RecruitingPhase 2NCT06923345

Modified Long-Course Radiotherapy Followed by Chemotherapy and PD-1 Inhibitor for MSS/pMMR High-risk Mid/Low LARC (MODIFI-RC-I)

Modified Long-Course Radiotherapy (Reduced vs. Conventional CTV), Sequential Chemotherapy and PD-1 Inhibitor in Locally Advanced, MSS, Mid-Low Rectal Cancer: An Open-Label, Two-Arm, Randomized, Prospective Phase II Clinical Trial (MODIFI-RC-I)

Sponsor

Sixth Affiliated Hospital, Sun Yat-sen University

Enrollment

80 participants

Start Date

Mar 31, 2025

Study Type

INTERVENTIONAL

Conditions

Rectal Cancer Radiotherapy Neoadjuvant Therapies Immune Checkpoint Therapy

Summary

The goal of this clinical trial is to evaluate whether a total neoadjuvant therapy (TNT) regimen combining long-course chemoradiotherapy, sequential chemotherapy, and PD-1 inhibitor can improve response rates, enhance tolerability, and improve prognosis in patients with locally advanced, microsatellite-stable (MSS) rectal cancer. The main questions it aims to answer are: Does this TNT approach improve complete response (CR) rates? How does selective reduction of clinical target volume (CTV) to S2/S3 level compare with conventional CTV irradiation in terms of efficacy and safety? Researchers will compare a selective CTV reduction group and a conventional CTV irradiation group to assess differences in treatment outcomes, including complete response, tumor regression grading (TRG), organ preservation, R0 resection rates, and long-term survival. Participants will: Receive long-course chemoradiotherapy with either conventional or reduced CTV irradiation. Undergo sequential chemotherapy. Receive PD-1 inhibitor treatment. Be monitored for safety, tumor regression, and long-term survival outcomes.

Eligibility

Min Age: 18 YearsMax Age: 75 Years

Plain Language Summary

Simplified for easier understanding

This study is testing a modified radiation therapy schedule followed by chemotherapy and an immunotherapy drug (PD-1 inhibitor) for people with locally advanced rectal cancer. The treatment is specifically for cancer that has specific genetic features (MSS/pMMR) and is located in the lower rectum. **You may be eligible if...** - You are between 18 and 75 years old - You have confirmed rectal adenocarcinoma (rectal cancer) - Your cancer has not spread to other organs (locally advanced, stage II–III) - Your tumor is MSS/pMMR (confirmed by tissue testing) - Your cancer is located below the peritoneal fold and a surgeon has evaluated you as a surgical candidate **You may NOT be eligible if...** - Your cancer has spread to other organs (metastatic) - Your cancer is MSI-H (a different genetic profile) - You have serious heart, immune, or organ conditions - You are pregnant or breastfeeding Talk to your doctor to see if this trial is right for you.

This summary was AI-generated to explain the trial in plain language. It is not medical advice. Always discuss eligibility with your doctor before enrolling in a clinical trial.

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Interventions

COMBINATION_PRODUCTReduced CTV

Long-course radiotherapy with selective CTV reduction (lower to S2/S3 level) + CAPOX + PD-1 inhibitor. After treatment, patients will undergo TME surgery or a watch-and-wait approach, depending on response.

COMBINATION_PRODUCTConventional CTV

Long-course radiotherapy with conventional CTV irradiation + CAPOX + PD-1 inhibitor. After treatment, patients will undergo TME surgery or a watch-and-wait approach, depending on response.