MR‑guided short‑course radiation with chemotherapy and surgery for unresectable locally advanced colon cancer

Study on the Safety and Efficacy of MR-Linac Technique in Patients With Unresectable Locally Advanced Colon Cancer

This trial will test whether MR‑Linac short‑course radiotherapy followed by chemotherapy and surgery can help people with T4 unresectable locally advanced colon cancer achieve complete tumor removal and better outcomes.

Quick facts

• Phase: Not applicable
• Study type: Interventional
• Enrollment: 20 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Sichuan Cancer Hospital and Research Institute (Academic / other)
• Drugs / interventions: chemotherapy
• Locations: 1 site (Chengdu, Sichuan)
• Trial ID: NCT06244537 on ClinicalTrials.gov

What this trial studies

This single‑arm phase I study will enroll about 20 patients with cT4N0‑2M0 colon adenocarcinoma to receive MR‑Linac adaptive short‑course radiotherapy (25 Gy in 5 fractions), followed by neoadjuvant chemotherapy (mFOLFOX6 or XELOX), radical surgery, and postoperative chemotherapy. The study will track surgical R0 resection rate, pathologic or clinical complete response rates, progression‑free and overall survival, and treatment‑related adverse events. An initial run‑in feasibility phase will monitor protocol adherence, adaptive‑plan success, and accrual before proceeding to the definitive phase. The design focuses on safety, technical feasibility of the MR‑Linac workflow, and early signals of efficacy in converting unresectable tumors to resectable status.

Who should consider this trial

Good fit: Adults (≥18) with pathologically confirmed colon adenocarcinoma staged cT4N0‑2M0, ECOG 0–1, adequate blood and organ function, able to tolerate MRI and remain still for 1–1.5 hours, and willing to follow the protocol are ideal candidates.

Not a fit: Patients with dMMR/MSI‑H, distant metastases, inability to undergo MRI (including claustrophobia or incompatible implants), prior anti‑tumor therapy, pregnancy/lactation, or poor performance status are unlikely to benefit or be eligible.

Why it matters

Potential benefit: If successful, the approach could increase the chance of converting unresectable tumors to resectable ones, raise R0 resection and complete response rates, and potentially improve survival with acceptable toxicity.

How similar studies have performed: Adaptive MR‑guided radiotherapy has shown promising early results in other abdominal and pelvic cancers, but using MR‑Linac specifically to convert unresectable colon cancer to resectable is relatively novel and not yet proven.

Eligibility criteria

Inclusion criteria:

1. Patients over 18 years old
2. Patients can remain in a stationary position on the treatment bed for 1-1.5 hours
3. ECOG score 0-1
4. Pathological diagnosis of colon adenocarcinoma, clinical stage cT4N0-2M0
5. Organ function is normal, and the following conditions are required: white blood cell count ≥3.5×10\^9/L; platelet count ≥100×10\^9/L; hemoglobin ≥90g/L. Total bilirubin level ≤1.5× upper limit of normal (ULN); AST and ALT levels ≤2.5 × ULN; endogenous creatinine clearance rate: 56-122ml/min; serum creatinine \<1.0× ULN; serum albumin ≥30g/L.
6. Able to adhere to the study protocol during the research period
7. Signed written informed consent

Exclusion Criteria:

1. Patients with dMMR or MSI-H
2. Presence of other types of tumors in addition to colon adenocarcinoma
3. Claustrophobia or inability to undergo MRI or treatment due to the presence of metal implants or other reasons
4. Distant metastasis (M1)
5. Pregnant or lactating women
6. Previous anti-tumor treatment
7. Concurrent use of prohibited drugs for treatment
8. Known history of positive human immunodeficiency virus testing or known acquired immunodeficiency syndrome.
9. Clinically significant (i.e., active) cardiovascular disease: cerebrovascular accident/stroke (\<6 months prior to enrollment), myocardial infarction (\<6 months prior to enrollment), unstable angina pectoris, congestive heart failure (≥New York Heart Association class II) or severe arrhythmia requiring medication treatment
10. Individuals with uncontrolled epilepsy, central nervous system disorders or a history of mental illness, whose clinical severity may hinder signing informed consent or affect patient compliance with oral medication according to the investigator's judgement
11. Organ transplant surgery requiring immunosuppressive therapy
12. Severe, uncontrolled recurrent infections or other severe, uncontrolled comorbidities

Where this trial is running

Chengdu, Sichuan

• Sichuan Cancer Hospital & Institute, Affiliated Cancer Hospital of University of Electronic Science and Technology of China. — Chengdu, Sichuan, China (Recruiting)

Study contacts

• Study coordinator: Qian - Peng, chief physician

Conditions Safety and Efficacy; MR-Linac; unresectable locally advanced colorectal cancer; neoadjuvant radiotherapy