Chemoradiation and Consolidation Chemotherapy With or Without Oxaliplatin for Distal Rectal Cancer and Watch and Wait A Multi-center Prospective Randomized Controlled Trial (CCHOWW)

What this Trial Is About

Researchers are evaluating two different chemotherapy regimens following long-course chemoradiation therapy for patients with distal rectal cancer. The study aims to compare fluoropyrimidine alone versus fluoropyrimidine combined with oxaliplatin in consolidation chemotherapy to determine their effect on tumor response and the potential for organ preservation through a Watch and Wait strategy. This multi-center trial focuses on patients with MRI-defined distal rectal tumors classified as mrT2-3N0-1 and assesses tumor response after 12 weeks from radiotherapy completion. Participants receive 54 Gy of radiotherapy with daily capecitabine during treatment, followed by consolidation chemotherapy starting one week after radiotherapy ends. One group receives fluoropyrimidine alone, while the other receives fluoropyrimidine plus oxaliplatin, with dosing schedules of either mFOLFOX6 or CAPOX over approximately 12 weeks. Tumor response is centrally reviewed at 12 and 18 weeks, with decisions about continuing organ preservation or proceeding to surgery made by a central committee blinded to treatment assignment. Throughout the study, participants undergo clinical exams, endoscopic assessments, and high-resolution MRI to monitor tumor changes and response. The primary outcome is the decision to proceed with the Watch and Wait approach based on clinical complete response at 18 weeks post-radiotherapy. Secondary outcomes include surgery-free survival, total mesorectal excision-free survival, distant metastases-free survival, local regrowth-free survival, and colostomy-free survival assessed over three years. The study includes ongoing safety monitoring and follow-up to evaluate long-term outcomes.

Chemoradiation and Consolidation Chemotherapy With or Without Oxaliplatin for Distal Rectal Cancer and Watch and Wait