NCT06898359

Role of Gut Microbiota in Neoadjuvant Radioimmunotherapy for MSS, Locally Advanced Rectal Cancer

Role of Gut Microbiota in Neoadjuvant Radioimmunotherapy for MSS, Locally Advanced Rectal Cancer: A Single-Center, Observational Study

• Status: Completed
• Phase: —
• Study type: Observational
• Enrollment: 29 (actual)
• Sponsor: Yanhong Deng · Academic / Other
• Sex: All
• Age: 18 Years – 65 Years
• Healthy volunteers: Not accepted

Summary

This research investigates the role of the gut microbe in patients receiving radioimmunotherapy with locally advanced microsatellite-stable (MSS) rectal cancer. Given the limitations of current treatment strategies in achieving optimal clinical outcomes, this prospective, single-center, phase II clinical trial aims to improve pathological complete response (pCR) rates. The primary endpoint is pCR, with secondary endpoints including disease-free survival (DFS) and the incidence of treatment-related adverse events. This study seeks to provide insights into a novel treatment paradigm for MSS locally advanced rectal cancer, potentially offering improved therapeutic options for this patient population.

Detailed description

Locally advanced rectal cancer (LARC) presents a complex treatment challenge, often requiring a multimodal approach to achieve optimal cure rates and improve survival. Currently, the combination of short-course radiotherapy (SCRT) and neoadjuvant chemotherapy has become a critical treatment strategy for LARC patients. Compared to conventional long-course radiotherapy (LCRT), SCRT is associated with a shorter treatment duration, typically lasting only five days, which facilitates rapid tumor shrinkage and minimizes surgical delays. This expedited treatment approach not only reduces the risk of postponing surgery but also improves the management of patients by minimizing fatigue and treatment-related side effects associated with longer regimens. Despite the promising outcomes associated with SCRT and neoadjuvant chemotherapy, a significant proportion of patients still do not achieve satisfactory clinical responses to standard treatment regimens. In recent years, the emergence of immune checkpoint inhibitors has revolutionized cancer treatment. In particular, PD-1 inhibitors such as Sintilimab have demonstrated significant antitumor activity across various solid tumors, notably in microsatellite instability-high (MSI-H) cancers. However, the potential benefits of these agents in microsatellite-stable (MSS) rectal cancer remain insufficiently explored. This study aims to investigate the effects of radioimmunotherapy in a single-center cohort for MSS locally advanced rectal cancer. We hope to provide a novel therapeutic option that enhances clinical efficacy for patients with LARC by evaluating the differences in the gut microbiota in those patients with pCR vs no-pCR response.

Conditions

• Rectal Cancer

Interventions

Type	Name	Description
RADIATION	Radioimmunotherapy	SCRT (a total of 25 Gy in 5 days) followed by sintilimab (3mg/kg intravenous drip on day 1; every 3-week cycle for two cycles)

Timeline

• Start date: 2022-05-20
• Primary completion: 2023-07-03
• Completion: 2023-08-28
• First posted: 2025-03-27
• Last updated: 2025-03-27

Locations

1 site across 1 country: China