Node-Sparing Low-Dose Radiotherapy Concurrent With Chemotherapy and PD-1 Inhibitor in pMMR/MSS High-Risk Locally Advanced Colon Cancer: A Prospective, Single-Arm, Phase II Trial

Sponsor
Sixth Affiliated Hospital, Sun Yat-sen University
Study ID
NCT07279077
Phase
PHASE2
Status
Recruiting
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Conditions

  • Colon Cancer
  • Immune Checkpoint Therapy
  • Neoadjuvant Therapies
  • Radiation Therapy

Eligibility Criteria

Sex
ALL
Age
18 Years - 75 Years
Healthy Volunteers
Not accepted

Interventions

  • Node-Sparing Low-Dose Radiotherapy Concurrent With Chemotherapy and PD-1 Inhibitor — COMBINATION_PRODUCT
    Patients will receive 4 cycles of neoadjuvant therapy: In D1, D2: node-sparing low-dose radiotherapy (1Gy\*2d), concurrent with CAPOX chemotherapy and PD-1 inhibitor(200mg). After that, patients will undergo partial colectomy at the site of tumor.

Study Details

Most colorectal cancers belong to the microsatellite stable (MSS) or proficient mismatch repair (pMMR) subtypes, with limited response to PD-1 inhibitors. Radiotherapy can increase the release of tumor-associated antigens, thereby improve responsiveness to PD-1 blockade in MSS/pMMR rectal cancer. Tumor-draining lymph nodes are important sites for PD-1 inhibitors to exert antitumor effects, and studies have reported that direct radiation-induced damage and fibrosis can inhibit lymph node drainage and anti-tumor function. Accumulating evidence indicates that low-dose radiotherapy reprograms the tumor microenvironment (TME), transforming immunosuppressive 'cold' tumors into immunostimulatory 'hot' tumors. This transition is mediated by modulating the gut microbiota, eliciting innate and adaptive immune responses, inhibiting immunosuppressive cells, and promoting the infiltration of T and B lymphocytes.Therefore, this study aims to evaluate whether node-sparing low-dose radiotherapy (1Gy/8f) concurrent with chemotherapy and PD-1 inhibitor can improve the pathological complete response (pCR) rate, enhance tolerability, and improve prognosis in patients with pMMR/MSS high-risk locally advanced colon cancer.

Key Dates

First listed
Dec 12, 2025
Start date
Nov 26, 2025
Status verified
Dec 2025
Primary completion
Nov 25, 2030
Completion
Dec 30, 2031

Study Design

Enrollment
38 participants (estimated)
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT

Arms

  • Experimental: Node-sparing Low-Dose Radiotherapy Concurrent With Chemotherapy and PD-1 Inhibitor
    D1, D2: Node-sparing low-dose radiotherapy (1GY\*2d) concurrent with chemotherapy (CAPOX) and PD-1 Inhibitor (200mg). 4 cycles, q3w, as total neoadjuvant therapy

Primary Outcome Measure

Pathological Complete Response(pCR) Rate [ Time Frame: From enrollment to 2-4 weeks after surgery ]

Central Contacts

  • Yanxin Luo, M.D., Ph.D.
    +86-20-38254221
    [email protected]
  • Yikan Cheng, M.D., Ph.D.
    15102033641

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