NCT07200141

Simultaneous Boost in Neoadjuvant Radiotherapy for Rectal Cancer

Simultaneous Boost in Neoadjuvant Radiotherapy for Rectal Cancer：A Phase 2, Randomized Controlled Study

• Status: Not Yet Recruiting
• Phase: Phase 2
• Study type: Interventional
• Enrollment: 156 (estimated)
• Sponsor: Peking Union Medical College Hospital · Academic / Other
• Sex: All
• Age: 18 Years – 80 Years
• Healthy volunteers: Not accepted

Summary

The goal of this clinical trial is to learn whether new adjuvant radiotherapy with gross tumor volume(GTV) escalated to 58.75 Gy can improve complete response (CR) rates compared with GTV dose of 50 Gy in adult patients (18-79 years) with locally advanced rectal adenocarcinoma (T3-T4/N+, M0) located ≤10 cm from the anal verge.The main questions it aims to answer are: 1. Does GTV simultaneously boost to 58.75 Gy/25f increase complete response (pCR or cCR) compared with 50 Gy/25f? 2. How do the two regimens differ in terms of progression-free survival (PFS), pelvic local control (LC), tumor regression grade (TRG), organ preservation, and treatment-related toxicity? Researchers will compare GTV 58.75 Gy/25f (experimental arm) versus GTV 50 Gy/25f (control arm) to see if dose escalation improves tumor response rate. Participants will: 1. Receive neoadjuvant radiotherapy with one of the two PGTV dose escalated regimens (with concurrent chemotherapy: oral capecitabine or XELOX). 2. Undergo restaging with imaging and clinical assessment before surgery or observation. 3. Proceed to total mesorectal excision (TME), local excision, or "watch-and-wait" strategy depending on treatment response and patient preference. 4. Be followed regularly with clinical exams, imaging, endoscopy, and laboratory tests to assess efficacy, safety, and long-term outcomes.

Conditions

• Locally Advanced Rectal Adenocarcinoma

Interventions

Type	Name	Description
RADIATION	GTV 58.75 Gy/25 fractions(Simultaneous Integrated Boost)	Patients will receive neoadjuvant long course radiotherapy using VMAT or IMAT with daily image guided. Gross tumor volume (GTV): A total dose of 58.75Gy delivered in 25 fractions using a simultaneous integrated boost approach; CTV: 45Gy/25f; Mesorectum lymph node(GTVnd1):58.75Gy/25f ; Lateral lymph node（GTVnd2）：60Gy/25f;
RADIATION	GTV 50 Gy/25 fractions(Simultaneous Integrated Boost)	Patients will receive neoadjuvant radiotherapy with GTV 50 Gy in 25 fractions , delivered with IMRT or VMAT technique. CTV: 45Gy/25f; Mesorectum lymph node(GTVnd1):58.75Gy/25f; Lateral lymph node（GTVnd2）
DRUG	Concurrent Chemotherapy	Concurrent administration of capecitabine (825 mg/m² twice daily, 5 days per week) or XELOX regimen during radiotherapy.
PROCEDURE	Total mesorectal excision (TME) surgery or non-operative management	After treatment, patients will undergo restaging and proceed to total mesorectal excision (TME) or non-operative management ("watch-and-wait") depending on response and clinical assessment.

Timeline

• Start date: 2025-10-01
• Primary completion: 2026-12-01
• Completion: 2028-12-01
• First posted: 2025-09-30
• Last updated: 2025-09-30