Endoscopic Therapy Or Surgery for Early Colon Cancer (ETHOS)

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: Colon Cancer
• Intervention / Treatment: Procedure: eFTR; Procedure: Surgery

• Study Type: Interventional
• Enrollment (Estimated): 434
• Phase: Phase 3

Contacts and Locations

• Study Contact: Name: MICHAEL BRETTHAUER, MD PhD; Phone Number: +4790132480; Email: michael.bretthauer@medisin.uio.no

Study Locations

• Poland
  • Gdansk, Poland
    • Recruiting
    • Medical University of Gdansk
    • Contact: Piotr Spychalski, MD PhD; Phone Number: 90132480; Email: piotr.spychalski@gmail.com

Participation Criteria

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

How is the study designed?

Design Details

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

Number of Arms

2

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	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	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

• 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

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: Neoplasms by Site; Neoplasms; Intestinal Diseases; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Colorectal Neoplasms; Intestinal Neoplasms; Colonic Diseases; Colonic Neoplasms; Surgical Procedures, Operative
• 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