SCAR

StartSCAR

SCAR Study Recruiting

Lead: National Research Institute of Oncology, Warsaw PI: Nastazja Dagny Pilonis 304 patients 5-year follow-up

Surgery vs. Endoscopic Resection for Incompletely Removed Early Colon Cancer — a randomized trial asking a critical question: after incomplete removal of early colon cancer, is surgery always necessary?

SCAR focuses on a common and difficult situation in colorectal cancer care. A patient undergoes a routine colonoscopy, has what appears to be a polyp removed, and only later learns from the pathology report that it was early cancer — incompletely removed.

Current guidelines recommend surgery. Yet in most cases, no residual tumour is found in the surgical specimen. SCAR evaluates whether a second, targeted endoscopic procedure could safely replace it.

The clinical dilemma

This is not a rare or theoretical scenario. Many early colon cancers are initially removed during routine colonoscopy because they appear to be benign polyps. The real diagnosis becomes clear only after histopathological assessment.

From that point, the standard pathway is usually straightforward: surgery is recommended. Yet for many patients, that means bowel resection, hospitalization, and recovery for disease that may no longer be present.

SCAR addresses a central ECOPOP question in a specific clinical setting: where is the line between necessary treatment and overtreatment?

Why this question matters

A frequent real-world scenario

Incomplete resection of early colon cancer after routine polypectomy is a well-recognized clinical situation created by the increasing detection of early lesions through colonoscopy and screening.

Possible overtreatment

Surgery is currently recommended, but in most patients no residual tumour is found. SCAR asks whether some patients are being exposed to surgical burden unnecessarily.

Randomized evidence is missing

Current practice is guided by caution, not by randomized comparison. SCAR is the first trial designed to provide high-level evidence in this exact clinical setting.

Clinical decisions could change

If endoscopic completion treatment proves safe, the study could support a more precise, less invasive pathway for selected patients with early colon cancer.

What the trial compares

Endoscopic full-thickness resection (eFTR)

  • Minimally invasive completion treatment
  • Targets the previous resection site directly
  • Avoids bowel resection if sufficient
  • May reduce recovery burden and procedure-related complications

Standard surgical resection

  • Current guideline-recommended approach
  • Requires removal of a bowel segment
  • Associated with hospitalization and longer recovery
  • Often finds no residual tumour in the specimen

Primary hypothesis: eFTR is non-inferior to surgery for cancer recurrence at 1 year and superior in reducing severe adverse events within 30 days.

Beyond clinical outcomes

SCAR evaluates more than oncological safety alone. Within ECOPOP, the trial also contributes to the assessment of treatment burden, cost-effectiveness, and environmental impact. This allows comparison of the two strategies not only in terms of cancer outcomes, but also in terms of what they demand from patients and healthcare systems.

Study design & key details

Design

Randomized, controlled, multicentre, international trial.

Target enrollment

304 patients (152 per arm) across sites in Norway, Poland, Germany, Italy, France, Spain, Belgium, and Sweden.

Primary endpoints

Cancer recurrence at 1 year and severe adverse events within 30 days.

Follow-up

5 years, with additional analyses including long-term outcomes, cost-effectiveness, and ecological footprint.

Who can participate

Participation is voluntary and assessed by the clinical team at a participating site. SCAR is intended for a specific group of patients whose cancer was unexpectedly identified after routine colonoscopic removal.

Key inclusion criteria

  • age 40 years or older;
  • prior endoscopic removal of early colon cancer with incomplete resection margins (R1 or Rx);
  • lesion located in the colon (at least 12 cm from the anal verge);
  • no high-risk histopathological features;
  • no evidence of disease beyond T1N0M0;
  • identifiable resection site at follow-up colonoscopy.

Key exclusion criteria

  • rectal location (less than 12 cm from the anal verge);
  • complete prior resection (R0);
  • confirmed high-risk features such as poor differentiation, lymphovascular invasion, or high-grade tumour budding;
  • evidence of more advanced disease than T1N0M0;
  • non-identifiable scar or resection site preventing completion treatment assessment.

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

Project team

Principal Investigator
Nastazja Dagny Pilonis MD PhD · Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Co-Principal Investigators
Michael Bretthauer Professor · University of Oslo / Oslo University Hospital, Norway
Michał F. Kamiński Professor · Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw, Poland
Thomas Rösch Professor · University Hospital Hamburg-Eppendorf, Germany
Giulio Antonelli MD PhD · Sapienza University of Rome, Italy
Jens Aksel Nilsen MD PhD · Oslo University Hospital, Norway
Linn Bernklev MD · Akershus University Hospital / University of Oslo, Norway
Jérémie Jacques MD · Dupuytren University Hospital, Limoges, France
Main Investigators
Jarosław Kobiela MD PhD · Medical University of Gdańsk, Poland
Maria Pellisé MD PhD · Hospital Clínic de Barcelona, Spain
Collaborating institutions
Maria Skłodowska-Curie National Research Institute of Oncology, Warsaw · Oslo University Hospital / University of Oslo · University Hospital Hamburg-Eppendorf · Sapienza University of Rome · Karolinska Institutet · Humanitas University · UZ Leuven · Hospital Clínic de Barcelona

Interested in joining or referring a patient?

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

Trial at a glance
Status ● Recruiting
Patients 304 (152 per arm)
Primary endpoint 1 year
Follow-up 5 years
Work package WP2
Lead institution NIO Warsaw
Want to refer a patient or join SCAR?

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

Contact the team
Other ECOPOP trials
ETHOS Trial T-REX Trial
Contact

Questions about participation or site referral?

Email:
ecopop@gumed.edu.pl

Location:
Medical University of Gdańsk