Here is the design of a clinical trial:

Official Title: A Phase II Study of Total Neoadjuvant Therapy for Locally Advanced Gastric Cancer

Included conditions:
- Gastric Cancer
- Neoadjuvant Therapy

Study Armgroups:
- {'label': 'Total Neoadjuvant Chemoradiotherapy', 'type': 'EXPERIMENTAL', 'description': 'Total neoadjuvant chemoradiotherapy arm receives intensity-modulated neoadjuvant chemoradiotherapy (45Gy in 25 fractions) concurrently with oral S-1(40-60mg/m2, orally twice daily every weekday) followed by six cycles of SOX neoadjuvant chemotherapy and surgery', 'interventionNames': ['Radiation: SIB-IMRT', 'Drug: S-1', 'Drug: SOX', 'Procedure: Surgery']}

Interventions:
- {'type': 'RADIATION', 'name': 'SIB-IMRT', 'description': '45Gy in 25 fractions using intensity-modulated radiotherapy to the radiation target', 'armGroupLabels': ['Total Neoadjuvant Chemoradiotherapy']}
- {'type': 'DRUG', 'name': 'S-1', 'description': "40-60mg/m2(according to patient's body surface area), orally twice daily every weekday concurrently with radiotherapy treatment", 'armGroupLabels': ['Total Neoadjuvant Chemoradiotherapy']}
- {'type': 'DRUG', 'name': 'SOX', 'description': 'SOX (S-1: 40\\~60mg, orally twice daily on days 1 to 14, oxaliplatin 130mg/m2 intravenously on day 1, 21 days per cycle)', 'armGroupLabels': ['Total Neoadjuvant Chemoradiotherapy']}
- {'type': 'PROCEDURE', 'name': 'Surgery', 'description': 'Surgery, preferred D2 lymphadenectomy', 'armGroupLabels': ['Total Neoadjuvant Chemoradiotherapy']}

Primary Outcomes:
- {'measure': 'PCR rate', 'description': 'Pathological response were classified into three grades.Grade I signifies that there is little shrinkage in the tumor; only mild regression in the tumor cells is observed under telemicroscope. Grade II shows gross reduction in size of the tumor and marked regression in the cancer cells microscopically, yet viable nests of cancer tissue are still visible. Grade III implies complete or almost total resolution of the tumor on exploration, and disappearance of the tumor tissue microscopically; only remnants of degenerated cancer cells can be seen (so-called ghost cancer cells).', 'timeFrame': '6-8 months'}

Please estimate the sample size based on the assumption: 
Significance level (Î±) is 0.05, power is 80%, and an interim analysis will be conducted after 33 patients are enrolled.
Sample size calculation
        The primary objective is to determine the pCR rate in this trial. According to the results of the prospective phase II trial previously conducted at our center [20], the pCR rate of patients who received NCT was 14% (P0). We assume that after NCRT and six cycles of NCCT, the pCR rate will reach 28% in this study. Taking into consideration the loss of patients and the optimal two-stage design of phase II clinical trials, the test level Î± is 0.05 with a power of 80%. The required sample size of the study will be 82 patients. After 33 patients are enrolled, a planning interim analysis will be conducted. If the number of patients who received pCR is less than five, the study will be closed.