Active Surveillance vs Adjuvant Chemoradiotherapy for Locally Resected Intermediate-Risk T1 Rectal Cancer

Summary

The goal of this clinical trial is to learn if close follow-up alone (active surveillance) works as well as radiation combined with chemotherapy (chemoradiotherapy) after removing early rectal cancer in adults. The main questions it aims to answer are:

1. Does active surveillance cause fewer serious adverse events than chemoradiotherapy within 3 years? Serious adverse events include a permanent or temporary ostomy (a surgical opening in the belly to pass stool), major bowel problems, or severe treatment-related complications.
2. Is active surveillance as safe as chemoradiotherapy in preventing cancer from coming back or spreading within 3 years?

Researchers will compare active surveillance to chemoradiotherapy to see if surveillance causes fewer serious adverse events while keeping cancer outcomes comparable.

To join this study, participants must be adults who had an early-stage rectal cancer (T1) removed by an endoscopic procedure, and whose removed tumor showed certain features that raise the risk of cancer cells remaining nearby.

Participants will be randomly placed in one of two groups:

1. Active surveillance group: Participants will have regular checkups, blood tests, flexible camera exams of the bowel (rectoscopy), scans of the pelvis and abdomen, and colonoscopy on a set schedule for 5 years. If cancer comes back, doctors will propose further treatment options.
2. Chemoradiotherapy group: Participants will receive radiation to the pelvis along with a chemotherapy pill (capecitabine) or an intravenous (IV) chemotherapy drug (5-FU) for about 5 weeks. After treatment, they will have regular checkups and scans for 5 years.

Conditions

• Rectal Cancer

Interventions

OTHER

Active surveillance

Active surveillance includes physical examination, and carcinoembryonic antigen (CEA) testing every 3 months during years 1-2 and every 6 months during years 3-5. Rectoscopy is performed every 3 months during years 1-2 and every 6 months during years 3-5. Pelvic MRI is performed every 6 months for 5 years. Thoracic and abdominal CT scans are performed annually for 5 years. Colonoscopy is performed at 1 year after local excision and subsequently according to findings. Recurrences are managed according to multidisciplinary team recommendations.

RADIATION

Adjuvant chemoradiotherapy

Adjuvant long-course pelvic chemoradiotherapy will be initiated within 12 weeks after local excision. Radiotherapy consists of 45 Gy delivered in 25 fractions of 1.8 Gy once daily, 5 days per week, over approximately 5 weeks. Concurrent chemotherapy consists of either oral capecitabine 825 mg/m² twice daily on radiotherapy days or continuous intravenous 5-fluorouracil 225 mg/m²/day throughout radiotherapy. After treatment, follow-up includes history, physical examination, CEA testing, and flexible sigmoidoscopy every 6 months for 5 years; pelvic MRI every 6 months during the first 3 years; annual thoracic and abdominal CT for 5 years; pelvic CT after discontinuation of MRI surveillance; and colonoscopy at 1 year and thereafter according to findings.

Sponsors & Collaborators

• University of Oslo

  collaborator OTHER

• Maria Sklodowska-Curie National Research Institute of Oncology

  collaborator OTHER

• Centre Hospitalier Universitaire Dupuytren de Limoges (CHUL)

  collaborator UNKNOWN

• Vestre Viken Hospital Trust

  collaborator OTHER

• Universitätsklinikum Hamburg-Eppendorf

  collaborator OTHER

• Karolinska Institutet

  collaborator OTHER

• University Hospital, Akershus

  collaborator OTHER

• University of Roma La Sapienza

  collaborator OTHER

• Hospital Clinic of Barcelona

  collaborator OTHER

• Leuven University Medical Center

  collaborator UNKNOWN

• University Hospital, Ghent

  collaborator OTHER

• Sorlandet Hospital HF

  collaborator OTHER_GOV

• Northern Norway Regional Health Trust

  collaborator UNKNOWN

• Helse Stavanger HF

  collaborator OTHER_GOV

• Haukeland University Hospital

  collaborator OTHER

• St. Olavs Hospital

  collaborator OTHER

• Medical University of Gdansk

  lead OTHER

Study Design

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

NONE

Model

PARALLEL

Eligibility

Min Age

18 Years

Sex

ALL

Healthy Volunteers

No

Timeline & Regulatory

Start

2026-06-14

Primary Completion

2037-06-30

Completion

2037-06-30

Countries

• France
• Poland

Study Locations