Endoscopic Therapy Or Surgery for Early Colon Cancer (ETHOS)

November 17, 2025 updated by: Michael Bretthauer, Norwegian Department of Health and Social Affairs

Endoscopic THerapy Or Surgery for Early Colon Cancer (ETHOS)

The trial is a randomized head-to-head comparison of the benefits, harms and burdens of endoscopic full-thickness resection (eFTR), a novel, minimally invasive endoscopic treatment modality, for early colon cancer as compared to standard-of-care surgery.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

434

Phase

  • Phase 3

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

  • Child
  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Newly diagnosed biopsy-confirmed colon cancer (adenocarcinoma) with macroscopic suspicion of submucosal invasion considered removable by EFTR as deemed by the local multidisciplinary team (MDT) at the participating center
  • Size ≤20 mm in diameter as deemed by the colonoscopist
  • No presence of histopathological high-risk features in biopsy (high grade tumor growth, budding grade 2 or 3, or lymphovascular invasion)
  • Patient eligible for surgical removal as deemed by the local MDT at the participating center
  • Endoscopic images or video of the tumor
  • No sign of disease beyond T2N0M0 on pre-treatment imaging, biopsy sampling, and radiographic and clinical evaluation
  • No contraindication for any of the two treatment arms
  • Written informed consent
  • No prior or synchronous CRC
  • No other malignancy which is not cured
  • No more than 10 adenomas or serrated polyps
  • No genetic cancer syndrome (adenomatous or serrated polyposis syndrome; Lynch or Lynch-like syndrome)
  • No inflammatory bowel disease

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

  • Primary Purpose: Treatment
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Single

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: eFTR
endoscopic full thickness resection
Procedure: eFTR
endoscopic full thickness resection
Active Comparator: Surgery
standard-of-care surgery
Procedure: Surgery
standard-of-care surgery

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Rate of severe adverse events, re-admissions and deaths within 30 days
Time Frame: 30 days
co-primary short-term endpoint is the composite rate of rate of severe adverse events, re-admissions and deaths within 30 days following assigned treatment
30 days
Rate of cancer recurrence or CRC death after three years
Time Frame: 3 years
primary long-term endpoint of CRC death or cancer recurrence or sign of lymph nodes or distant metastases after three years
3 years

Collaborators and Investigators

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

Sponsor

Norwegian Department of Health and Social Affairs

Collaborators

Vestre Viken Hospital Trust
University of Oslo
Karolinska Institutet
University of Roma La Sapienza
Hospital Clinic of Barcelona
Helse Stavanger HF
Haukeland University Hospital
St. Olavs Hospital
University Hospital, Limoges
University Hospital, Ghent
University Hospital, Akershus
Medical University of Gdansk
Medical Biometry and Epidemiology_- Universitätsklinikum Hamburg Eppendorf
Leuven University Medical Center
Sørlandet Hospital
Institute of Oncology in Warsaw
Northern Norway Regional Health Trust
Frontier Science Foundation

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)

August 25, 2025

Primary Completion (Estimated)

September 1, 2033

Study Completion (Estimated)

September 1, 2033

Study Registration Dates

First Submitted

April 15, 2025

First Submitted That Met QC Criteria

April 15, 2025

First Posted (Actual)

April 23, 2025

Study Record Updates

Last Update Posted (Actual)

November 20, 2025

Last Update Submitted That Met QC Criteria

November 17, 2025

Last Verified

November 1, 2025

More Information

Terms related to this study

Additional Relevant MeSH Terms

Other Study ID Numbers

  • 840389

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

Only if ethical approval is granted by the other researchers, and the study scientific board has reviewed and approved the proposal

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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