Preserving the rectum with higher-dose MRI-guided adaptive radiotherapy

Organ Preservation in Rectal Cancer by Dose Escalated MR Guided Adaptive Radiotherapy

This tests whether higher-dose MRI-guided adaptive radiotherapy with standard chemotherapy can help people with distal rectal cancer keep their rectum.

Quick facts

• Phase: PHASE2
• Study type: Interventional
• Enrollment: 100 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: University Hospital Tuebingen (other)
• Drugs / interventions: chemotherapy, radiation
• Locations: 1 site (Tübingen, Baden-Wurttemberg)
• Trial ID: NCT07337876 on ClinicalTrials.gov

What this trial studies

This phase 2 interventional protocol delivers dose-escalated radiotherapy using a 1.5 T MR‑linac together with standard chemotherapy to patients with distal rectal cancer. MR-guided adaptive planning allows the team to shape and adjust high-dose radiation to the tumor while sparing normal tissue. Eligible patients are those with cT1–cT3, cN0–cN1, M0 tumors under specified size and circumferential limits who can undergo serial pelvic MRI. The main goal is a high rate of organ preservation (avoiding radical surgery) while monitoring for tumor control and treatment toxicity.

Who should consider this trial

Good fit: Adults (≥18) with distal rectal cancer staged cT1–cT3, cN0–cN1, M0 whose tumors involve less than 70% of the rectal circumference and are under 8 cm on MRI, with ECOG ≤1 and adequate organ function are the intended candidates.

Not a fit: Patients with T4 tumors, distant metastases, tumors ≥70% circumference or ≥8 cm, poor performance status, contraindications to MRI, or who require immediate surgery are unlikely to benefit.

Why it matters

Potential benefit: If successful, more patients could avoid radical surgery and permanent colostomy and preserve bowel function.

How similar studies have performed: Previous intensified chemoradiation approaches have shown promise for organ preservation, but MR-guided dose-escalated adaptive radiotherapy is a newer approach with limited published outcome data.

Eligibility criteria

Inclusion Criteria:

* Patients with histologically confirmed diagnosis of rectal cancer localized between dentate line and 12 cm from the anocutaneous line
* Any MRI staged rectal cancer meeting the following criteria
* cT1-cT3 and
* cN0 -cN1 and
* cM0
* Inclusion of UICC Stage I tumors only if unsuitable for endoscopic resection or if primary surgery would require permanent colostomy or deep anastomosis with expected poor organ function.
* Tumor affects less than 70% of the rectal circumference.
* Maximum longitudinal extension of the tumor less than 8 cm on MRI
* MR-Staging requirements: High-resolution, thin-sliced (i.e.

  ≤3mm) magnetic resonance imaging (MRI) of the pelvis.
* Cross-sectional imaging of the abdomen and chest to exclude distant metastases.
* Aged at least 18 years. No upper age limit.
* WHO/ECOG Performance Status ≤ 1
* Adequate hematological, hepatic, renal and metabolic function parameters
* Informed consent of the patient

Exclusion Criteria:

* Lower border of the tumor localised more than 12 cm from the anocutaneous line as measured by rigid rectoscopy
* Distant metastases
* Preexisting fecal incontinence for solid stool
* Prior antineoplastic therapy for rectal cancer
* Prior radiotherapy of the pelvic region
* Subject pregnant or breast feeding, or planning to become pregnant within 6 months after the end of treatment.
* Subject (male or female) is not willing to use highly effective methods of contraception (per institutional standard) during treatment and for 6 months (male or female) after the end of treatment (adequate: oral contraceptives, intrauterine device or barrier method in conjunction with spermicidal jelly).
* Other concomitant antineoplastic therapy
* Serious concurrent diseases, including neurologic or psychiatric disorders (incl. dementia and uncontrolled seizures), active,uncontrolled infections, active, disseminated coagulation disorder
* Other primary tumors with an estimated life expectancy of less than three years
* Contraindications for treatment with 5-Fluorouracil or Capecitabine
* Psychological, familial, sociological or geographical condition potentially hampering compliance with the study protocol and follow-up schedule (these conditions should be discussed with the patient before registration in the trial).

Where this trial is running

Tübingen, Baden-Wurttemberg

• University Hospital Tübingen — Tübingen, Baden-Wurttemberg, Germany (RECRUITING)

Study contacts

• Study coordinator: Cihan Gani, MD

Conditions: Rectal Cancer, organ preservation