Evaluation of the Efficacy and Safety of Rivaroxaban Versus Enoxaprin (Low-Molecular-Weight Heparin) As Post-surgical Thromboprohylaxis of Colorectal Cancer: A Randomized Clinical Trial

To determine the efficacy and safety of rivaroxaban as thromboprophylaxis after colorectal cancer surgery compared to LMWH

The intervention group will receive oral rivaroxaban for 28 days, while the control group will receive subcutaneous enoxaparin for 28 days. Patients will be allocated in parallel at a 1:1 ratio, with 55 patients randomly assigned to each group.

This study will be conducted on patients with colorectal cancer who undergo surgery in the Colorectal Surgery Department of Imam Khomeini Hospital, Tehran, in 2026. Randomization will be performed using a computer-generated random list, in a double-blind manner.

Inclusion: Age over 18 years; candidate for colorectal cancer surgery; pathological confirmation of colorectal adenocarcinoma; patient consent; hospitalization for 6 to 7 days following surgery; creatinine clearance ≥30 mL/min; ALT/AST <3 times the upper limit of normal Exclusion: Active bleeding; high risk of bleeding with anticoagulant use; concurrent use of anticoagulants (particularly warfarin and apixaban); use of dabigatran or edoxaban; history of heparin-induced thrombocytopenia; icreatinine clearance <30 mL/min; Child-Pugh Class C; pregnancy or lactation; platelet count <50,000/μL; major bleeding within the past 30 days; emergency surgery; metastatic disease with a life expectancy of less than three months; history of thromboembolism within the past 3 months

Patients in this group will receive Rivaroxaban 10 mg orally, once daily, starting 6-10 hours after surgery. The duration of treatment will be 28 days. Rهvaroxaban group= 55 patients

Venous thromboembolism, including DVT or PE, asymptomatic DVT detected by ultrasound, or VTE-related death within 90 days after surgery. Major bleeding, clinically relevant non-major bleeding, treatment adherence

Sequentially numbered, opaque, sealed envelopes will be used. These envelopes will be prepared by an individual with no executive or clinical role in the study, and the codes on them will correspond to the master randomization list. Only after final confirmation of eligibility criteria and obtainment of written informed consent will the envelope corresponding to the patient be opened in numerical sequence. This process completely prevents selection bias at the stage of study enrollment. The study will be conducted in a double-blind manner. Given the difference in the physical nature of the medications (tablet versus prefilled syringe), all medications and injection supplies will be placed in kit-like packaging (Study Kits) with completely identical appearance, weight, and dimensions. Each medication kit will bear only a unique identification code. Patients, nursing staff, treating physicians, and even outcome assessors (Doppler ultrasound specialists) will remain blinded to the contents of the kits until the completion of the data analysis phase. The master code list will be held exclusively by the Principal Investigator in an encrypted file. Unblinding will be performed only in medical emergencies where knowledge of the drug type is essential to save the patient's life, in accordance with the approved protocol.

Patient data, including age, sex, body mass index (BMI), cancer stage, type of surgery, and history of previous venous thromboembolism (VTE), will be recorded without including any patient identifiers in the final report. The study protocol will document the methodology of randomization, the study period, the patient follow-up procedures, and the patient selection criteria. A blank copy of the informed consent form will be included in the study documentation, and the completed informed consent forms of all participants will be securely retained. Upon completion of the study, statistical analyses will be performed on the collected variables, and the results will be presented in the final report

Access to the study data will begin three months after publication of the study results.

Data access will be granted only to researchers affiliated with accredited academic and scientific institutions.

The data may be used for conducting related research, including literature reviews, systematic reviews, and meta-analyses.

via email to: aysa.rezaei80@gmail.com or jamil.nadimi@gmail.com

To obtain access to the data, applicants will be required to provide their full name, academic affiliation and position, and a summary of their research background. They must also submit a description of the purpose of the data request, the proposed research plan, and the anticipated timeline and method for dissemination of the study findings.