Radiation and medication treatment for low rectal cancer

Modified Short-Course Radiation Combined With CAPOX and Tislelizumab for MSS Locally Advanced of Middle and Low Rectal Cancer (mRCAT): An Open-label, Single-arm, Prospective Multicenter Clinical Trial

This study is testing a new treatment combining targeted radiation, chemotherapy, and an immune therapy for patients with middle and low rectal cancer to see if it helps shrink tumors before surgery.

Quick facts

• Phase: Phase 2
• Study type: Interventional
• Enrollment: 32 (estimated)
• Ages: 18 Years to 75 Years
• Sex: All
• Sponsor: Sir Run Run Shaw Hospital (Academic / other)
• Drugs / interventions: immunotherapy, radiation, Tislelizumab
• Locations: 1 site (Hanzhou, Zhejiang)
• Trial ID: NCT05972655 on ClinicalTrials.gov

What this trial studies

This clinical trial evaluates a modified short-course radiation therapy that targets only the tumor bed, combined with the chemotherapy regimen CAPOX and the PD-1 inhibitor Tislelizumab for patients with middle and low rectal cancer. It aims to enroll 32 patients and assess the primary endpoint of pathological complete response (pCR), along with secondary outcomes such as organ preservation rates, tumor regression grades, long-term prognosis, and adverse effects. The study is open-label and multicenter, focusing on patients who are willing to undergo neoadjuvant therapy.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18-75 with histologically confirmed low rectal adenocarcinoma and specific clinical staging criteria.

Not a fit: Patients with prior anti-tumor therapy, immunotherapy, or pelvic radiation are unlikely to benefit from this study.

Why it matters

Potential benefit: If successful, this approach could improve treatment outcomes and organ preservation for patients with low rectal cancer.

How similar studies have performed: While this approach is innovative, similar studies have shown promise in targeting tumor beds while sparing lymph nodes.

Eligibility criteria

Inclusion Criteria:

1. Patients who have a strong willingness to preserve the anus and are willing to receive neoadjuvant therapy.
2. Male or Female aged 18-75.
3. Patients diagnosed with low rectal cancer within 10 cm from the lower edge of the tumor to the anal verge by pelvic MRI and anorectoscopy, the clinical stage is cT2N+M0/cT3-4aN0/+M0, the lymph nodes are limited to the mesorectum, the circumferential resection margin is negative.
4. Histologically confirmed rectal adenocarcinoma; Genetic testing suggests MSI-L or MSS, or tumor biopsy immunohistochemistry reveals pMMR, that is, MSH1, MSH2, MSH6, and PMS2 are all positive.
5. Eastern Cooperative Oncology Group (ECOG) 0-1.
6. No previous treatment(including anti-tumor therapy、immunotherapy or pelvic radiation).
7. Adequate hematologic, hepatic, renal, thyroid and cardiac function: white blood cells ≥3500/mm3, neutrophils ≥1800/mm3, platelets ≥100,000/mm3, hemoglobin ≥100 g/L; activated partial thromboplastin time, prothrombin time and international normalized ratio ≤1.5 × ULN; aspartate aminotransferase and alanine aminotransferase ≤3.0 × upper limit of normal (ULN), bilirubin ≤1.25 × ULN, serum albumin ≥28 g/L. creatinine clearance ≥50 mL/mi, creatinine ≤1.5 × ULN;
8. Informed consent form signed.

Exclusion Criteria:

1. Patients with a previous history of malignant tumors besides rectal cancer.
2. Patients with distant metastases before enrollment.
3. Patients with positive internal or external iliac lymph nodes are assessed by MRI or CT.
4. Patients with obstruction, perforation, or bleeding that require emergency surgery.
5. Patients with severe concomitant diseases and estimated survival time ≤ 5 years.
6. Allergic to any component of the therapy.
7. Patients with poorly differentiated adenocarcinoma, signet ring cell carcinoma, or mucinous adenocarcinoma.
8. Patients who received immunosuppressive or systemic hormone therapy for immunosuppressive purposes within 1 month prior to the initiation of therapy.
9. Patients who have received any other experimental drug (including immunotherapy) or participated in another interventional clinical trial within 30 days before screening.
10. Factors leading to study termination, such as alcoholism, drug abuse, other serious illnesses (including psychiatric disorders) requiring combination therapy, and patients with severe laboratory abnormalities.
11. Patients with congenital or acquired immune deficiency (such as HIV infection).
12. Vulnerable groups, including mentally ill, cognitively impaired, critically ill patients, minors, pregnant or lactating women, illiterate, etc.
13. Other conditions that investigators consider not suitable for this study.

Where this trial is running

Hanzhou, Zhejiang

• Sir Run Run Shao hospital — Hanzhou, Zhejiang, China (Recruiting)

Study contacts

• Study coordinator: Zhangfa Song, M.D, PH.D

Conditions Low Rectal Cancer