Here is the design of a clinical trial:

Official Title: Rationale and Design of a Prospective, Multicenter Phase Ⅱ Clinical Trial of Safety and Efficacy Evaluation of Long Course Neoadjuvant Chemoradiotherapy Plus Tislelizumab Followed by TME for LARC.

Included conditions:
- Colorectal Neoplasms

Study Armgroups:
- {'label': 'long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations', 'type': 'EXPERIMENTAL', 'description': 'long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations in patients with locally advanced rectal cancer', 'interventionNames': ['Combination Product: long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations']}

Interventions:
- {'type': 'COMBINATION_PRODUCT', 'name': 'long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations', 'description': 'long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations in patients with locally advanced rectal cancer', 'armGroupLabels': ['long course radiotherapy + capecitabine + PD-1 monoclonal antibody treatment combinations']}

Primary Outcomes:
- {'measure': 'pathologic complete response（pCR）', 'description': 'All the enrolled patients will receive total mesorectal excision (TME) 7-9 weeks after the end of long course radiotherapy. The rectal specimens will be evaluated by the pathologists who are experienced on the rectal cancer diagnosis according to the 1997 Dworak grading system. The rectal cancer will be classified into 5 grades. Grade 0-3 will be considered as non-pCR while grade 4 represent pCR.', 'timeFrame': '1 year'}

Please estimate the sample size based on the assumption: 
The required sample size was calculated with 80% power, 95% confidence intervals, and a 10% loss of follow-up rate. Statistical analyses will use SPSS software (version 22.0), with 2-tailed analyses, 5–95% confidence intervals, and p-values < 0.05 considered statistically significant.
Sample size and statistical analysis
        This study is designed as a multicenter, single-arm phase II clinical trial. The pCR rate of single preoperative NCRT is assumed to be about 15% according to previous studies [14, 15]. On the other hand, the expectant pCR rate in this trail will be 40%. The required sample size was calculated to be 50 patients with 80% power and 95% confidence intervals. Moreover, 10% loss of follow-up rate is also considered. Such sample size was calculated using PASS software (version 15).
        Statistical analyses will be in progress using the SPSS software (version 22.0). All analyses were 2-tailed. The confidence interval was 5â95%. p-valuesâ<â0.05 were considered as statistically significant. Continuous variables will be presented as meansâÂ±âstandard deviation and analyzed using an unpaired t-test with Welchâs correction. Categorical variables will be presented as number and percentage and analyzed using chi-square test with Fisherâs exact test. The KaplanâMeier method and log-rank test were used to calculate the DFS and OS.