Here is the design of a clinical trial:

Official Title: JCOG1801: A Phase III Randomized Controlled Trial Comparing Surgery Plus Adjuvant Chemotherapy With Preoperative Chemoradiotherapy Followed by Surgery Plus Adjuvant Chemotherapy for Locally Recurrent Rectal Cancer (RC-SURVIVE Study)

Included conditions:
- Rectal Cancer Recurrent

Study Armgroups:
- {'label': 'Arm A', 'type': 'EXPERIMENTAL', 'description': 'Preoperative chemoradiotherapy (CRT) followed by Surgery plus Adjuvant chemotherapy\n\nPreoperative CRT: capecitabine (1650 mg/m2/day) and radiotherapy (50.4 Gy/28 Fr)\n\nAdjuvant chemotherapy: CAPOX (capecitabine+oxaliplatin) or mFOLFOX6 (5-fluorouracil+l-leucovorin+oxaliplatin) or capecitabine or 5-fluorouracil (FU) +l-leucovorin (LV)\n\nCAPOX: oxaliplatin (130 mg/m2/day, day 1) and oral capecitabine (2000 mg/m2/day, twice daily, days 1-14)\n\nmFOLFOX6: oxaliplatin 85 mg/m2 with l-LV 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion over 46 hours.\n\nCapecitabine: 2000 mg/m2/day, twice daily, days 1-14\n\n5-FU+l-LV: leucovorin 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion for over 46 hours', 'interventionNames': ['Drug: Chemotherapy', 'Radiation: Preoperative radiotherapy', 'Other: Procedure']}
- {'label': 'Arm B', 'type': 'ACTIVE_COMPARATOR', 'description': 'Surgery plus Adjuvant chemotherapy\n\nAdjuvant chemotherapy: CAPOX or mFOLFOX6 or capecitabine or 5-FU+l-LV\n\nCAPOX: oxaliplatin (130 mg/m2/day, day 1) and oral capecitabine (2000 mg/m2/day, twice daily, days 1-14)\n\nmFOLFOX6: oxaliplatin 85 mg/m2 with l-LV 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion over 46 hours.\n\nCapecitabine: 2000 mg/m2/day, twice daily, days 1-14\n\n5-FU+l-LV: leucovorin 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion for over 46 hours', 'interventionNames': ['Drug: Chemotherapy', 'Other: Procedure']}

Interventions:
- {'type': 'DRUG', 'name': 'Chemotherapy', 'description': 'Adjuvant chemotherapy: CAPOX or mFOLFOX6 or capecitabine or 5-FU+l-LV\n\nCAPOX: oxaliplatin (130 mg/m2/day, day 1) and oral capecitabine (2000 mg/m2/day, twice daily, days 1-14)\n\nmFOLOX6: oxaliplatin 85 mg/m2 with l-LV 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion over 46 hours.\n\nCapecitabine: 2000 mg/m2/day, twice daily, days 1-14\n\n5-FU+l-LV: leucovorin 200 mg/m2 for over 2 hours followed by a fluorouracil 400 mg/m2 bolus and 2400 mg/m2 continuous infusion for over 46 hours', 'armGroupLabels': ['Arm A', 'Arm B'], 'otherNames': ['CAPOX or mFOLFOX6 or capecitabine or 5-FU+l-LV']}
- {'type': 'RADIATION', 'name': 'Preoperative radiotherapy', 'description': 'Preoperative chemoradiotherapy (CRT) followed by Surgery plus Adjuvant chemotherapy\n\nPreoperative CRT: capecitabine (1650 mg/m2/day) and radiotherapy (50.4 Gy/28 Fr)', 'armGroupLabels': ['Arm A'], 'otherNames': ['Capecitabine plus radiotherapy']}
- {'type': 'OTHER', 'name': 'Procedure', 'description': 'Surgery for Locally Recurrent Rectal Cancer (LRRC) will be performed within 42 days from registration for the patients in arm A, and between days 56 and 98 from the completion of the preCRT for the patients in arm B.\n\nAppropriate surgical procedure will be performed to achieve R0 resection, such as low anterior resection, super low anterior resection, intersphincteric resection, Hartmann procedure, rectal amputation, pelvic exenteration, tumor resection, or lateral lymph node dissection', 'armGroupLabels': ['Arm A', 'Arm B'], 'otherNames': ['Surgery']}

Primary Outcomes:
- {'measure': 'Locally recurrent free survival', 'description': 'the period from registration in the trial to either the first event of local relapse or death from any cause and censored at the last date of contact for a living patient', 'timeFrame': '3-years after registration'}

Please estimate the sample size based on the assumption: 
A one-sided alpha of 0.1 is assumed, with an estimated statistical power within the range of 0.80-0.99, anticipated to remain at or above 0.8.
Sample size and power calculation
        The planned sample size of JCOG1801 is 110 participants, with approximately 40 expected to be enrolled in this correlative study. This is because the present investigation is a prospective observational study, with approximately 60 patients already enrolled at its inception, we have established a maximum sample size of 40 patients based on eligibility and the availability of blood samples. At the time of the primary analysis, JCOG1801 anticipates 56 events for LRFS, which equates to approximately 21 events among participants in JCOG1801A1. Based on the results from the GALAXY study,8 an observational study evaluating the association of ctDNA dynamics with clinical outcomes for patients with colorectal cancer in CIRCULATE-Japan, we conjectured that the proportion of ctDNA-positive patients would be 0.2â0.3 and an HR for LRFS comparing ctDNA-positive to ctDNA-negative would be 0.1â0.3. With the assumption of a one-sided alpha of 0.1, the estimated statistical power is within the range of 0.80â0.99, and it is anticipated to remain at or above 0.8.
        The analyses of this study, comparing the ctDNA status and clinical end points such as the proportion of patients with a pathological R0 resection, response rate of pre-CRT, and pCR rate in the pre-CRT arm, will be conducted prior to the primary analysis of JCOG1801. The analysis is intended to use follow-up data collected after March 2025, subject to the approval of the JCOG Data and Safety Monitoring Committee. Conversely, the prognostic end points will be analysed following the completion of the primary analysis of JCOG1801.