ETHOS

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ETHOS Trial Recruiting

Lead: University of Oslo PI: Michael Bretthauer Recruitation goal: 438 patients 5-year follow-up

Surgery vs. Endoscopic Resection for Early Colon Cancer — a randomized trial asking a critical question: can early colon cancer be treated with less burden, without compromising oncological safety?

ETHOS focuses on a growing challenge in colorectal cancer care. Screening programmes are detecting more early colon cancers, yet the current standard treatment remains surgery.

Surgery is effective, but it is also invasive, resource-intensive, and associated with complications and recovery burden. ETHOS evaluates whether a minimally invasive endoscopic procedure could safely replace surgery in selected patients with early-stage colon cancer.

ETHOS is currently expanding across Europe. New clinical centres are actively joining the trial as study sites, alongside ongoing patient recruitment at existing centres.

The clinical dilemma

For many patients with early colon cancer, the standard pathway still means removal of a segment of the bowel together with adjacent lymph nodes. Yet most patients with early-stage disease do not have nodal or distant metastases.

This creates a central clinical question: when is surgery necessary, and when might it represent more treatment than the patient actually needs? ETHOS addresses this question directly in patients with early colon cancer eligible for both approaches.

ETHOS addresses a central ECOPOP question in a specific clinical setting: can treatment be made less invasive without losing oncological safety?

Why this question matters

Addressing a growing problem

Screening programmes are detecting more early colon cancers. This means that decisions about how much treatment is truly necessary will affect a growing number of patients.

Reducing treatment burden

Current standard surgery is effective, but it carries complication risk, requires hospitalization, and places a significant burden on patients. Less invasive treatment could change that balance.

Patient-centred outcomes

ETHOS looks beyond cancer control alone. The trial also considers adverse events, quality of life, patient burden, treatment costs, and organ preservation.

Evidence for practice change

Broad implementation of less invasive treatment requires high-quality randomized evidence. ETHOS is designed to provide exactly that in early colon cancer.

What the trial compares

Endoscopic full-thickness resection (eFTR)

  • Minimally invasive treatment performed endoscopically
  • No surgical incision
  • May reduce procedure burden and recovery time
  • Aims to preserve the colon when sufficient

Standard surgical resection

  • Current standard of care for early colon cancer
  • Removal of a bowel segment with lymph nodes
  • Associated with longer recovery and higher complication risk
  • Reference approach in the trial

Study hypothesis: eFTR provides similar oncological outcomes and a lower risk of adverse events compared with surgery.

Beyond clinical outcomes

ETHOS evaluates more than technical success or recurrence alone. Within ECOPOP, the trial also contributes to the assessment of patient burden, quality of life, treatment costs, and environmental footprint. This allows comparison of the two strategies in terms that matter both clinically and practically.

Study design & key details

Design

Randomized, controlled, multicentre, international trial.

Target enrollment

438 patients across active study sites in Europe.

Primary endpoints

Moderate or severe adverse events within 30 days, and cancer recurrence or signs of metastases after 3 years.

Current status

Actively recruiting, with sites already engaged and patients randomized and treated. New sites continue to join.

Who can participate

Participation is voluntary and eligibility is assessed by the clinical team at a participating study site. ETHOS is intended for patients with early colon cancer who are technically eligible for both endoscopic and surgical treatment.

Key inclusion criteria

  • newly diagnosed early-stage colon cancer;
  • clinical stage cT1N0M0;
  • macroscopic features of deep submucosal invasion;
  • lesion technically eligible for eFTR;
  • tumour size of 20 mm or less;
  • eligibility confirmed by a multidisciplinary tumour board.

Key exclusion criteria

  • to be completed based on the full protocol / communication-approved criteria.

How to participate

Patients are referred through participating clinical centres and assessed locally for eligibility before enrolment. Referral from a treating physician at an active study site is required.

Final eligibility is always determined individually by the study team according to the full protocol and clinical assessment.

Project team

Principal Investigator
Michael Bretthauer Professor · University of Oslo, Norway
Co-Principal Investigators
Jens Aksel Nordberg Nilsen MD PhD · University of Oslo, Norway
Piotr Spychalski MD PhD · Medical University of Gdańsk, Poland
Main Investigators
Nastazja Dagny PilonisMD PhD · Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Michał F. KamińskiProfessor · Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Thomas RöschMD PhD · University Hospital Hamburg-Eppendorf, Germany
Giulio AntonelliMD PhD · Sapienza University of Rome, Italy
Jérémie JacquesMD PhD · CHU Limoges, France
Maria PelliséMD PhD · Hospital Clínic de Barcelona, Spain
David TateMD PhD · UZ Gent, Belgium
Investigators
Mette KalagerMD PhD · Oslo University Hospital / University of Oslo, Norway
Øyvind HolmeMD PhD · Sørlandet Hospital, Kristiansand, Norway
Magnus LøbergMD PhD · Oslo University Hospital / University of Oslo, Norway
Hans-Olov AdamiMD PhD · Oslo University Hospital / Karolinska Institutet
Linn BernklevMD · Akershus University Hospital / University of Oslo, Norway
Henriette JodalMD PhD · Vestre Viken Hospital / University of Oslo, Norway
Sandra NaglMD PhD · University of Augsburg, Germany
Helmut MessmannMD PhD · University of Augsburg, Germany
Alanna EbigboMD PhD · Ruhr University Bochum, Germany
Jasmin Zessner-SpitzenbergMD PhD · University of Oslo, Norway
Johannes BlomMD PhD · Karolinska Institutet, Sweden
Diba AinechiUniversity of Oslo, Norway
Trial Management & Statistics
Madeleine SkotnesMSc · Trial Manager · University of Oslo, Norway
Linn FolkenborgMSc · Trial Manager · University of Oslo, Norway
Anna MaciosPhD · Study Statistician · University of Oslo, Norway
Siv IsaksenRN · Study Nurse · University of Oslo, Norway

Interested in joining or referring a patient?

Clinical centres interested in joining ETHOS as study sites, or physicians wishing to refer eligible patients, are welcome to contact the coordination team.

Trial at a glance
Status ● Recruiting
Patients to rectruit 438
Follow-up 5 years
Lead institution University of Oslo
Want to refer a patient or join ETHOS?

Clinical centres interested in joining ETHOS as study sites, or physicians wishing to refer eligible patients, are welcome to contact the coordination team.

Contact the team
Other ECOPOP trials
SCAR Study T-REX Trial
Contact

Questions about participation or site referral?

Email:
ecopop@gumed.edu.pl

Location:
Medical University of Gdańsk