NCT07080411

the Efficacy of MR-guided Online Adaptive Radiotherapy for Locally Advanced Rectal Cancer

A Prospective Study on the Efficacy of MR-guided Online Adaptive Radiotherapy for Locally Advanced Rectal Cancer

• Status: Not Yet Recruiting
• Phase: N/A
• Study type: Interventional
• Enrollment: 49 (estimated)
• Sponsor: Cancer Institute and Hospital, Chinese Academy of Medical Sciences · Academic / Other
• Sex: All
• Age: 18 Years – 75 Years
• Healthy volunteers: Not accepted

Summary

Based on preliminary findings on the motion error of the clinical target volume (CTV) in MR-guided adaptive radiotherapy (MRgART) for locally advanced rectal cancer (LARC), this study aims to reduce CTV-to-PTV margins and evaluate the complete response (CR) rate following MRgART in LARC patients. Additionally, it will investigate the safety and tolerability of MRgART, as well as its impact on: 3-year organ preservation rate Local recurrence rate in patients under a "watch-and-wait" approach 3-year overall survival (OS), disease-free survival (DFS), and local progression-free survival (LPFS). Furthermore, by analyzing ADC maps of the gross tumor volume (GTV), this study will characterize treatment responses and spatial deformation in metabolically active tumor subregions. These insights may inform future dose-escalation strategies for LARC radiotherapy, with the ultimate goal of improving prognosis and quality of life in this patient population.

Conditions

• Rectal Cancer
• Adaptive Radiotherapy

Interventions

Type	Name	Description
RADIATION	short course radiotherapy using MR-linac	Patients in the MRgART group will receive standard total neoadjuvant therapy (TNT) and surgical treatment, including short-course radiotherapy and chemotherapy, with the addition of immunotherapy at the investigator's discretion based on individual patient characteristics.

Timeline

• Start date: 2025-08-01
• Primary completion: 2026-12-31
• Completion: 2029-12-31
• First posted: 2025-07-23
• Last updated: 2025-07-23