Here is the design of a clinical trial:

Official Title: Comparison of the Pathological Effect Between 2 and 4 Cycles Neoadjuvant CAPOX for Low/Intermediate Risk II/III Rectal Cancer：a Prospective, Non-inferior, Randomized, Controlled Trial

Included conditions:
- Rectal Cancer
- Neoadjuvant Chemotherapy

Study Armgroups:
- {'label': '2 cycles group', 'type': 'EXPERIMENTAL', 'description': 'patients which recruited have 2 cycles Capox regimen (oxaliplatin: 130 mg/m2 iv d 1, capecitabine: 1000 mg/m2 bid d 1-14, repeated at 3 week intervals), then those patients with no sever chemotheraputic AE, have TME operation after reevaluation and randomization.', 'interventionNames': ['Drug: Capox chemotherapy']}
- {'label': '4 cycles group', 'type': 'OTHER', 'description': 'patients which recruited have 2 cycles Capox regimen (oxaliplatin: 130 mg/m2 iv d 1, capecitabine: 1000 mg/m2 bid d 1-14, repeated at 3 week intervals), then those patients with no sever chemotheraputic AE, have two more cycles chemotherapy and TME operation after reevaluation and randomization.', 'interventionNames': ['Drug: Capox chemotherapy']}

Interventions:
- {'type': 'DRUG', 'name': 'Capox chemotherapy', 'description': 'oxaliplatin: 130 mg/m2 iv d 1, capecitabine: 1000 mg/m2 bid d 1-14, repeated at 3 week intervals', 'armGroupLabels': ['2 cycles group', '4 cycles group']}

Primary Outcomes:
- {'measure': 'pathological Tumor Regression Grade evaluation', 'description': 'pTRG', 'timeFrame': '12 weeks'}

Please estimate the sample size based on the assumption: 
Non-inferiority test with α = 0.05, power (1-β) = 0.8, non-inferiority margin (hazard ratio) δ = 0.05, Pearson chi-square test, 10% withdrawal/lost to follow-up rate, 6% dropout rate in the 4 cycles CAPOX group.
Sample size calculation
        According to phase II trial [16], the proportion of patients who had poor pathological remission (pTRG 3) after 4 cycles of CAPOX was 27.9%. The proportion of pTRG3 after 2 cycles of CAPOX is expected to increase by no more than 10%. The non-inferiority test is used with Î±â=â0.05, (1-Î²)â=â0.8, and the non-inferiority margin (hazard ratio) value Î´ is set as 0.05. Pearson chi-square test is used to calculate the sample size required for the experiment, and 249 samples are required for each group calculated by a normal approximation algorithm [25]. Ten percent of patients are estimated to withdraw from the group or lost to follow-up; 277 patients are needed in each group. The planned enrollment time is 2.5Â years, and the total number of patients is about 554 cases. Meanwhile, it is assumed that the dropout rate of patients in the 4 cycles of the CAPOX group is about 6% due to intolerance of chemotherapy. Therefore, it is estimated that 294 patients would be included in the 2 cycles of the CAPOX group and 260 patients in the 4 cycles of the CAPOX group.