Translational Research in Identifying Molecular Mechanisms for Rectal Cancer Metastasis

Study Overview
=================
Brief Summary
-----------------
Rectal cancer, comprised of 30% of overall colorectal cancer cohort, is one of the leading cancers of Taiwan. In patients with advanced disease, the standard of care is concurrent chemoradiotherapy (CCRT) before surgery. After CCRT, the abscopal effect, a phenomenon that localized radiation not only destroys local tumor but also inhibits the growth of tumor at the remote site, has been observed. This effect is believed to be associated with tumor immune response. In addition, other immune checkpoint molecules, such as Programmed cell death-1(PD-1), Programmed cell death ligand-1 (PD-L1), and Cytotoxic T-Lymphocyte Associated Protein 4 (CTLA-4), have been reported associated with therapeutic outcome. However, after CCRT, more than 50% of patients were still either having persistent disease or developed distant metastasis. To improve therapeutic outcome of patients with rectal cancer, this project, thus, aims at exploring the evolution of factors that may affect the abscopal effect and immune checkpoint functions in tissues and in blood before and after CCRT.

Detailed Description
-----------------
For most patients, preoperative chemoradiotherapy results in clinically tumor regression, but the degree of response varies among patients. There are approximately 40-60% of LARC patients treated with CCRT achieve some degree of pathologic response. However, there is yet an effective method before the commencement of CCRT that can predict how patients will respond to CCRT and can subsequently render better survival. Identify patents who will benefit most from CCRT is crucial not only in lowering treatment-related morbidity and sustaining local control but also to improve survival rate in LARC.

Official Title
-----------------
Translational Research in Identifying Molecular Mechanisms for Rectal Cancer Metastasis

Conditions
-----------------
Rectal Cancer, Chemoradiation

Intervention / Treatment
-----------------
* Procedure: Preoperative chemoradiotherapy


Participation Criteria
=================
Eligibility Criteria
-----------------
Inclusion Criteria: Rectal cancer patients in China Medical University Hospital (Age limit: 20 yrs and older) Exclusion Criteria: Pregnancy, Disabilities

Ages Eligible for Study
-----------------
Minimum Age: 20 Years

Sexes Eligible for Study
-----------------
All

Accepts Healthy Volunteers
-----------------
No

Study Plan
=================
How is the study designed?
-----------------

Arms and Interventions

| Intervention/Treatment |
| --- |
|Procedure: Preoperative chemoradiotherapy|Preoperative chemoradiotherapy. 2.5 Gray/fraction (Total in 45-54 Gray)|

What is the study measuring?
-----------------
Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Tumor regression rate | complete tumor regression rate(TRG) with tumor regression graded at at surgical resection at 8 weeks after completion of chemoradiotherapy | within 8 weeks after completion of chemoradiotherapy | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Disease free survival |  | 5 year | 
| Overall survival |  | 5 year | 
| Local recurrence |  | 5 year | 
| Distant metastasis |  | 5 year |