AP-NOSES: A Prospective Multicentre Registry of Natural Orifice Specimen Extraction in Minimally Invasive Colorectal Surgery (AP-NOSES)

May 22, 2026 updated by: Isaac Seow En, Singapore General Hospital

AP-NOSES: A Prospective, Multicentre Registry of Natural Orifice Specimen Extraction in Minimally Invasive Colorectal Surgery Across the Asia-Pacific Region

Natural orifice specimen extraction (NOSE) is a minimally invasive colorectal surgical technique in which the surgical specimen is removed through a natural orifice, including transanal or transvaginal routes, thereby avoiding an abdominal extraction incision. Observational studies suggest that NOSE may reduce wound-related morbidity and improve postoperative recovery, but prospective multicenter data evaluating long-term outcomes remain limited.

AP-NOSES is a prospective, multicenter observational registry evaluating clinical, patient-reported, and long-term wound outcomes following minimally invasive colorectal surgery with NOSE or transabdominal specimen extraction. The primary objective is to compare time to incisional hernia within 24 months between NOSE-eligible patients undergoing planned NOSE extraction and NOSE-eligible patients undergoing planned transabdominal extraction.

Secondary objectives include evaluation of postoperative complications, extraction-related morbidity, bowel function, urinary and sexual function, oncologic outcomes, and long-term patient-reported and clinical outcomes across participating centers.

This study does not alter routine clinical care. Surgical technique, perioperative management, and follow-up are performed according to local institutional practice.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

Natural orifice specimen extraction (NOSE) is an established minimally invasive colorectal surgical technique that enables removal of the surgical specimen through transanal or transvaginal routes while avoiding an abdominal specimen extraction incision. Existing retrospective studies and meta-analyses suggest that NOSE may reduce postoperative pain, wound morbidity, and length of hospital stay without compromising oncologic outcomes. However, prospective multicenter data evaluating long-term abdominal wall outcomes and patient-reported outcomes remain limited.

Incisional hernia is a common long-term complication following colorectal surgery and is closely associated with the abdominal extraction site. By avoiding an abdominal extraction incision, NOSE may reduce extraction-site morbidity and long-term incisional hernia risk. AP-NOSES was designed to prospectively evaluate these outcomes in a multicenter setting using predefined eligibility criteria and a concurrent comparator cohort.

AP-NOSES is a prospective observational multicenter registry coordinated by Singapore General Hospital. Consecutive adult patients undergoing elective minimally invasive colorectal resection with planned intact specimen extraction are eligible for enrollment. Participating centers include tertiary colorectal units within the Asia-Pacific region.

The primary comparative analysis is conducted within a predefined NOSE-eligible cohort. Exposure groups are defined according to planned specimen extraction strategy:

  1. Planned NOSE extraction (transanal or transvaginal), and
  2. Planned transabdominal extraction among patients meeting protocol NOSE eligibility criteria.

Planned and achieved extraction routes, reasons for non-performance of NOSE, operative details, postoperative complications, and oncologic outcomes are prospectively recorded.

The primary outcome is time to incisional hernia within 24 months following index colorectal surgery.

Secondary outcomes include postoperative complications, extraction-site morbidity, surgical site infection, readmission, reoperation, pathologic outcomes, patient-reported quality-of-life and functional outcomes, bowel function, urinary and sexual function in selected patients, and oncologic outcomes including recurrence and disease-free survival.

Patient-reported outcomes are assessed using validated instruments including EQ-5D-5L, Body Image Scale (BIS), Low Anterior Resection Syndrome (LARS) score, International Prostate Symptom Score (IPSS), International Index of Erectile Function-5 (IIEF-5), and Female Sexual Function Index-6 (FSFI-6), where applicable.

This study is observational and does not mandate changes to standard surgical or postoperative management. Data are entered into a secure centralized REDCap database using coded study identifiers.

Study Type

Observational

Enrollment (Estimated)

800

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Sampling Method

Non-Probability Sample

Study Population

Adult patients undergoing elective minimally invasive colorectal resection with planned intact specimen extraction at participating tertiary colorectal centers in the Asia-Pacific region.

