Simultaneous Boost in Neoadjuvant Radiotherapy for Rectal Cancer (SIB-NCRT-pumch)

Chinese Academy of Medical Sciences & Peking Union Medical College

Status and phase: Not yet enrolling; Phase 2

Conditions: Locally Advanced Rectal Adenocarcinoma

Treatments: Drug: Concurrent Chemotherapy; Radiation: GTV 58.75 Gy/25 fractions(Simultaneous Integrated Boost); Radiation: GTV 50 Gy/25 fractions(Simultaneous Integrated Boost); Procedure: Total mesorectal excision (TME) surgery or non-operative management

Study type: Interventional

Funder types: Other

Identifiers

NCT07200141

I-25PJ2066

Details and patient eligibility

About

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.

Enrollment: 156 estimated patients

Sex: All

Ages: 18 to 80 years old

Volunteers: No Healthy Volunteers

Inclusion criteria

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

Exclusion criteria

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

Trial design

Primary purpose: Treatment

Allocation: Randomized

Interventional model: Parallel Assignment

Masking: Triple Blind

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156 participants in 2 patient groups

Experimental Arm (GTV 58.75 Gy/25f)

Experimental group

Description:

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.

Treatment:

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

Drug: Concurrent Chemotherapy

Radiation: GTV 58.75 Gy/25 fractions(Simultaneous Integrated Boost)

Control Arm (PGTV 50 Gy/25f)

Active Comparator group

Description:

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.

Treatment:

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

Radiation: GTV 50 Gy/25 fractions(Simultaneous Integrated Boost)

Drug: Concurrent Chemotherapy