Simultaneous Boost in Neoadjuvant Radiotherapy for Rectal Cancer

NCT07200141 | Not Yet Recruiting Phase 2 DMC

• 1 other identifier: I-25PJ2066
• Study Type: interventional
• Target: 156
• Locations: 0 countries
• Sites: N/A

Brief 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. 1.Does GTV simultaneously boost to 58.75 Gy/25f increase complete response (pCR or cCR) compared with 50 Gy/25f?
2. 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.
3. 3.Receive neoadjuvant radiotherapy with one of the two PGTV dose escalated regimens (with concurrent chemotherapy: oral capecitabine or XELOX).
4. 4.Undergo restaging with imaging and clinical assessment before surgery or observation.
5. 5.Proceed to total mesorectal excision (TME), local excision, or "watch-and-wait" strategy depending on treatment response and patient preference.
6. 6.Be followed regularly with clinical exams, imaging, endoscopy, and laboratory tests to assess efficacy, safety, and long-term outcomes.

Conditions

Locally Advanced Rectal Adenocarcinoma

Keywords

locally advanced rectal cancer; Neoadjuvant Chemoradiotherapy; Dose Escalation; Simultaneous Integrated Boost

Outcome Measures

Primary Outcomes (1)

• CR

  primary tumor achieved pathological complete response or clinical complete response.

  1 year

Secondary Outcomes (5)

• 3-year disease free suvival rate

  3 years

• 3-year local control rate

  3 years

• Tumor Regression Grade

  1 year

• Number of participants with treatment-related adverse events as assessed by CTCAE v5.0

  3 years

• Organ Preservation Rate

  1 year

Study Arms (2)

Experimental Arm (GTV 58.75 Gy/25f)

EXPERIMENTAL

Radiotherapy: long course simultaneous integrated boost radiotherapy * 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 Concurrent Chemotherapy: Concurrent administration of capecitabine (825 mg/m² twice daily, 5 days per week) or XELOX regimen during radiotherapy 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.

Radiation: GTV 58.75 Gy/25 fractions(Simultaneous Integrated Boost); Drug: Concurrent Chemotherapy; Procedure: Total mesorectal excision (TME) surgery or non-operative management

Control Arm (PGTV 50 Gy/25f)

ACTIVE COMPARATOR

Radiotherapy: long course simultaneous integrated boost radiotherapy Gross tumor volume (GTV): A total dose of 50Gy 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 Concurrent Chemotherapy: Concurrent administration of capecitabine (825 mg/m² twice daily, 5 days per week) or XELOX regimen during radiotherapy 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.

Radiation: GTV 50 Gy/25 fractions(Simultaneous Integrated Boost); Drug: Concurrent Chemotherapy; Procedure: Total mesorectal excision (TME) surgery or non-operative management

Interventions

GTV 58.75 Gy/25 fractions(Simultaneous Integrated Boost) RADIATION

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;

Experimental Arm (GTV 58.75 Gy/25f)

GTV 50 Gy/25 fractions(Simultaneous Integrated Boost) RADIATION

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）

Control Arm (PGTV 50 Gy/25f)

Concurrent Chemotherapy DRUG

Concurrent administration of capecitabine (825 mg/m² twice daily, 5 days per week) or XELOX regimen during radiotherapy.

Control Arm (PGTV 50 Gy/25f); Experimental Arm (GTV 58.75 Gy/25f)

Total mesorectal excision (TME) surgery or non-operative management PROCEDURE

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.

Control Arm (PGTV 50 Gy/25f); Experimental Arm (GTV 58.75 Gy/25f)

Eligibility Criteria

• Age: 18 Years - 80 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Age ≥18 and \<80 years
• Histologically confirmed rectal adenocarcinoma
• Tumor located within 10 cm from the anal verge
• MRI staging: T3-T4 and/or N+, M0 (AJCC 8th edition)
• ECOG performance status 0-2
• Adequate bone marrow function: WBC ≥3×10⁹/L, ANC ≥1.5×10⁹/L, PLT ≥100×10⁹/L, Hb ≥90 g/L
• Adequate liver function: TBIL ≤1.5 × ULN, ALT/AST ≤2.5 × ULN
• Adequate renal function: Cr ≤1.5 × ULN or CCr ≥60 mL/min
• Signed informed consent

You may not qualify if:

• Prior rectal cancer surgery
• Prior induction chemotherapy, immunotherapy, or pelvic radiotherapy
• History of other malignancies
• History of chronic colitis, ulcerative colitis, or nonspecific proctitis
• Pregnant or breastfeeding women
• Active infection or fever
• Severe uncontrolled comorbidities (e.g., unstable heart disease, renal disease, chronic hepatitis, uncontrolled diabetes, psychiatric disorders)
• Inability to comply with study protocol

Sponsors & Collaborators

• Peking Union Medical College Hospital: lead

MeSH Terms

Interventions

Surgical Procedures, Operative

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: TRIPLE
• Who Masked: PARTICIPANT, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: September 22, 2025
• First Posted: September 30, 2025
• Study Start: October 1, 2025
• Primary Completion (Estimated): December 1, 2026
• Study Completion (Estimated): December 1, 2028
• Last Updated: September 30, 2025

Record last verified: 2025-09