Description

Inclusion Criteria:

  • Age 21 years or older
  • Elective minimally invasive colorectal resection (laparoscopic or robotic intent)
  • Planned intact specimen extraction
  • Eligible for natural orifice specimen extraction (NOSE) or transabdominal specimen extraction according to study protocol
  • Ability to provide informed consent

Exclusion Criteria:

  • Emergency colorectal surgery
  • Planned transanal total mesorectal excision (TaTME)
  • Planned ultralow anterior resection with planned anastomosis 3 cm or less from the anal verge
  • Planned abdominoperineal resection (APR)
  • Planned permanent end stoma without restoration of intestinal continuity
  • Planned multivisceral resection
  • Generalized peritonitis or uncontrolled intra-abdominal sepsis
  • Pregnancy
  • Pre-existing ventral or incisional hernia at the planned extraction site
  • Planned specimen extraction through a prior laparotomy incision containing mesh
  • Fixed distal obstruction, severe pelvic stenosis, or other anatomical constraint precluding intact specimen extraction

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

Cohorts and Interventions

Group / Cohort
Intervention / Treatment
Planned NOSE Extraction
Patients undergoing planned natural orifice specimen extraction (NOSE), including transanal or transvaginal extraction, during elective minimally invasive colorectal surgery.
Procedure: Natural Orifice Specimen Extraction
Specimen extraction through a natural orifice, including transanal or transvaginal extraction, during minimally invasive colorectal surgery.
Planned Transabdominal Extraction
NOSE-eligible patients undergoing planned transabdominal specimen extraction during elective minimally invasive colorectal surgery.
Procedure: Transabdominal Specimen Extraction
Specimen extraction through an abdominal incision during minimally invasive colorectal surgery.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Time to Incisional Hernia Within 24 Months
Time Frame: 24 months after index surgery
Time from index colorectal surgery to first clinical or radiologic diagnosis of incisional hernia at or adjacent to the specimen extraction site.
24 months after index surgery

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Overall Postoperative Complications
Time Frame: 30 days after surgery
Postoperative complications within 30 days classified according to the Clavien-Dindo grading system.
30 days after surgery
Surgical Site Infection
Time Frame: 30 days after surgery
Incidence of postoperative surgical site infection following minimally invasive colorectal surgery.
30 days after surgery
Extraction-Site Complications
Time Frame: 30 days after surgery
Extraction-related morbidity including specimen rupture, contamination, bleeding, fistula, or extraction-site injury.
30 days after surgery
Length of Hospital Stay
Time Frame: From date of surgery until hospital discharge, up to 30 days
Length of postoperative inpatient hospital stay following index colorectal surgery.
From date of surgery until hospital discharge, up to 30 days
EQ-5D-5L Score
Time Frame: Baseline, 6 months, and 12 months after surgery
Health-related quality-of-life assessed using the EuroQol 5-Dimension 5-Level (EQ-5D-5L) questionnaire.
Baseline, 6 months, and 12 months after surgery
Body Image Scale (BIS) Score
Time Frame: Baseline, 6 months, and 12 months after surgery
Body image assessed using the Body Image Scale (BIS).
Baseline, 6 months, and 12 months after surgery
Low Anterior Resection Syndrome (LARS) Score
Time Frame: 6 months and 12 months after surgery
Bowel function assessed using the Low Anterior Resection Syndrome (LARS) score.
6 months and 12 months after surgery
Local Recurrence
Time Frame: Up to 24 months after surgery
Incidence of local recurrence following minimally invasive colorectal surgery.
Up to 24 months after surgery
Distant Recurrence
Time Frame: Up to 24 months after surgery
Incidence of distant recurrence following minimally invasive colorectal surgery.
Up to 24 months after surgery
Disease-Free Survival
Time Frame: Up to 24 months after surgery
Time from index colorectal surgery to recurrence or death from any cause.
Up to 24 months after surgery

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Singapore General Hospital

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

May 5, 2026

Primary Completion (Estimated)

March 30, 2033

Study Completion (Estimated)

December 30, 2033

Study Registration Dates

First Submitted

May 19, 2026

First Submitted That Met QC Criteria

May 22, 2026

First Posted (Actual)

May 29, 2026

Study Record Updates

Last Update Posted (Actual)

May 29, 2026

Last Update Submitted That Met QC Criteria

May 22, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 2026-0237

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

UNDECIDED

IPD Plan Description

Individual participant data sharing plans have not yet been finalized. Future sharing of deidentified data may be considered following establishment of multicenter governance, data-sharing agreements, and publication policies.

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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