prostate, or bladder) who undergo pelvic exenteration (PE) with or without sacrectomy at Chang Gung Memorial Hospital during the three-year study period.

The data that support the findings of this study are available from the corresponding author upon reasonable request